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Summary: This tutorial provides guidance on how to integrate email and password authentication for Android applications built with QuickBlox. Gain the skills to implement a secure and widely recognized login system, enhancing your app’s functionality.

Table of Contents

Introduction

Building an engaging Android application often hinges on seamless user experience. A crucial aspect of this experience is secure and convenient user login. Ensuring the security of user data and maintaining user privacy are paramount concerns in app development. Authentication, the process of verifying the identity of users, plays a crucial role in addressing these concerns. Authentication mechanisms not only safeguard sensitive user information but also provide a seamless and secure user experience. Email and password authentication stand out as one of the most widely used and user-friendly approaches

This tutorial will demonstrate how to integrate this authentication method using QuickBlox, a robust platform for real-time communication and data management. It will explain the role of the Authorization Server in the authentication process and provide insights into integrating authentication mechanisms using QuickBlox. By following this guide, you’ll equip your app with a robust authentication system that fosters trust and encourages user retention.

Looking for an alternative authentication method? Check out, A Guide to Phone Number Authentication for Android Apps

Let’s Get Started!

1. Create a New Project in Android Studio

The initial step in crafting your mobile application involves creating an Android project. This foundational process establishes the groundwork for integrating various functionalities, including authentication.

As the official Integrated Development Environment (IDE) for Android, Android Studio provides all the necessary tools for application development.
Here’s a step-by-step guide to creating a new project in Android Studio:

  1. Open Android Studio on your computer.
  2. Click on “New Project” from the welcome screen.
  3. Choose the “Empty Activity” template and click “Next.”
  4. Enter the name of your application, the package name (e.g., com.example.myapp), and the location to save your project.
  5. Select the language (Java or Kotlin) and the minimum SDK version for your app.
  6. Click “Finish” to create your project.

2. Create a project in the QuickBlox admin panel

Next you’ll need to use your QuickBlox Account and initiate a project so that you can access QuickBlox real-time communication functionality for your application.

  1. Sign-up for a QuickBlox account if you don’t already have one. You can sign in with either your Google or GitHub account.
  2. To create an app, click the ‘New app‘ button.
  3. Input the necessary information about your organization into the corresponding fields and click ‘Add‘.
  4. To get your Application ID, Authorization Key, Authorization Secret, and Account Key go to the ‘Overview‘ section of your app in the Dashboard. Don’t forget to ensure that you securely store your app credentials for future utilization within your application.

For a more detailed description of getting started on QuickBlox, read our official documentation.

3. Integration with Authorization Server

The authorization server is a specialized server responsible for verifying user credentials,such as email and password, and granting permissions to access the application. It plays a pivotal role in ensuring security and safeguarding data, overseeing the user authentication process, and providing access only to authorized users.

For detailed information on its functionality and the integration process, check out our Authorization Server implementation documentation.

3.1 Integrating OkHttp with the Authorization Server

You’ll now need to integrate OkHttp with the authorization server. OkHttp is a popular open-source library for Java and Android applications that simplifies making HTTP requests and handling responses. In other words, it helps your app talk to web servers efficiently.

Leveraging libraries such OkHttp provides a handy methodology to interface with the Authorization Server and facilitate data exchange.

The following example demonstrates how the OkHttp library can be integrated with the Authorization Server.

In the RestSource class, there’s a method called getQBTokenFromAuthServer, which is designed to send a request to the Authorization Server to obtain a QuickBlox token based on the provided email and password.

The buildRequestBody method is responsible for creating the request body, which includes the email and password in JSON format. Then, the buildAuthorizationRequest function constructs a Request object for the Authorization Server, specifying the URL and content type.

Additionally, the buildClient method creates an OkHttp client with timeout configurations.

After receiving a response from the Authorization Server, the b function is called to extract the QuickBlox token from the JSON response.

This example demonstrates a simple way to interact with an Authorization Server using OkHttp in Kotlin.

class RestSource {
   fun getQBTokenFromAuthServer(email: String, password: String): String {
       try {
           val requestBody = buildRequestBody(email, password)
           val request = buildAuthServerRequest(requestBody)

           val response = buildClient().newCall(request).execute()

           val isNotSuccessfulResponse = response.isSuccessful
           if (isNotSuccessfulResponse) {
              // Handle error
           }

           val body = response.body?.string()
           if (body?.isBlank() == true) {
               throw Exception("The response without answer content")
           }

           return parseAnswerFrom(body!!)
       } catch (exception: Exception) {
           throw Exception("${exception.message}")
       }
   }

   private fun buildRequestBody(email: String, password: String): RequestBody {
       val requestJsonObject = JSONObject()
       requestJsonObject.put("email", email)
       requestJsonObject.put("password", password)

       val body: RequestBody = requestJsonObject.toString().toRequestBody()

       return body
   }

   private fun buildAuthServerRequest(requestBody: RequestBody): Request {
       val request = Request.Builder().url("https://api-url/session/email")
           .addHeader("Content-Type", "application/json")
       request.post(requestBody)

       return request.build()
   }

   private fun buildClient(): OkHttpClient {
       val clientBuilder: OkHttpClient.Builder =
           OkHttpClient.Builder()
                  .connectTimeout(20,TimeUnit.SECONDS)
                  .writeTimeout(20, TimeUnit.SECONDS)
                  .readTimeout(20, TimeUnit.SECONDS)


       return clientBuilder.build()
   }


   private fun parseAnswerFrom(body: String): String {
       val json = JSONObject(body)
       val session = (json.get("session") as JSONObject)
       val token = session.get("token")

       val result = token.toString()

       return result
   }
}

4. Authorization in QuickBlox

Once the QuickBlox token is obtained from the Authorization Server, the subsequent step involves its utilization for authentication within the QuickBlox Android SDK. To accomplish this task, developers can employ the signInToQuickBloxWithEmailAndPassword method. This method facilitates authentication by accepting the user’s email and password as parameters and delivers a QuickBlox session object upon successful authentication.

private fun signInToQuickBloxWithEmailAndPassword(email: String, password: String): QBSession? {
    try {
        // Obtaining the QuickBlox token from the auth server
        val qbToken = RestSource().getQBTokenFromAuthServer(email, password)
        
        // Authenticating in QuickBlox using the obtained token
        return QBAuth.startSessionWithToken(qbToken).perform()
    } catch (exception: Exception) {
        // Handling possible errors
        return null
    }
}

The signInToQuickBloxWithEmailAndPassword method operates by initiating a request to the Authorization Server, transmitting the user’s email and password to obtain the QuickBlox token. Subsequently, this token is utilized for authentication within the QuickBlox ecosystem. Upon successful authentication, the method furnishes a QuickBlox session object, empowering seamless interaction with the QuickBlox API.

In the event of any encountered errors during the authentication process, the method implements error handling mechanisms to effectively manage and address them. This ensures the reliability and robustness of the authentication workflow, thereby enhancing the overall user experience and application performance.

