Image keyboard support

Users often want to communicate using emoji, stickers, and other kinds of rich content. In previous versions of Android, soft keyboards—also known as input method editors, or IMEs—could send only Unicode emoji to apps. For rich content, apps built app-specific APIs that couldn't be used in other apps or used workarounds like sending images through simple share action or the clipboard.

Starting with Android 7.1 (API level 25), the Android SDK includes the Commit Content API, which provides a universal way for IMEs to send images and other rich content directly to a text editor in an app. The API is also available in the v13 Support Library as of revision 25.0.0. We recommend using the Support Library because it contains helper methods that simplify implementation.

With this API, you can build messaging apps that accept rich content from any keyboard as well as keyboards that can send rich content to any app. The Google Keyboard and apps like Messages by Google support the Commit Content API in Android 7.1, as shown in figure 1.

This document shows how to implement the Commit Content API in both IMEs and apps.

How it works

Keyboard image insertion requires participation from the IME and the app. The following sequence describes each step in the image insertion process:

1. When the user taps an EditText, the editor sends a list of MIME content types that it accepts in EditorInfo.contentMimeTypes.

2. The IME reads the list of supported types and displays content in the soft keyboard that the editor can accept.

3. When the user selects an image, the IME calls commitContent() and sends an InputContentInfo to the editor. The commitContent() call is analogous to the commitText() call, but for rich content. InputContentInfo contains an URI that identifies the content in a content provider.

This process is depicted in figure 2:

Add image support to apps

To accept rich content from IMEs, an app must tell IMEs what content types it accepts and specify a callback method that is executed when content is received. The following example demonstrates how to create an EditText that accepts PNG images:

var editText: EditText = object : EditText(this) {
    override fun onCreateInputConnection(outAttrs: EditorInfo): InputConnection {
        var ic = super.onCreateInputConnection(outAttrs)
        EditorInfoCompat.setContentMimeTypes(outAttrs, arrayOf("image/png"))
        val mimeTypes = ViewCompat.getOnReceiveContentMimeTypes(this)
        if (mimeTypes != null) {
            EditorInfoCompat.setContentMimeTypes(outAttrs, mimeTypes)
            ic = InputConnectionCompat.createWrapper(this, ic, outAttrs)
        }
        return ic
    }
}

EditText editText = new EditText(this) {
    @Override
    public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
        InputConnection ic = super.onCreateInputConnection(outAttrs);
        EditorInfoCompat.setContentMimeTypes(outAttrs, new String[]{"image/png"});
        String[] mimeTypes = ViewCompat.getOnReceiveContentMimeTypes(this);
        if (mimeTypes != null) {
            EditorInfoCompat.setContentMimeTypes(outAttrs, mimeTypes);
            ic = InputConnectionCompat.createWrapper(this, ic, outAttrs);
        }
        return ic;
    }
};

The following is further explanation:

• This example uses the Support Library, so there are some references to android.support.v13.view.inputmethod instead of android.view.inputmethod.

• This example creates an EditText and overrides its onCreateInputConnection(EditorInfo) method to modify the InputConnection. The InputConnection is the communication channel between an IME and the app that is receiving its input.

• The call super.onCreateInputConnection() preserves the built-in behavior—sending and receiving text—and gives you a reference to the InputConnection.

• setContentMimeTypes() adds a list of supported MIME types to the EditorInfo. Call super.onCreateInputConnection() before setContentMimeTypes().

• callback is executed whenever the IME commits content. The method onCommitContent() has a reference to InputContentInfoCompat, which contains a content URI.

  • Request and release permissions if your app is running on API level 25 or higher and the INPUT_CONTENT_GRANT_READ_URI_PERMISSION flag is set by the IME. Otherwise, you already have access to the content URI because it is granted by the IME or because the content provider doesn't restrict access. For more information, see Add image support to IMEs.

• createWrapper() wraps the InputConnection, the modified EditorInfo, and the callback into a new InputConnection and returns it.

The following are recommended practices:

• Editors that don't support rich content don't call setContentMimeTypes(), and they leave their EditorInfo.contentMimeTypes set to null.

• Editors ignore the content if the MIME type specified in InputContentInfo doesn't match any of the types they accept.

• Rich content doesn't affect and isn't affected by the position of the text cursor. Editors can ignore cursor position when working with content.

• In the editor's OnCommitContentListener.onCommitContent() method, you can return true asynchronously, even before loading the content.

