XML configuration data

The time interval for the refresh action (and other properties like minimum dimension) are described in xml file "my_widget_info.xml" which is stored in the resource folder of your project:

<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
    android:minWidth="120dp"
    android:minHeight="10dp"
    android:updatePeriodMillis="300000"
    android:initialLayout="@layout/my_widget"
    android:resizeMode="horizontal|vertical"
    android:widgetCategory="home_screen|keyguard"
    android:previewImage="@drawable/calendar_edit_icon">
</appwidget-provider>

All needed information about your app widget package and the reference to the widget info from above is contained in the manifest file "AndroidManifest.xml":

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="eu.fahrnholz.gerald.gfacontrolwidget">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

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

</manifest>