Conclusion

Implementing authentication for QuickBlox Android apps using email and password offers a secure and user-friendly approach to safeguarding user data and ensuring privacy. By integrating email and password authentication mechanisms, developers can enhance the security of their applications while providing users with a familiar and accessible login experience.

If you build mobile applications for the Android platform then you are no doubt already familiar with Android Studio, a popular tool and the official Integrated Development Environment (IDE) for Android app development.

Equally, you’ve likely heard of Github and Git. Git is a free and open-source, distributed version control system that lets you manage and track changes in files used in programming. GitHub, is one of many cloud-based hosting services that allows you to manage your Git repositories. Github enables collaborative project development, as multiple programmers can work on project code together. Developers can track and control code changes made by others and, if necessary, return to a state of code before any given change was made, making it an extremely helpful tool.

Android Studio has a user interface that makes it incredibly easy to work with Git without any additional software. In this article, we will show how to clone a repository and work with it using Android Studio and basic Git commands.

Make sure you have a Github account and Android Studio installed and then read on to discover the best way to work with these tools.

Glossary

Before we get started, here are some useful terms worth understanding:

Branch – Branches allow you to work on new features, fix bugs, or develop new ideas in an isolated space within your repository. Branches are needed to isolate development work, so that other branches in the repository are not affected. The existence of branches means that developers can work together on a project and not interfere with each other’s work.

Commit – A commit is like a snapshot (copy) of your repository at specific times. Commits include metadata in addition to the contents and message, like the author, timestamp, and more. The commit history allows you to track changes and if a mistake was made, you can easily find and return to the commit where it happened.

Repository – A repository is a central location where data for your project is stored and managed. A repository contains all of your project’s files and tracks and saves a history of all changes made to files in a project.

The local repository exists on the local machine and can be seen only by the local user.

The remote repository is stored in the cloud, and its local copies are located on the computers of developers. When a developer makes changes to the local version, it can be synchronized with the remote one.

Step 1: Cloning a repository

First you need to open Android Studio.

  1. Press the More Actions command (3-dot icon) on the top row.
  2. Select from the drop-down list “Get from Version Control.”
cloning a repository with Android Studio

Then you need to copy the repository URL that you wish to use from Github.

Go to GitHub and select the project you want to clone and copy the repository URL. For example GitHub – QuickBlox Android Samples. QuickBlox code samples for Android provide an efficient way to add chat or video calling functionality to your application, saving you time from having to code from scratch.

cloning a repository in Android Studio
  1. Press the “Code” button.
  2. Press the Copy URL icon button.

Now return to Android Studio to clone the repository.

cloning a repository with Android Studio
  1. Insert the URL of the repository that you want to clone.
  2. Select the directory where the repository will be cloned.
  3. Press the “Clone” button.

Step 2. Create A New Branch

Now you need to create a new branch where you will work on the code. This is a copy of your workspace in which you can fully work and make changes without affecting the code in the branch from which the copy was made. This allows you to isolate the workflow and not interfere with other developers working on this project.

Create a new branch using Android Studio
  1. Press “Git.”
  2. Select from the drop-down list “Branches.”

This window contains a list of all local and remote branches.

Create a new branch using Android Studio

Press “New Branch

create new branch using Android Studio
  1. Enter the name of the new branch.
  2. Press the “Create” button.

After that, Android Studio will automatically switch to the new branch.

Step 3. Switch branches

To switch between branches you need to go to the window with the list of branches.

Create a new branch using Android Studio
  1. Press the “Git” button.
  2. Select from the drop-down list “Branches.”
switch branches using Android Studio
  1. Select a branch from the list and click on it.
  2. Select “Checkout” from the drop-down list.

This allows you to change the workspace to the branch of your choice.

Step 4. The Commit Command

This is the command to write indexed changes to a Git repository. It saves (writes) states of the branch on the Git project timeline. The “Commit” command should be used after changing something in the project. For example, we have added a new file with the name “Example.java”, and after that, we can save changes to the local repository branch with the commit command.

use commit command in Android Studio
  1. Press the Commit command (green tick icon) on the toolbar.
  2. Provide a brief summary of the changes that were added to this commit.
  3. Press the “Commit” button.

Step 5. The Push Command

The “Push” command will send the local repository branch to the remote repository. It should be used after changes have been committed to a local repository branch. The “push” command can send one or more commits.

Storing data in a remote repository allows you to access content from any computer and other developers who are working on the project can download and apply the actual code to their local repository and stay in sync with the team.

use Push command in Android Studio
  1. Press the Push command (green arrow icon) on the toolbar.
  2. Press the “Push” button.

Step 6. The Pull Command

The “Pull” command is used to retrieve and download content from a remote repository branch and update the local repository branch with that content. This command can be used, for example, if another developer has made changes to the branch code and pushed the changes to a remote repository. For you to have the actual code locally, you need to synchronize your local repository branch with the remote repository branch. After the “Pull” command, the local repository branch will be the same as on the remote.

use the Pull command in Android Studio
  1. Press the Update Project command (blue arrow icon) on the toolbar.
  2. Select “Merge incoming changes into the current branch.”
  3. Press the “OK” button.

Step 7. Using the Log

You can see the history of commits by pressing on the Git in the lower left-hand corner. Here you can find when and by whom the commit was made and what changes were made.

using the log in Android Studio

Conclusion

Android Studio has native integration with Git and GitHub to allow most actions via the Android Studio UI. This makes it much easier to track and manage your Git work, which saves development time. We hope that this article will help you learn how to use basic Git commands with Android Studio so that you can clone a repository and work easily with Git. Happy coding!

Flutter Travel App. Ideal template for listing, social media, and e-commerce applications.

Creating a travel app UI using Flutter involves designing screens like the home screen, destination details, booking screens, and more. Below is an example of how you can start building a simple travel app UI in Flutter.

Prerequisites

Ensure you have Flutter installed and set up on your machine. You can follow the official Flutter installation guide to get started.

Step 1: Setting Up the Project

  1. Create a new Flutter project: flutter create travel_app cd travel_app
  2. Open the project in your preferred IDE (e.g., VSCode, Android Studio).

