Using Android's registerForActivityResult

The registerForActivityResult method is a part of the Activity Result API, which was introduced as part of Android Jetpack. This API provides a more modular and consistent way to manage the flow of information between activities and fragments. It simplifies the process of dealing with different types of user interactions, such as picking a file, taking a picture, or requesting permissions.

Example: Requesting Permission using registerForActivityResult

Let's consider an example where you want to request a runtime permission, such as accessing the device's camera. With registerForActivityResult, you can streamline this process by defining a contract for the permission request and then handling the result in a concise and readable manner.

First, create a new instance of the ActivityResultContracts.RequestPermission class, passing in the permission you want to request:

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1val requestPermissionLauncher = registerForActivityResult(ActivityResultContracts.RequestPermission()) { isGranted: Boolean ->
2    if (isGranted) {
3        // Permission is granted, continue with the desired operation
4    } else {
5        // Handle the scenario where the permission is denied
6    }
7}

Next, when you are ready to request the permission, you can use the requestPermissionLauncher to launch the permission request flow:

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1requestPermissionLauncher.launch(Manifest.permission.CAMERA)

Example: Getting a Result from Another Activity using registerForActivityResult

Another common use case is to receive a result from another activity, such as retrieving an image from the device's gallery. With registerForActivityResult, you can easily define a contract for this interaction and handle the result seamlessly.

Suppose you want to fetch an image from the device's gallery. You can create a contract using the ActivityResultContracts.GetContent() class:

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1val getContent = registerForActivityResult(ActivityResultContracts.GetContent()) { uri: Uri? ->
2    // Handle the obtained content URI
3    imageView.setImageURI(uri)
4}

When you're ready to trigger the image selection process, you can simply call the launch method on getContent:

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1getContent.launch("image/*")

In Closing

By leveraging this modern approach, you can simplify the process of managing user interactions and streamline your project/codebase. Whether it's requesting permissions, capturing images, or handling other activity results, registerForActivityResult offers a cleaner and more organized way to incorporate these functionalities into your Android apps.