windowbackground 不适用于深色和浅色主题

Question

I have a theme that user can choose light or dark, everything work fine but, there are 2 problems:

1. When I open the app [in dark/light theme ], a white page is displayed first, then the application uses a dark theme
2. When I change the theme, a black screen appears first

I tried to change the background but did not work, I changed the color of it and also I used drawable shape. Anyway, it not work and use one color for both.

style.xml

 <style name="AppTheme" parent="Theme.MaterialComponents.DayNight.NoActionBar"/>

values/themes.xml

<style name="Theme.MaterialComponents.DayNight.NoActionBar"
        parent="Theme.MaterialComponents.Light.NoActionBar">

    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="android:windowBackground">@drawable/window_background</item>
</style>

values-night/themes.xml

<style name="Theme.MaterialComponents.DayNight.NoActionBar"
        parent="Theme.MaterialComponents.NoActionBar">

    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/TabBackground</item>
    <item name="colorAccent">@color/green_inactive</item>
    <item name="android:windowBackground">@drawable/window_background_dark</item>

</style>

windows_background

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
    <solid android:color="#64b5f6"/>
</shape>

windows_background_dark

Similar to the above code, only the color is different

and this is how I load theme

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (Prefs.getIsDarkMode(getApplicationContext()))
        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
    else
        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);

    setContentView(R.layout.activity_main);
}

Answer 1

There is no need to create seperate file for background.You can do that in the dark and night xml files itself.check out the below link.I have implemented night mode through this video.

https://youtu.be/-qsHE3TpJqw If you have any problem in implementation,drop a message.