android:windowBackground property makes background black (Xamarin.Android) - image

Question

I want to make the following image to be the background for the entire Xamarin.Android application:
I reference the image in Base application theme in styles.xml :
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
.....
<item name="android:windowBackground">#drawable/ic_app_background_image</item>
.....
</style>
The background applies to all the application but the image has dark background:
Also the number 51 has some strange things around it.
When I set the android:background="#drawable/ic_app_background_image" to the most outer LinearLayout of an activity it works fine, it shows the screen like that:
How can I fix the android:windowBackground property setting the background to black issue so I don't have to put android:background="#drawable/ic_app_background_image" in the LinearLayout of every activity?

Answer 1

You can try following method:
1.Create new file name as bg.xml in drawable folder (bg.xml)
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<color android:color="#color/splash_background"/>
</item>
<item>
<bitmap
android:src="#drawable/splash_logo"
android:tileMode="disabled"
android:gravity="center"/>
</item>
</layer-list>
2.define background color in colors.xml
<color name="window_background">#F5F5F5</color>
<color name="splash_background">#FFFFFF</color>
3.define new style MyTheme.Splash in style.xml and use the bg in item android:windowBackground
<style name="MyTheme.Splash" parent ="Theme.AppCompat.Light.NoActionBar">
<item name="android:windowBackground">#drawable/bg</item>
<item name="android:windowNoTitle">true</item>
<item name="android:windowFullscreen">false</item>
<item name="android:windowContentOverlay">#null</item>
<item name="android:windowActionBar">true</item>
</style>
4.Usage in Activity
[Activity(Theme = "#style/MyTheme.Splash", MainLauncher = true, NoHistory = true)]
public class SplashActivity : AppCompatActivity
{
// other code
}
Update:
If you want to apply this style to all activities, you can just add the following code to your Base application theme. And we don't need to set for each activity. For example:
<!-- Base application theme. parent="Theme.AppCompat.Light.DarkActionBar" -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">#color/colorPrimary</item>
<item name="colorPrimaryDark">#color/colorPrimaryDark</item>
<item name="colorAccent">#color/colorAccent</item>
<item name="android:windowBackground">#drawable/bg</item>
<item name="android:windowNoTitle">true</item>
<item name="android:windowFullscreen">false</item>
<item name="android:windowContentOverlay">#null</item>
<item name="android:windowActionBar">true</item>
</style>
The result is:
For more details, you can check: https://learn.microsoft.com/en-us/xamarin/android/user-interface/splash-screen