Insert content text input client

Added an insertContent method to the TextInputClient interface to allow Android's image keyboard feature to insert content into a Flutter TextField.

As of Android 7.1, IMEs (input method editors or virtual keyboards) can send images and rich content into a text editor. This allows users to insert gifs, stickers, or context-aware rich content into a text field.

When the user inserts rich content in the IME, the platform sends a TextInputClient.commitContent channel message, notifying the Dart code that the IME inserted rich content. The channel message contains the mime type, URI, and bytedata for the inserted content in JSON form.

If you implemented the TextInputClient interface earlier, override insertContent to either support rich content insertion or provide an empty implementation.

To migrate, implement insertContent.

Code before migration:

class MyCustomTextInputClient implements TextInputClient {
  // ...
}

Code after migration:

class MyCustomTextInputClient implements TextInputClient {
  // ...
  @override
  void insertContent() {
    // ...
  }
  // ...
}

Your implementation of TextInputClient might not require the ability to receive rich content inserted from the IME. In that case, you can leave the implementation of insertContent empty with no consequences.

class MyCustomTextInputClient implements TextInputClient {
  // ...
  @override
  void insertContent() {}
  // ...
}

As an alternative, you can use a similar implementation to the default TextInputClient. To learn how to do this, check out the insertContent implementation.

To prevent breaking changes to an interface, use with TextInputClient rather than implements TextInputClient.

Landed in version: 3.8.0-1.0.pre
In stable release: 3.10.0

API documentation:

• TextInputClient

Relevant issue:

• Issue 20796

Relevant PRs:

• 24224: Support Image Insertion on Android (engine)
• 97437: Support Image Insertion on Android