Step 2: Designing the Home Screen

Let’s start with a basic home screen that displays a list of popular destinations.

lib/main.dart:

import 'package:flutter/material.dart';

void main() {
  runApp(TravelApp());
}

class TravelApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Travel App',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: HomeScreen(),
    );
  }
}

class HomeScreen extends StatelessWidget {
  final List<Map<String, String>> destinations = [
    {
      'name': 'Paris',
      'image': 'https://example.com/paris.jpg',
    },
    {
      'name': 'New York',
      'image': 'https://example.com/newyork.jpg',
    },
    {
      'name': 'Tokyo',
      'image': 'https://example.com/tokyo.jpg',
    },
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Travel App'),
      ),
      body: ListView.builder(
        itemCount: destinations.length,
        itemBuilder: (context, index) {
          return DestinationCard(
            name: destinations[index]['name']!,
            image: destinations[index]['image']!,
          );
        },
      ),
    );
  }
}

class DestinationCard extends StatelessWidget {
  final String name;
  final String image;

  DestinationCard({required this.name, required this.image});

  @override
  Widget build(BuildContext context) {
    return Card(
      margin: EdgeInsets.all(10),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Image.network(
            image,
            height: 200,
            fit: BoxFit.cover,
          ),
          Padding(
            padding: EdgeInsets.all(10),
            child: Text(
              name,
              style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
            ),
          ),
        ],
      ),
    );
  }
}

Step 3: Adding Navigation to Detail Screen

Now, let’s add navigation to a detail screen when a destination is tapped.

lib/main.dart (continued):

import 'package:flutter/material.dart';

void main() {
  runApp(TravelApp());
}

class TravelApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Travel App',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: HomeScreen(),
    );
  }
}

class HomeScreen extends StatelessWidget {
  final List<Map<String, String>> destinations = [
    {
      'name': 'Paris',
      'image': 'https://example.com/paris.jpg',
      'description': 'The City of Light.',
    },
    {
      'name': 'New York',
      'image': 'https://example.com/newyork.jpg',
      'description': 'The Big Apple.',
    },
    {
      'name': 'Tokyo',
      'image': 'https://example.com/tokyo.jpg',
      'description': 'The heart of Japan.',
    },
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Travel App'),
      ),
      body: ListView.builder(
        itemCount: destinations.length,
        itemBuilder: (context, index) {
          return GestureDetector(
            onTap: () {
              Navigator.push(
                context,
                MaterialPageRoute(
                  builder: (context) => DetailScreen(
                    name: destinations[index]['name']!,
                    image: destinations[index]['image']!,
                    description: destinations[index]['description']!,
                  ),
                ),
              );
            },
            child: DestinationCard(
              name: destinations[index]['name']!,
              image: destinations[index]['image']!,
            ),
          );
        },
      ),
    );
  }
}

class DestinationCard extends StatelessWidget {
  final String name;
  final String image;

  DestinationCard({required this.name, required this.image});

  @override
  Widget build(BuildContext context) {
    return Card(
      margin: EdgeInsets.all(10),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Image.network(
            image,
            height: 200,
            fit: BoxFit.cover,
          ),
          Padding(
            padding: EdgeInsets.all(10),
            child: Text(
              name,
              style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
            ),
          ),
        ],
      ),
    );
  }
}

class DetailScreen extends StatelessWidget {
  final String name;
  final String image;
  final String description;

  DetailScreen({required this.name, required this.image, required this.description});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(name),
      ),
      body: SingleChildScrollView(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Image.network(
              image,
              height: 300,
              fit: BoxFit.cover,
            ),
            Padding(
              padding: EdgeInsets.all(16),
              child: Text(
                description,
                style: TextStyle(fontSize: 18),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

Step 4: Adding Some Styling

To make the app more visually appealing, you can enhance the styling of the components.

lib/main.dart (continued with styling):

“`dart
import ‘package:flutter/material.dart’;

void main() {
runApp(TravelApp());
}

class TravelApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Travel App',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: HomeScreen(),
);
}
}

class HomeScreen extends StatelessWidget {
final List> destinations = [
{
'name': 'Paris',
'image': 'https://example.com/paris.jpg',
'description': 'The City of Light.',
},
{
'name': 'New York',
'image': 'https://example.com/newyork.jpg',
'description': 'The Big Apple.',
},
{
'name': 'Tokyo',
'image': 'https://example.com/tokyo.jpg',
'description': 'The heart of Japan.',
},
];

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Travel App'),
),
body: ListView.builder(
itemCount: destinations.length,
itemBuilder: (context, index) {
return GestureDetector(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => DetailScreen(
name: destinations[index]['name']!,
image: destinations[index]['image']!,
description: destinations[index]['description']!,
),
),
);
},
child: DestinationCard(
name: destinations[index]['name']!,
image: destinations[index]['image']!,
),
);
},
),
);
}
}

class DestinationCard extends StatelessWidget {
final String name;
final String image;

DestinationCard({required this.name, required this.image});

@override
Widget build(BuildContext context) {
return Card(
margin: EdgeInsets.all(10),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(15),
),
elevation: 5,
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
ClipRRect(
borderRadius: BorderRadius.vertical(top: Radius.circular(15)),
child: Image.network(
image,
height: 200,
fit: BoxFit.cover,
),
),
Padding(
padding: EdgeInsets.all(10),
child: Text(
name,
style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
),
),
],
),
);
}
}

class DetailScreen extends StatelessWidget {
final String name;
final String image;
final String description;

DetailScreen({required this.name, required this.image, required this.description});

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(name),
),
body: SingleChildScrollView(
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Image.network(
image,
height: 300,
fit: BoxFit.cover,
),
Padding(
padding: EdgeInsets.all(16),
child: Text(
description,
style: TextStyle(font

Explanation

  1. Main Function and App Entry Point: The main function runs the TravelApp widget, which is the root of the app.
  2. MaterialApp: Sets up the app with a title, theme, and home screen.
  3. HomeScreen: A stateless widget that displays the home screen with a list of destinations in a grid view.
  4. Destination Model: A simple class representing a travel destination with a name, image URL, and description.
  5. DestinationCard: A stateless widget to display each destination in a card with an image, name, and description.
  6. Sample Data: A list of sample destinations with dummy data.

You can expand this example by adding more screens (e.g., details screen, profile screen), navigation, and other features. This code provides a starting point for a travel app with a modern and clean UI using Flutter.

This article is an implementation of an intro showcase to highlights different features of the app using Jetpack Compose. The implementation is inspired by the TapTargetView which is useful for legacy views.

The implementation is also available as a standalone library Intro-showcase-view on github which you can directly add as a gradle dependency in your project.

I have divided the implementation into byte size steps. Feel free to skip the steps that you understand or jump directly to the step you are interested in. The final implementation will look like above GIF.

Alright, let’s start coding!!

Step 1: Add a feature and draw circles on Canvas

First, let’s add an email fab button aligned to the bottom of the screen.

@Composable
fun ShowcaseExample() {
val context = LocalContext.current
Box {
FloatingActionButton(
onClick = {
Toast.makeText(
context,
"Fab Clicked",
Toast.LENGTH_SHORT
).show()
},
modifier = Modifier
.align(Alignment.BottomEnd)
.padding(bottom = 16.dp, end = 16.dp),
backgroundColor = ThemeColor,
contentColor = Color.White,
elevation = FloatingActionButtonDefaults.elevation(6.dp)
) {
Icon(
Icons.Filled.Email,
contentDescription = "Email"
)
}

IntroShowCase()
}
}

Then, we’ll create two circles. We’ll use Canvas API to draw our circle.

