OnReceiveContentListener

public interface OnReceiveContentListener

androidx.core.view.OnReceiveContentListener


Listener for apps to implement handling for insertion of content. Content may be both text and non-text (plain/styled text, HTML, images, videos, audio files, etc).

This listener can be attached to different types of UI components using ViewCompat.setOnReceiveContentListener(View, String[], OnReceiveContentListener).

Here is a sample implementation that handles content URIs and delegates the processing for text and everything else to the platform:

 // (1) Define the listener
 public class MyReceiver implements OnReceiveContentListener {
     public static final String[] MIME_TYPES = new String[] {"image/*", "video/*"};

     @Override
     public ContentInfoCompat onReceiveContent(View view, ContentInfoCompat payload) {
         // Split the incoming content into two groups: content URIs and everything else.
         // This way we can implement custom handling for URIs and delegate the rest.
         Pair<ContentInfoCompat, ContentInfoCompat> split = payload.partition(
                 item -> item.getUri() != null);
         ContentInfoCompat uriContent = split.first;
         ContentInfoCompat remaining = split.second;
         if (uriContent != null) {
             ClipData clip = uriContent.getClip();
             for (int i = 0; i < clip.getItemCount(); i++) {
                 Uri uri = clip.getItemAt(i).getUri();
                 // ... app-specific logic to handle the URI ...
             }
         }
         // Return anything that we didn't handle ourselves. This preserves the default platform
         // behavior for text and anything else for which we are not implementing custom handling.
         return remaining;
     }
 }

 // (2) Register the listener
 public class MyActivity extends Activity {
     @Override
     public void onCreate(Bundle savedInstanceState) {
         // ...

         AppCompatEditText myInput = findViewById(R.id.my_input);
         ViewCompat.setOnReceiveContentListener(myInput, MyReceiver.MIME_TYPES, new MyReceiver());
     }
 }
 

Summary

Public methods

abstract ContentInfoCompat onReceiveContent(View view, ContentInfoCompat payload)

Receive the given content.

Public methods

onReceiveContent

public abstract ContentInfoCompat onReceiveContent (View view, 
                ContentInfoCompat payload)

Receive the given content.

Implementations should handle any content items of interest and return all unhandled items to preserve the default platform behavior for content that does not have app-specific handling. For example, an implementation may provide handling for content URIs (to provide support for inserting images, etc) and delegate the processing of text to the platform to preserve the common behavior for inserting text. See the class javadoc for a sample implementation and see ContentInfoCompat.partition(Predicate) for a convenient way to split the passed-in content.

Handling different content

  • Text. The passed-in text should overwrite the current selection or be inserted at the current cursor position if there is no selection.
  • Non-text content (e.g. images). The content may be inserted inline if the widget supports this, or it may be added as an attachment (could potentially be shown in a completely separate view).

URI permissions

Read permissions are granted automatically by the platform for any content URIs in the payload passed to this listener. Permissions are transient and will be released automatically by the platform.

Processing of content should normally be done in a service or activity. For long-running processing, using androidx.work.WorkManager is recommended. When implementing this, permissions should be extended to the target service or activity by passing the content using Intent.setClipData and setting the flag FLAG_GRANT_READ_URI_PERMISSION.

Alternatively, if using a background thread within the current context to process the content, a reference to the payload object should be maintained to ensure that permissions are not revoked prematurely.

Parameters
view View: The view where the content insertion was requested.

payload ContentInfoCompat: The content to insert and related metadata. The payload may contain multiple items and their MIME types may be different (e.g. an image item and a text item). The payload may also contain items whose MIME type is not in the list of MIME types specified when setting the listener. For those items, the listener may reject the content (defer to the default platform behavior) or execute some other fallback logic (e.g. show an appropriate message to the user).

Returns
ContentInfoCompat The portion of the passed-in content whose processing should be delegated to the platform. Return null if all content was handled in some way. Actual insertion of the content may be processed asynchronously in the background and may or may not succeed even if this method returns null. For example, an app may end up not inserting an item if it exceeds the app's size limit for that type of content.