<!--
  ~ Copyright (C) 2021 The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~ http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->
<!--
Having styles for v21 because specifying android:attr/colorBackground used in the drawables
requires API level 21
-->
<resources>
    <style name="Widget.AppWidget.AppWidget.Container" parent="android:Widget">
        <item name="android:padding">?attr/appWidgetPadding</item>
        <item name="android:background">@drawable/app_widget_background</item>
    </style>

    <style name="Widget.AppWidget.AppWidget.InnerView" parent="android:Widget">
        <item name="android:padding">?attr/appWidgetPadding</item>
        <item name="android:background">@drawable/app_widget_inner_view_background</item>
    </style>

    <style name="Widget.AppWidget.ImageView.WeatherIcon" parent="android:Widget">
        <item name="android:tint">?android:attr/colorAccent</item>
    </style>
</resources>
<!--
  ~ Copyright (C) 2021 The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~ http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->
<!--
Having styles for v21 because specifying android:attr/colorBackground used in the drawables
requires API level 21
-->
<resources>
    <style name="Widget.AppWidget.AppWidget.Container" parent="android:Widget">
        <item name="android:id">@android:id/background</item>
        <item name="android:padding">?attr/appWidgetPadding</item>
        <item name="android:background">@drawable/app_widget_background</item>
    </style>

    <style name="Widget.AppWidget.AppWidget.InnerView" parent="android:Widget">
        <item name="android:padding">?attr/appWidgetPadding</item>
        <item name="android:background">@drawable/app_widget_inner_view_background</item>
    </style>

    <style name="Widget.AppWidget.ImageView.WeatherIcon" parent="android:Widget">
        <item name="android:tint">?android:attr/colorAccent</item>
    </style>
</resources>
Add android:id for the style of the v21 variant
Add android:id for the style of the v21 variant