@Composable
fun IntroShowCase() {
Canvas(
modifier = Modifier
.fillMaxSize()
) {
drawCircle(
color = Color.Black
)
drawCircle(
color = Color.White,
radius = 150f
)
}
}

Pretty Simple…

But, that’s not what we want.

Step 2: Find LayoutCoordinates of a fab button and recenter circle.

We have to set a circle offset to highlight our Fab button. And for that, we need a position of our fab button. We’ll use OnGloballyPositionedModifier property of Modifier we’ll have view’s LayoutCoordinates in a callback.

A modifier whose onGlobalyPositioned is called with the final LayoutCoordinates of the Layout when the global position of the content may have changed. Note that it will be called after a composition when the coordinates are finalized.

Let’s modify the modifier of fab button to get its coordinates.

@Composable
fun showcaseExample() {

var target by remember {
mutableStateOf<LayoutCoordinates?>(null)
}
val
context = LocalContext.current

Box {
FloatingActionButton(
....
modifier = Modifier
.align(Alignment.BottomEnd)
.onGloballyPositioned { coordinates ->
target = coordinates
}
....

) {
....

}

target?.let {
IntroShowCase(it)
}
}
}

Now let’s use this coordinate to recenter our circle. Here’s how,

@Composable
fun IntroShowCase(targetCords: LayoutCoordinates) {
val targetRect = targetCords.boundsInRoot()

Canvas(
modifier = Modifier
.fillMaxSize()
) {
drawCircle(
color = Color.Black,
center = targetRect.center
)
drawCircle(
color = Color.White,
radius = 150f,
center = targetRect.center
)
}
}

We have used our target view Rect’s center offset to center our circle.

Oops!!, Where’s our fab button?. Our fab button is overlapped by circles.

Step 3: Blend the overlapped circle to set transparency

We have to set transparency where both circles are overlapped. We’ll use BlendMode to fix this and also let’s fix the radius of the inner circle based on our target view dimension.

BlendMode.Clear : Drop both the source and destination images, leaving nothing.

@Composable
fun IntroShowCase(targetCords: LayoutCoordinates) {
val targetRect = targetCords.boundsInRoot()
val targetRadius = targetRect.maxDimension / 2f + 40f
// 40f extra traget spacing

Canvas(
modifier = Modifier
.fillMaxSize().graphicsLayer (alpha = 0.99f)
) {
drawCircle(
color = Color.Black,
center = targetRect.center
)
drawCircle(
color = Color.White,
radius = targetRadius,
center = targetRect.center,
blendMode = BlendMode.Clear
)
}
}

Perfect!! Isn’t it?

Step: 4 Add circle reveals animation to highlight target

Now, Let’s add an animation around our target view

val animationSpec = infiniteRepeatable<Float>(
animation = tween(2000, easing = FastOutLinearInEasing),
repeatMode = RepeatMode.Restart,
)
val animatables = listOf(
remember { Animatable(0f) },
remember { Animatable(0f) }
)

animatables.forEachIndexed { index, animatable ->
LaunchedEffect(animatable) {
delay(index * 1000L)
animatable.animateTo(
targetValue = 1f, animationSpec = animationSpec
)
}
}

val
dys = animatables.map { it.value }Canvas(
...
) {
...


dys.forEach { dy ->
drawCircle(
color = Color.White,
radius = targetRect.maxDimension * dy * 2f,
center = targetRect.center,
alpha = 1 - dy
)
}
...
}

Let’s try to understand this, We have used infiniteRepeatable , as we want our animation to run infinitely.

animatables is the array of Animatable, We have set up the initial delay for the second wave, We can not use delayMillis as that is considered for repeat animation as well. We just want to delay the initial animation, and then continue the loop without any delay.

we created an animation that will animate between 0 to 1 infinitely. Based on that, we have set up a radius and animated alpha between 1 to 0, which will make waves disappear at the end of an animation.

Let’s see what it look likes,

Step 5: Add texts to describe the feature

Let’s create a data class that holds the value of our targets coordinates, title, subtitle, colors, etc.

data class ShowcaseProperty(
val index: Int,
val coordinates: LayoutCoordinates,
val title: String, val subTitle: String,
val titleColor: Color = Color.White,
val subTitleColor: Color = Color.White,
)

Okay, for now, let’s ignore index field, we’ll use it later to manage the order of when we have multiple features. Let’s refactor our composable a bit.

@Composable
fun IntroShowCase(target: ShowcaseProperty) {
val targetRect = target.coordinates.boundsInRoot()
val targetRadius = targetRect.maxDimension / 2f + 40f

val animationSpec = infiniteRepeatable<Float>(
animation = tween(2000, easing = FastOutLinearInEasing),
repeatMode = RepeatMode.Restart,
)
val animatables = listOf(
remember { Animatable(0f) },
remember { Animatable(0f) }
)

animatables.forEachIndexed { index, animatable ->
LaunchedEffect(animatable) {
delay(index * 1000L)
animatable.animateTo(
targetValue = 1f, animationSpec = animationSpec
)
}
}

val
dys = animatables.map { it.value }

Box {

Canvas(
modifier = Modifier
.fillMaxSize()
.graphicsLayer(alpha = 0.99f)
) {
drawCircle(
color = Color.Black,
center = targetRect.center
)

dys.forEach { dy ->
drawCircle(
color = Color.White,
radius = targetRect.maxDimension * dy * 2f,
center = targetRect.center,
alpha = 1 - dy
)
}

drawCircle(
color = Color.White,
radius = targetRadius,
center = targetRect.center,
blendMode = BlendMode.Clear
)
}

ShowCaseText(
currentTarget = target
)
}
}@Composable
private fun ShowCaseText(
currentTarget: ShowcaseProperty,
) {

Column(modifier = Modifier
.padding(16.dp)
)
{
Text(
text = currentTarget.title,
fontSize = 24.sp,
color = currentTarget.subTitleColor,
fontWeight = FontWeight.Bold
)
Text(text = currentTarget.subTitle, fontSize = 16.sp, color = currentTarget.subTitleColor)
}
}

We just have added two Text for title and subtitle, let’s see the output.

But that’s not even near to our circles.

Step 6: Set offset of Texts

Here we need to check the top and bottom space to set up our text in free space. So we’re going to do it in onGloballyPositioned we’ll calculate the Y offset of our Text, based on total text height and the center of our target. Here’s how.

