Declare the AppWidgetProvider class in your application’s AndroidManifest.xml file. For example:

<receiver android:name="ExampleAppWidgetProvider" >
<intent-filter>
    <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
<meta-data android:name="android.appwidget.provider"
           android:resource="@xml/example_appwidget_info" />
</receiver>