• Unlike text, which can be edited in the IME before being committed, rich content is committed immediately. If you want to let users edit or delete content, implement the logic yourself.

To test your app, make sure your device or emulator has a keyboard that can send rich content. You can use the Google Keyboard in Android 7.1 or higher.

Add image support to IMEs

IMEs that want to send rich content to apps must implement the Commit Content API, as shown in the following example:

• Override onStartInput() or onStartInputView() and read the list of supported content types from the target editor. The following code snippet shows how to check whether the target editor accepts GIF images.

override fun onStartInputView(editorInfo: EditorInfo, restarting: Boolean) {
    val mimeTypes: Array<String> = EditorInfoCompat.getContentMimeTypes(editorInfo)

    val gifSupported: Boolean = mimeTypes.any {
        ClipDescription.compareMimeTypes(it, "image/gif")
    }

    if (gifSupported) {
        // The target editor supports GIFs. Enable the corresponding content.
    } else {
        // The target editor doesn't support GIFs. Disable the corresponding
        // content.
    }
}

@Override
public void onStartInputView(EditorInfo info, boolean restarting) {
    String[] mimeTypes = EditorInfoCompat.getContentMimeTypes(editorInfo);

    boolean gifSupported = false;
    for (String mimeType : mimeTypes) {
        if (ClipDescription.compareMimeTypes(mimeType, "image/gif")) {
            gifSupported = true;
        }
    }

    if (gifSupported) {
        // The target editor supports GIFs. Enable the corresponding content.
    } else {
        // The target editor doesn't support GIFs. Disable the corresponding
        // content.
    }
}

• Commit content to the app when the user selects an image. Avoid calling commitContent() when there is any text being composed, because it might cause the editor to lose focus. The following code snippet shows how to commit a GIF image.

// Commits a GIF image.

// @param contentUri = Content URI of the GIF image to be sent.
// @param imageDescription = Description of the GIF image to be sent.

fun commitGifImage(contentUri: Uri, imageDescription: String) {
    val inputContentInfo = InputContentInfoCompat(
            contentUri,
            ClipDescription(imageDescription, arrayOf("image/gif")),
            null
    )
    val inputConnection = currentInputConnection
    val editorInfo = currentInputEditorInfo
    var flags = 0
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N_MR1) {
        flags = flags or InputConnectionCompat.INPUT_CONTENT_GRANT_READ_URI_PERMISSION
    }
    InputConnectionCompat.commitContent(inputConnection, editorInfo, inputContentInfo, flags, null)
}

// Commits a GIF image.

// @param contentUri = Content URI of the GIF image to be sent.
// @param imageDescription = Description of the GIF image to be sent.

public static void commitGifImage(Uri contentUri, String imageDescription) {
    InputContentInfoCompat inputContentInfo = new InputContentInfoCompat(
            contentUri,
            new ClipDescription(imageDescription, new String[]{"image/gif"}),
            null
    );
    InputConnection inputConnection = getCurrentInputConnection();
    EditorInfo editorInfo = getCurrentInputEditorInfo();
    Int flags = 0;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N_MR1) {
        flags |= InputConnectionCompat.INPUT_CONTENT_GRANT_READ_URI_PERMISSION;
    }
    InputConnectionCompat.commitContent(
            inputConnection, editorInfo, inputContentInfo, flags, null);
}

As an IME author, you most likely have to implement your own content provider to respond to content URI requests. The exception is if your IME supports content from existing content providers like MediaStore. For information on building content providers, see the content provider and file provider documentation.

If you are building your own content provider, we recommend you don't export it by setting android:exported to false. Instead, enable permission granting in the provider by setting android:grantUriPermission to true. Then, your IME can grant permissions to access the content URI when the content is committed. There are two ways to do this:

• On Android 7.1 (API level 25) and higher, when calling commitContent(), set the flag parameter to INPUT_CONTENT_GRANT_READ_URI_PERMISSION. Then, the InputContentInfo object that the app receives can request and release temporary read permissions by calling requestPermission() and releasePermission().

• On Android 7.0 (API level 24) and lower, INPUT_CONTENT_GRANT_READ_URI_PERMISSION is ignored, so manually grant permission to the content. One way to do this is with grantUriPermission(), but you can implement your own mechanism that satisfies your own requirements.

To test your IME, make sure your device or emulator has an app that can receive rich content. You can use the Google Messenger app in Android 7.1 or higher.