@Composable
fun IntroShowCaseEx(target: ShowcaseProperty){
....
val targetRect = target.coordinates.boundsInRoot()
val targetRadius = targetRect.maxDimension / 2f + 40f
Box {
ShowCaseText(target, targetRect, targetRadius)
}
....
}
@Composable
private fun ShowCaseText(
currentTarget: ShowcaseProperty,
targetRect: Rect,
targetRadius: Float
) {

var txtOffsetY by remember {
mutableStateOf(0f)
}

Column(modifier = Modifier
.offset(y = with(LocalDensity.current) {
txtOffsetY.toDp()
})
.onGloballyPositioned {
val
textHeight = it.size.height

val
possibleTop =
targetRect.center.y - targetRadius - textHeight

txtOffsetY = if (possibleTop > 0) {
possibleTop
} else {
targetRect.center.y + targetRadius
}
}
.padding(16.dp)
)
{
Text(
text = currentTarget.title,
fontSize = 24.sp,
color = currentTarget.subTitleColor,
fontWeight = FontWeight.Bold
)
Text(text = currentTarget.subTitle, fontSize = 16.sp, color = currentTarget.subTitleColor)
}

}

And here’s the result.

But, the Text is not in the radius of our circle.

Step 7: Calculate outer circle radius

We have to estimate the rectangle which includes our text, and our target view including its spacing.

fun getOuterRadius(textRect: Rect, targetRect: Rect): Float {

val topLeftX = min(textRect.topLeft.x, targetRect.topLeft.x)
val topLeftY = min(textRect.topLeft.y, targetRect.topLeft.y)
val bottomRightX = max(textRect.bottomRight.x, targetRect.bottomRight.x)
val bottomRightY = max(textRect.bottomRight.y, targetRect.bottomRight.y)

val expandedBounds = Rect(topLeftX, topLeftY, bottomRightX, bottomRightY)

val d = sqrt(
expandedBounds.height.toDouble().pow(2.0)
+ expandedBounds.width.toDouble().pow(2.0)
).toFloat()

return (d / 2f)
}

Okay, we just have found the rectangle of our content, and from that, we got the radius.

var textCoordinate: LayoutCoordinates? by remember {
mutableStateOf(null)
}
var
outerRadius by remember {
mutableStateOf(0f)
}
textCoordinate?.let { textCoords ->
val
textRect = textCoords.boundsInRoot()
outerRadius = getOuterRadius(textRect, targetRect) + targetRadius
}Box {
Canvas(
modifier = Modifier
.fillMaxSize()
.graphicsLayer(alpha = 0.99f)
) {
drawCircle(
color = Color.Black,
center = targetRect.center,
radius = outerRadius,
alpha = 0.9f
)

dys.forEach { dy ->
drawCircle(
color = Color.White,
radius = targetRect.maxDimension * dy * 2f,
center = targetRect.center,
alpha = 1 - dy
)
}

drawCircle(
color = Color.White,
radius = targetRadius,
center = targetRect.center,
blendMode = BlendMode.Clear
)
}

ShowCaseText(
currentTarget = target,
targetRect = targetRect,
targetRadius = targetRadius
) {
textCoordinate = it
}
}

Let’s see the result.

Nope, That’s not enough to cover the whole content.

Step 8: change the offset of our outer circle

Now, let’s find the center offset of the outer circle which includes our target and texts.

var outerOffset by remember {
mutableStateOf(Offset(0f, 0f))
}textCoordinate?.let { textCoords ->
val
textRect = textCoords.boundsInRoot()
val textHeight = textCoords.size.height

outerOffset = getOuterCircleCenter(
targetRect, textRect, targetRadius, textHeight
)

outerRadius = getOuterRadius(textRect, targetRect) + targetRadius
}Box {
Canvas(
modifier = Modifier
.fillMaxSize()
.graphicsLayer(alpha = 0.99f)
) {
drawCircle(
color = Color.Black,
center = outerOffset,
radius = outerRadius,
alpha = 0.9f
)

dys.forEach { dy ->
drawCircle(
color = Color.White,
radius = targetRect.maxDimension * dy * 2f,
center = targetRect.center,
alpha = 1 - dy
)
}

drawCircle(
color = Color.White,
radius = targetRadius,
center = targetRect.center,
blendMode = BlendMode.Clear
)
}

ShowCaseText(
currentTarget = target,
targetRect = targetRect,
targetRadius = targetRadius
) {
textCoordinate = it
}
}
fun getOuterCircleCenter(
targetBound: Rect,
textBound: Rect,
targetRadius: Float,
textHeight: Int,
): Offset {
var outerCenterX: Float
var outerCenterY: Float

val onTop =
targetBound.center.y - targetRadius - textHeight > 0

val left = min(
textBound.left,
targetBound.left - targetRadius
)
val right = max(
textBound.right,
targetBound.right + targetRadius
)

val centerY =
if (onTop) targetBound.center.y - targetRadius - textHeight
else targetBound.center.y + targetRadius + textHeight

outerCenterY = centerY
outerCenterX = (left + right) / 2

return Offset(outerCenterX, outerCenterY)
}

Looks cool!!

But what if our target is in a toolbar or bottom bar? Let’s see by changing the alignment of our fab button to TopEnd .

Not so perfect!!.

Step 9: Fix the outer circle center point for the Top and Bottom bar.

We have to recheck our center point of an outer circle when our target is in the toolbar or at the bottom of the screen.

Here’s how

val topArea = 88.dp
val screenHeight = LocalConfiguration.current.screenHeightDp
val
yOffset = with(LocalDensity.current) {
target.coordinates.positionInRoot().y.toDp()
}var outerOffset by remember {
mutableStateOf(Offset(0f, 0f))
}textCoordinate?.let { textCoords ->
val
textRect = textCoords.boundsInRoot()
val textHeight = textCoords.size.height
val
isInGutter = topArea > yOffset || yOffset > screenHeight.dp.minus(topArea)

outerOffset = getOuterCircleCenter(
targetRect, textRect, targetRadius, textHeight, isInGutter
)

outerRadius = getOuterRadius(textRect, targetRect) + targetRadius
}....fun getOuterCircleCenter(
targetBound: Rect,
textBound: Rect,
targetRadius: Float,
textHeight: Int,
isInGutter: Boolean,
): Offset {
var outerCenterX: Float
var outerCenterY: Float

val onTop =
targetBound.center.y - targetRadius - textHeight > 0

val left = min(
textBound.left,
targetBound.left - targetRadius
)
val right = max(
textBound.right,
targetBound.right + targetRadius
)

val centerY =
if (onTop) targetBound.center.y - targetRadius - textHeight
else targetBound.center.y + targetRadius + textHeight

outerCenterY = centerY
outerCenterX = (left + right) / 2

if (isInGutter) {
outerCenterY = targetBound.center.y
}

return Offset(outerCenterX, outerCenterY)
}

If our target is in Gutter we just set targetBound.center.y to outerCenterY and our outerCenterX would be the same as the center X of our content rectangle in both cases.

Let’s check the output now.

Perfect!!

