Enhance your widget

This page includes details for optional widget enhancements that are available starting in Android 12 (API level 31). These features are optional, but they're straightforward to implement and improve your users' widget experience.

Use dynamic colors

Starting in Android 12, a widget can use the device theme colors for buttons, backgrounds, and other components. This provides smoother transitions and consistency across different widgets.

There are two ways to achieve dynamic colors:

• Use the system's default theme (@android:style/Theme.DeviceDefault.DayNight) in the root layout.

• Use the Material 3 theme (Theme.Material3.DynamicColors.DayNight) from the Material Components for Android library, available starting in Material Components for Android v1.6.0.

Once the theme is set in the root layout, you can use common color attributes in the root or any of its children to pick up the dynamic colors.

Some examples of color attributes you can use are the following:

• ?attr/primary
• ?attr/primaryContainer
• ?attr/onPrimary
• ?attr/onPrimaryContainer

In the following example using the Material 3 theme, the device's theme color is "purplish." The accent color and widget background adapt for light and dark modes, as shown in figures 1 and 2.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="?attr/colorPrimaryContainer"
  android:theme="@style/Theme.Material3.DynamicColors.DayNight">

  <ImageView
    ...
    app:tint="?attr/colorPrimaryContainer"
    android:src="@drawable/ic_partly_cloudy" />

    <!-- Other widget content. -->

</LinearLayout>

Backward compatibility for dynamic colors

Dynamic colors are only available in devices running Android 12 or higher. To provide a custom theme for lower versions, create a default theme with your custom colors and a new qualifier (values-v31) using the default theme attributes.

Here is an example using the Material 3 theme:

<resources>
  <style name="MyWidgetTheme" parent="Theme.Material3.DynamicColors.DayNight">
    <!-- Override default colorBackground attribute with custom color. -->
    <item name="android:colorBackground">@color/my_background_color</item>

    <!-- Add other colors/attributes. -->

  </style>
</resources>

<resources>
  <!-- Do not override any color attribute. -->
  <style name="MyWidgetTheme" parent="Theme.Material3.DynamicColors.DayNight" />
</resources>

<resources>
  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    ...
    android:background="?android:attr/colorBackground"
    android:theme="@style/MyWidgetTheme" />
</resources>

Enable voice support

App Actions let Google Assistant display widgets in response to relevant user voice commands. By configuring your widget to respond to built-in intents (BIIs), your app can proactively display widgets on Assistant surfaces such as Android and Android Auto. Users have the option to pin widgets displayed by Assistant to their launcher, encouraging future engagement.

For example, you can configure the workout summary widget for your exercise app to fulfill the user voice commands that trigger the GET_EXERCISE_OBSERVATION BII. Assistant proactively displays your widget when users trigger this BII by making requests like, "Hey Google, how many miles did I run this week on ExampleApp?"

There are dozens of BIIs covering several categories of user interaction, letting almost any Android app enhance their widgets for voice. To get started, see Integrate App Actions with Android widgets.

Improve your app's widget picker experience

Android 12 lets you improve the widget picker experience for your app by adding dynamic widget previews and widget descriptions.

Add scalable widget previews to the widget picker

Starting in Android 12, the widget preview displayed in the widget picker is scalable. You provide it as an XML layout set to the widget's default size. Previously, the widget preview was a static drawable resource, in some cases leading to previews inaccurately reflecting how widgets appear when they are added to the home screen.

To implement scalable widget previews, use the previewLayout attribute of the appwidget-provider element to provide an XML layout instead:

<appwidget-provider
    android:previewLayout="@layout/my_widget_preview">
</appwidget-provider>

We recommend using the same layout as the actual widget, with realistic default or test values. Most apps use the same previewLayout and initialLayout. For guidance on creating accurate preview layouts, see the following section in this page.

We recommend specifying both the previewLayout and previewImage attributes, so that your app can fall back to using previewImage if the user's device doesn't support previewLayout. The previewLayout attribute takes precedence over the previewImage attribute.

Recommended approaches for building accurate previews

To implement scalable widget previews, use the previewLayout attribute of the appwidget-provider element to provide an XML layout:

<appwidget-provider
    ...
    android:previewLayout="@layout/my_widget_preview">
</appwidget-provider>

To display an accurate preview, you can directly provide the actual widget layout with default values by completing the following steps:

• Setting android:text="@string/my_widget_item_fake_1" for TextView elements.

• Setting a default or placeholder image or icon, such as android:src="@drawable/my_widget_icon", for ImageView components.

Without default values, the preview might show incorrect or empty values. An important benefit of this approach is that you can provide localized preview content.

For recommended approaches for more complex previews that contain ListView, GridView, or StackView, see Build accurate previews that include dynamic items for details.

Backward compatibility with scalable widget previews

To let widget pickers on Android 11 (API level 30) or lower show previews of your widget, specify the previewImage attribute.

If you change the widget's appearance, update the preview image.

Add a description for your widget

Starting in Android 12, provide a description for the widget picker to display for your widget.

Provide a description for your widget using the description attribute of the <appwidget-provider> element:

<appwidget-provider
    android:description="@string/my_widget_description">
</appwidget-provider>

You can use the descriptionRes attribute on previous versions of Android, but it is ignored by the widget picker.

Enable smoother transitions

Starting in Android 12, launchers provide a smoother transition when a user launches your app from a widget.

To enable this improved transition, use @android:id/background or android.R.id.background to identify your background element:

// Top-level layout of the widget.
<LinearLayout
    android:id="@android:id/background">
</LinearLayout>

Your app can use @android:id/background on previous versions of Android without breaking, but it is ignored.

Use runtime modification of RemoteViews

Starting in Android 12, you can take advantage of several RemoteViews methods that provide for runtime modification of RemoteViews attributes. See the RemoteViews API reference for the full list of added methods.

The following code example shows how to use a few of these methods.

// Set the colors of a progress bar at runtime.
remoteView.setColorStateList(R.id.progress, "setProgressTintList", createProgressColorStateList())

// Specify exact sizes for margins.
remoteView.setViewLayoutMargin(R.id.text, RemoteViews.MARGIN_END, 8f, TypedValue.COMPLEX_UNIT_DP)

// Set the colors of a progress bar at runtime.
remoteView.setColorStateList(R.id.progress, "setProgressTintList", createProgressColorStateList());

// Specify exact sizes for margins.
remoteView.setViewLayoutMargin(R.id.text, RemoteViews.MARGIN_END, 8f, TypedValue.COMPLEX_UNIT_DP);