Create an app widget with Glance

The following sections describe how to create a simple app widget with Glance.

Declare the AppWidget in the Manifest

After completing the setup steps, declare the AppWidget and its metadata in your app.

1. Register the provider of the app widget in your AndroidManifest.xml file and the associated metadata file:

<receiver android:name=".glance.MyReceiver"
    android:exported="true">
    <intent-filter>
        <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
    </intent-filter>
    <meta-data
        android:name="android.appwidget.provider"
        android:resource="@xml/my_app_widget_info" />
</receiver>
AndroidManifest.xml

1. Extend the AppWidget receiver from GlanceAppWidgetReceiver:

class MyAppWidgetReceiver : GlanceAppWidgetReceiver() {
    override val glanceAppWidget: GlanceAppWidget = TODO("Create GlanceAppWidget")
}
GlanceSnippets.kt

Add the AppWidgetProviderInfo metadata

Next, follow this step to add the AppWidgetProviderInfo metadata:

1. Follow the Create a simple widget guide to create and define the app widget info in the @xml/my_app_widget_info file.

   The only difference for Glance is that there is no initialLayout XML, but you must define one. You can use the predefined loading layout provided in the library:

<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
    android:initialLayout="@layout/glance_default_loading_layout">
</appwidget-provider>
my_app_widget_info.xml

Define GlanceAppWidget

1. Create a new class that extends from GlanceAppWidget and overrides the provideGlance method. This is the method where you can load data that is needed to render your widget:

class MyAppWidget : GlanceAppWidget() {

    override suspend fun provideGlance(context: Context, id: GlanceId) {

        // In this method, load data needed to render the AppWidget.
        // Use `withContext` to switch to another thread for long running
        // operations.

        provideContent {
            // create your AppWidget here
            Text("Hello World")
        }
    }
}
GlanceSnippets.kt

1. Instantiate it in the glanceAppWidget on your GlanceAppWidgetReceiver:

class MyAppWidgetReceiver : GlanceAppWidgetReceiver() {

    // Let MyAppWidgetReceiver know which GlanceAppWidget to use
    override val glanceAppWidget: GlanceAppWidget = MyAppWidget()
}
GlanceSnippets.kt

You've now configured an AppWidget using Glance.

Create UI

The following snippet demonstrates how to create the UI:

/* Import Glance Composables
 In the event there is a name clash with the Compose classes of the same name,
 you may rename the imports per https://kotlinlang.org/docs/packages.html#imports
 using the `as` keyword.

import androidx.glance.Button
import androidx.glance.layout.Column
import androidx.glance.layout.Row
import androidx.glance.text.Text
*/
class MyAppWidget : GlanceAppWidget() {

    override suspend fun provideGlance(context: Context, id: GlanceId) {
        // Load data needed to render the AppWidget.
        // Use `withContext` to switch to another thread for long running
        // operations.

        provideContent {
            // create your AppWidget here
            GlanceTheme {
                MyContent()
            }
        }
    }

    @Composable
    private fun MyContent() {
        Column(
            modifier = GlanceModifier.fillMaxSize()
                .background(GlanceTheme.colors.background),
            verticalAlignment = Alignment.Top,
            horizontalAlignment = Alignment.CenterHorizontally
        ) {
            Text(text = "Where to?", modifier = GlanceModifier.padding(12.dp))
            Row(horizontalAlignment = Alignment.CenterHorizontally) {
                Button(
                    text = "Home",
                    onClick = actionStartActivity<MainActivity>()
                )
                Button(
                    text = "Work",
                    onClick = actionStartActivity<MainActivity>()
                )
            }
        }
    }
}
GlanceSnippets.kt

The preceding code sample does the following:

• In the top level Column, items are placed vertically one after each other.
• The Column expands its size to match the available space (via the GlanceModifier and aligns its content to the top (verticalAlignment) and centers it horizontally (horizontalAlignment).
• The Column's content is defined using the lambda. The order matters.
  • The first item in the Column is a Text component with 12.dp of padding.
  • The second item is a Row, where items are placed horizontally one after each other, with two Buttons centered horizontally (horizontalAlignment). The final display depends on the available space. The following image is an example of what it may look like:

You can change the alignment values or apply different modifier values (such as padding) to change the placement and size of the components. See the reference documentation for a full list of components, parameters, and available modifiers for each class.