And last but not least…

Step 10: Add circle reveals animation to our outer circle.

val outerAnimatable = remember { Animatable(0.6f) }

LaunchedEffect(target) {
outerAnimatable.snapTo(0.6f)

outerAnimatable.animateTo(
targetValue = 1f,
animationSpec = tween(
durationMillis = 500,
easing = FastOutSlowInEasing,
),
)
}

We have created Animatable with initial value 0.6 as we don’t want our circle to scale from 0.0. If you notice, we have used target here as a key of LaunchedEffect , this will only trigger the inner block when a key changes. Whenever key changes we have reset the current value to the initial value 0.6f using snapTo. Let’s use Animatable value with our outer circle radius.

Box {
Canvas(
modifier = Modifier
.fillMaxSize()
.graphicsLayer(alpha = 0.99f)
) {
drawCircle(
color = Color.Black,
center = outerOffset,
radius = outerRadius * outerAnimatable.value,
alpha = 0.9f
)
}
}

Okay, here’s the result

That’s it!!

Now let’s integrate it with multiple feature showcases. We’re not going to cover all the basic details.onGloballyPositioned may call multiple times so we’ll use an mutableStateMapOf of ShowcaseProperty to avoid duplications.

@Composable
fun ShowcaseSample() {
val targets = remember {
mutableStateMapOf<String, ShowcaseProperty>()
}

Box {
FloatingActionButton(
onClick = {},
modifier = Modifier
.padding(16.dp)
.align(Alignment.BottomEnd)
.onGloballyPositioned { coordinates ->
targets["email"] = ShowcaseProperty(
1, coordinates,
"Check emails", "Click here to check/send emails"
)
},
backgroundColor = ThemeColor,
contentColor = Color.White,
elevation = FloatingActionButtonDefaults.elevation(6.dp)
) {
Icon(
Icons.Filled.Email,
contentDescription = "Email"
)
}
Button(
onClick = {},
modifier = Modifier
.align(Alignment.BottomStart)
.padding(start = 16.dp, bottom = 16.dp)
.onGloballyPositioned { coordinates ->
targets["follow"] = ShowcaseProperty(
2, coordinates,
"Follow me", "Click here to follow"
)
}
) {
Text(text = "Follow")
}


IntroShowCase(targets)
}
}

And Here’s our Intro showcase view

@Composable
fun IntroShowCase(
targets: SnapshotStateMap<String, ShowcaseProperty>,
backgroundColor: Color = Color.Black,
onShowcaseCompleted: () -> Unit
) {
val uniqueTargets = targets.values.sortedBy { it.index }
var
currentTargetIndex by remember { mutableStateOf(0) }

val
currentTarget =
if (uniqueTargets.isNotEmpty() && currentTargetIndex < uniqueTargets.size) uniqueTargets[currentTargetIndex] else null


currentTarget?.let {
TargetContent(it, backgroundColor) {
if
(++currentTargetIndex >= uniqueTargets.size) {
onShowcaseCompleted()
}
}
}
}

Pretty simple!!

Similarly, you can add rest of the views as aShowcaseProperty to make it look like the video shown at the beginning of the article. Full source code is available here.

As I mentioned earlier, the implementation is also available as a library, which you can integrate easily. Feel free to use it in your app and if you want to customize it you’re free to fork.

I’m trying to get the URL of a file that is on my drive, knowing its name and the name of the parent folder. But the result is always null.

I’m using a service account with owner permission, I already put the correct credentials inside the project and shared the folder and file with the service account email, and still, the problem continues. When debugging the code it is possible to see that the size of List<File> folders = result.getFiles();  is 0.

Here is the complete code:

import android.content.Context;

import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.drive.Drive;
import com.google.api.services.drive.DriveScopes;
import com.google.api.services.drive.model.File;
import com.google.api.services.drive.model.FileList;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;

import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;
import java.util.Collections;
import java.util.List;

public class DriveAccessRunnable implements Runnable {

   private static final String APPLICATION_NAME = "School Grade";

   private static final JsonFactory JSON_FACTORY = GsonFactory.getDefaultInstance();

   private static Drive driveService;
   private final Context context;
   private final String parentFolderTitle;
   private final String fileName;
   private final DriveAccessCallback callback;

   public DriveAccessRunnable(Context context, String parentFolderTitle, String fileName, DriveAccessCallback callback) {
      this.context = context;
      this.parentFolderTitle = parentFolderTitle;
      this.fileName = fileName;
      this.callback = callback;
   }

   @Override
   public void run() {
      try {
         // Google Drive access code
         HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
         driveService = new Drive.Builder(httpTransport, JSON_FACTORY, getHttpRequestInitializer())
                 .setApplicationName(APPLICATION_NAME)
                 .build();

         // Get the URL of the file or null if not found
         String fileUrl = getFileUrl(parentFolderTitle, fileName);

        
         // Call the callback with the result
         callback.onFileUrlReceived(fileUrl);
      } catch (IOException | GeneralSecurityException e) {
         e.printStackTrace();
         // Call the callback with an error result
         callback.onError(e.getMessage());
      }

   }

   private HttpRequestInitializer getHttpRequestInitializer() throws IOException {
      InputStream credentialsStream = context.getResources().openRawResource(R.raw.credentials);

      GoogleCredentials credentials = GoogleCredentials.fromStream(credentialsStream)
              .createScoped(Collections.singletonList(DriveScopes.DRIVE_FILE));

      return new HttpCredentialsAdapter(credentials);
   }

   private String getFileUrl(String parentFolderTitle, String fileName) throws IOException {
     
       // Search parent folder by title
      FileList result = driveService.files().list()
              .setQ("mimeType='application/vnd.google-apps.folder' and trashed=false and name='" + parentFolderTitle + "'")
              .setSpaces("drive")
              .setFields("files(id)")
              .execute();

      List<File> folders = result.getFiles();

      if (!folders.isEmpty()) {
         String parentFolderId = folders.get(0).getId();

         
         // Browse files inside the parent folder
         result = driveService.files().list()
                 .setQ("'" + parentFolderId + "' in parents and trashed=false")
                 .setFields("files(name, webViewLink)")
                 .execute();

         List<File> files = result.getFiles();
         for (File file : files) {
            if (file.getName().equals(fileName)) {
               return file.getWebViewLink();
            }
         }
      }

      return null;
   }


   public interface DriveAccessCallback {
      void onFileUrlReceived(String fileUrl);
      void onError(String errorMessage);
   }
}

So I am trying to implement app links from web search to open the app and I want it to use regex to match the below URL example…

/(url-1|url-2)/

Where it can be either of those strings, but it doesn’t seem to work. Is this possible in the pattern matcher?

Anywhere exists a tool to test this, can’t seem to find any other than generic regex testers which are different to the android format here.

I’ll provide you with a sample code and explanation for creating a profile screen with a RecyclerView using Android DataBinding. Here’s a step-by-step guide:

Step 1: Set up your project
Create a new Android project in Android Studio. Make sure you have the necessary dependencies in your build.gradle file:

android {
    // ...
    dataBinding {
        enabled = true
    }
}

Step 2: Create the layout files
Create the following layout files in your project:

activity_profile.xml:

<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="viewModel"
            type="com.example.yourapp.ProfileViewModel" />
    </data>

    <!-- Your profile screen layout here -->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:items="@{viewModel.blogItems}"
            app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
            app:itemLayout="@layout/item_blog" />
    </LinearLayout>
</layout>

item_blog.xml:

<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="blog"
            type="com.example.yourapp.BlogItem" />
    </data>

    <!-- Your blog item layout here -->
</layout>

Step 3: Create the ViewModel and BlogItem classes
Create the following classes in your project:

ProfileViewModel.kt:

class ProfileViewModel : ViewModel() {
    val blogItems: LiveData<List<BlogItem>> = MutableLiveData(
        listOf(
            BlogItem("Title 1", "Content 1"),
            BlogItem("Title 2", "Content 2"),
            BlogItem("Title 3", "Content 3")
        )
    )
}

class BlogItem(val title: String, val content: String)

Step 4: Create the Adapter and ViewHolder
Create the following classes in your project:

BlogAdapter.kt:

class BlogAdapter(private val blogItems: List<BlogItem>) :
    RecyclerView.Adapter<BlogAdapter.ViewHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val inflater = LayoutInflater.from(parent.context)
        val binding: ItemBlogBinding = DataBindingUtil.inflate(
            inflater, R.layout.item_blog, parent, false
        )
        return ViewHolder(binding)
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        holder.bind(blogItems[position])
    }

    override fun getItemCount(): Int = blogItems.size

    class ViewHolder(private val binding: ItemBlogBinding) :
        RecyclerView.ViewHolder(binding.root) {

        fun bind(blogItem: BlogItem) {
            binding.blog = blogItem
            binding.executePendingBindings()
        }
    }
}

Step 5: Connect everything in your Activity or Fragment
Update your ProfileActivity or ProfileFragment to include the following code:

ProfileActivity.kt:

class ProfileActivity : AppCompatActivity() {

    private lateinit var binding: ActivityProfileBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = DataBindingUtil.setContentView(this, R.layout.activity_profile)

        val viewModel = ViewModelProvider(this).get(ProfileViewModel::class.java)
        binding.viewModel = viewModel

        val adapter = BlogAdapter(viewModel.blogItems.value ?: emptyList())
        binding.recyclerView.adapter = adapter
    }
}

That’s it! You have now created a profile screen with a RecyclerView using Android DataBinding. Make sure to replace com.example.yourapp it with the appropriate package name in the code.

Remember to customize the layout files and the BlogItem class according to your requirements. You can also update the blog items dynamically by modifying the blogItems LiveData in the ViewModel.

Hope this helps you get started with your profile screen implementation!

Here’s an example of an Android application that allows users to choose an image from the camera or gallery and perform cropping functionality using the “Android Image Cropper” library.

Step 1: Set up the project

Start by creating a new Android project in Android Studio. Make sure you have the necessary dependencies and permissions in your project’s build.gradle file:

dependencies {
    implementation 'com.theartofdev.edmodo:android-image-cropper:2.8.+'
}

Also, make sure you have the necessary permissions in your AndroidManifest.xml file:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />

Step 2: Create the layout

Create a layout file called activity_main.xml with the following code:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="16dp"
    android:paddingTop="16dp"
    android:paddingRight="16dp"
    android:paddingBottom="16dp"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:adjustViewBounds="true"
        android:scaleType="centerInside"
        android:src="@drawable/placeholder" />

    <Button
        android:id="@+id/btnChooseImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/imageView"
        android:text="Choose Image" />

    <Button
        android:id="@+id/btnCropImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/btnChooseImage"
        android:text="Crop Image"
        android:enabled="false" />

</RelativeLayout>

Step 3: Implement the functionality in the MainActivity

Open MainActivity.java and add the following code:

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import com.theartofdev.edmodo.cropper.CropImage;
import com.theartofdev.edmodo.cropper.CropImageView;

import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_CAMERA_PERMISSION = 200;
    private static final int REQUEST_IMAGE_CAPTURE = 100;
    private static final int REQUEST_IMAGE_GALLERY = 101;

    private ImageView imageView;
    private Button btnChooseImage;
    private Button btnCropImage;

    private Uri imageUri;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        imageView = findViewById(R.id.imageView);
        btnChooseImage = findViewById(R.id.btnChooseImage);
        btnCropImage = findViewById(R.id.btnCropImage);

        btnChooseImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                chooseImage();
            }
        });

        btnCropImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                cropImage(imageUri);
            }
        });
    }

    private void chooseImage() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
        } else {
            openImageChooser();
        }
    }

    private void openImageChooser() {
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.setType("image/*");
        startActivityForResult(intent, REQUEST_IMAGE_GALLERY);
    }

    private void cropImage(Uri imageUri) {
        CropImage.activity(imageUri)
                .setGuidelines(CropImageView.Guidelines.ON)
                .setAspectRatio(1, 1)
                .start(this);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
            cropImage(imageUri);
        } else if (requestCode == REQUEST_IMAGE_GALLERY && resultCode == RESULT_OK && data != null) {
            try {
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), data.getData());
                imageView.setImageBitmap(bitmap);
                imageUri = data.getData();
                btnCropImage.setEnabled(true);
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else if (requestCode == CropImage.CROP_IMAGE_ACTIVITY_REQUEST_CODE) {
            CropImage.ActivityResult result = CropImage.getActivityResult(data);
            if (resultCode == RESULT_OK) {
                Uri resultUri = result.getUri();
                try {
                    Bitmap croppedBitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), resultUri);
                    imageView.setImageBitmap(croppedBitmap);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } else if (resultCode == CropImage.CROP_IMAGE_ACTIVITY_RESULT_ERROR_CODE) {
                Exception error = result.getError();
                error.printStackTrace();
            }
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_CAMERA_PERMISSION && grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            openImageChooser();
        }
    }
}

That’s it! Now you have an Android application that allows users to choose an image from the camera or gallery and perform cropping functionality. Remember to replace the placeholder image with an actual placeholder image of your choice.

Note: Don’t forget to add the necessary runtime permissions check in your code to handle permissions for accessing the camera and gallery.

Step 1: Sign up for a Paytm merchant account
To integrate the PayTM payment gateway, you need to sign up for a PayTM merchant account. Visit the PayTM Developer Portal (https://developer.paytm.com/) and follow the registration process to create your merchant account.

Step 2: Set up PayTM SDK in your project

  1. Open your Android project in Android Studio.
  2. Add the following dependency to your app-level build. gradle file:
implementation 'com.paytm:pgplussdk:1.4.3'
  1. Sync your project to download the PayTM SDK.

Step 3: Obtain merchant credentials
After signing up for a merchant account, you will receive the necessary credentials from PayTM. These include the merchant ID and merchant key, which you’ll need for integration.

Step 4: Create a PayTM activity
Create a new activity in your Android project to handle the PayTM payment process. For example, create a PaytmActivity.java file.

Step 5: Implement the PayTM payment process
In the PaytmActivity.java file, implement the following steps:

  1. Initialize the PayTM service in the onCreate() method:
PaytmPGService service = PaytmPGService.getStagingService(); // or PaytmPGService.getProductionService() for production environment
  1. Set up the payment parameters and listener:
HashMap<String, String> paramMap = new HashMap<>();
paramMap.put("MID", "YOUR_MERCHANT_ID");
paramMap.put("ORDER_ID", "UNIQUE_ORDER_ID");
paramMap.put("CUST_ID", "CUSTOMER_ID");
paramMap.put("CHANNEL_ID", "WAP");
paramMap.put("TXN_AMOUNT", "AMOUNT");
paramMap.put("WEBSITE", "WEBSTAGING"); // for staging environment, use "DEFAULT" for production
paramMap.put("INDUSTRY_TYPE_ID", "Retail");
paramMap.put("CALLBACK_URL", "CALLBACK_URL"); // the URL to which PayTM will send the payment response

PaytmOrder order = new PaytmOrder(paramMap);

service.initialize(order, null);

Replace the placeholders with the appropriate values from your merchant account.

  1. Start the payment transaction:
service.startPaymentTransaction(this, true, true, new PaytmPaymentTransactionCallback() {
    @Override
    public void onTransactionResponse(Bundle inResponse) {
        // Handle the payment response
    }

    @Override
    public void networkNotAvailable() {
        // Handle network error
    }

    @Override
    public void clientAuthenticationFailed(String inErrorMessage) {
        // Handle authentication error
    }

    @Override
    public void someUIErrorOccurred(String inErrorMessage) {
        // Handle UI error
    }

    @Override
    public void onErrorLoadingWebPage(int iniErrorCode, String inErrorMessage, String inFailingUrl) {
        // Handle web page loading error
    }

    @Override
    public void onBackPressedCancelTransaction() {
        // Handle transaction cancellation
    }

    @Override
    public void onTransactionCancel(String inErrorMessage, Bundle inResponse) {
        // Handle transaction cancellation
    }
});
  1. Handle the payment response in the onTransactionResponse() method:
@Override
public void onTransactionResponse(Bundle inResponse) {
    String status = inResponse.getString("STATUS");
    String message = inResponse.getString("RESPMSG");

    if (status != null && status.equals("TXN_SUCCESS")) {
        // Payment was successful
    } else {
        // Payment failed
    }
}

Step 6: Connect the PayTM activity to your app
Finally, you need to connect the PayTM activity to your e-commerce app. For example, you can add a button to the shopping cart screen and launch the PayTM activity when the user selects the payment option.

That’s it! You have now integrated the PayTM payment gateway into your Android e-commerce app. Remember to replace the placeholder values with your actual merchant credentials and customize the code according to your app’s requirements.

Please note that this guide provides a basic integration example. For a complete and detailed implementation, including error handling and additional features, you may need to refer to the official PayTM documentation or consult their support resources.

Slide transition between screens is common in Android applications. We can use the navigation components or a swipe-able view to create this transition. A common swipe-able view is ViewPager2. The ViewPager library has been around for quite a while.

Introduction

This view allows the developer to display views or fragments to the user in a swipe-able format. This feature is common in content display applications and in app setups.

ViewPager2 is often integrated with TabLayout. A TabLayout indicates the current page and allows a user to switch through pages.

Prerequisites

To follow through with this tutorial, you will need to:

  1. Have Android Studio installed.
  2. Have a basic knowledge of building Android applications.
  3. Have a basic understanding of Kotlin programming language.

Let’s get started!

  1. First, let’s set up the necessary dependencies in your app-level build.gradle file:
implementation 'androidx.viewpager2:viewpager2:1.0.0'
implementation 'com.google.android.material:material:1.4.0'
  1. Next, create a new layout file for your main activity (activity_main.xml). The layout will contain a TabLayout and a ViewPager2:
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <com.google.android.material.tabs.TabLayout
            android:id="@+id/tabLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimary"
            app:tabTextColor="@color/tab_text_color"
            app:tabSelectedTextColor="@color/tab_selected_text_color"
            app:tabIndicatorColor="@color/tab_indicator_color" />

    </com.google.android.material.appbar.AppBarLayout>

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/viewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="?attr/actionBarSize"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

</androidx.coordinatorlayout.widget.CoordinatorLayout>
  1. Create a new layout file for each of your blog fragments (fragment_blog.xml). Customize it to your needs:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <!-- Add your blog content views here -->

</LinearLayout>
  1. Create a new class for your ViewPager adapter (BlogPagerAdapter.java):
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.viewpager2.adapter.FragmentStateAdapter;

import java.util.List;

public class BlogPagerAdapter extends FragmentStateAdapter {
    private List<Fragment> fragments;

    public BlogPagerAdapter(@NonNull FragmentActivity fragmentActivity, List<Fragment> fragments) {
        super(fragmentActivity);
        this.fragments = fragments;
    }

    @NonNull
    @Override
    public Fragment createFragment(int position) {
        return fragments.get(position);
    }

    @Override
    public int getItemCount() {
        return fragments.size();
    }
}
  1. Finally, in your MainActivity, set up the TabLayout and ViewPager2:
import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.viewpager2.widget.ViewPager2;

import com.google.android.material.tabs.TabLayout;
import com.google.android.material.tabs.TabLayoutMediator;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private ViewPager2 viewPager;
    private TabLayout tabLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager = findViewById(R.id.viewPager);
        tabLayout = findViewById(R.id.tabLayout);

        List<Fragment> fragments = new ArrayList<>();
        fragments.add(new BlogFragment1());
        fragments.add(new BlogFragment2());
        fragments.add(new BlogFragment3());

        BlogPagerAdapter adapter = new BlogPagerAdapter(this, fragments);
        viewPager.setAdapter(adapter);

        new TabLayoutMediator(tabLayout, viewPager, (tab, position) -> {
            // Customize the tab names as per your requirement
            switch (position) {
                case 0:
                    tab.setText("Blog 1");
                    break;
                case 1:
                    tab.setText("Blog 2");
                    break;
                case 2:
                    tab.setText("Blog 3");
                    break;
            }
        }).attach();
    }
}

That’s it! You can now create separate fragments (BlogFragment1, BlogFragment2, etc.) and customize them for each blog page.

Note: Make sure to replace the colors and other resources with your own preferences in the XML files. Also, remember to register the MainActivity in your AndroidManifest.xml file.

This is a basic example to get you started. You can further enhance it with additional features and customization based on your requirements.