Detailed explanation of how Android quickly adapts to dark mode

Direct code

public class DarkModeUtils {

    public static final String KEY_CURRENT_MODEL = "night_mode_state_sp";

    private static int getNightModel(Context context) {
        SharedPreferences sp = context.getSharedPreferences(KEY_CURRENT_MODEL, Context.MODE_PRIVATE);
        return sp.getInt(KEY_CURRENT_MODEL, AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
    }

    public static void setNightModel(Context context, int nightMode) {
        SharedPreferences sp = context.getSharedPreferences(KEY_CURRENT_MODEL, Context.MODE_PRIVATE);
        sp.edit().putInt(KEY_CURRENT_MODEL, nightMode).apply();
    }

    /**
     * ths method should be called in Application onCreate method
     *
     * @param application application
     */
    public static void init(Application application) {
        int nightMode = getNightModel(application);
        AppCompatDelegate.setDefaultNightMode(nightMode);
    }

    /**
     *  Apply night mode 
     */
    public static void applyNightMode(Context context) {
        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
        setNightModel(context, AppCompatDelegate.MODE_NIGHT_YES);
    }

    /**
     *  Apply daytime mode 
     */
    public static void applyDayMode(Context context) {
        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
        setNightModel(context, AppCompatDelegate.MODE_NIGHT_NO);
    }

    /**
     *  Dynamic switching is required when following system topics 
     */
    public static void applySystemMode(Context context) {
        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
        setNightModel(context, AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
    }

    /**
     *  Judge App Are you currently in Diablo Mode 
     *
     * @param context  Context 
     * @return  Return 
     */
    public static boolean isDarkMode(Context context) {
        int nightMode = getNightModel(context);
        if (nightMode == AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM) {
            int applicationUiMode = context.getResources().getConfiguration().uiMode;
            int systemMode = applicationUiMode & Configuration.UI_MODE_NIGHT_MASK;
            return systemMode == Configuration.UI_MODE_NIGHT_YES;
        } else {
            return nightMode == AppCompatDelegate.MODE_NIGHT_YES;
        }
    }

}

Use process

Obviously, this is the way to switch Diablo mode. You must choose the Diablo style that adapts to App before calling.

How to adapt

Color resource
Create a new values-night folder and replace all color values used in the page with those in Diablo mode. Picture resource
Create a new mipmap-night/drawable-night folder and replace the picture and style resources used in the page with their counterparts in Diablo mode. Status bar
The last method isDarkMode in the code above determines what color of the status bar is displayed. It is best to operate in BaseActivity, otherwise Activity is very troublesome. Call
Call the method above to switch the dark mode of App. Points to note are as follows:

Need attention

androidx can be called directly. To use on support and switch Diablo Mode in Activity, you need to call the activity. recreate () method dynamically under 1. See the following source code for specific reasons:

androidx version:

/**
     * Sets the default night mode. This is the default value used for all components, but can
     * be overridden locally via {@link #setLocalNightMode(int)}.
     *
     * <p>This is the primary method to control the DayNight functionality, since it allows
     * the delegates to avoid unnecessary recreations when possible.</p>
     *
     * <p>If this method is called after any host components with attached
     * {@link AppCompatDelegate}s have been 'started', a {@code uiMode} configuration change
     * will occur in each. This may result in those components being recreated, depending
     * on their manifest configuration.</p>
     *
     * <p>Defaults to {@link #MODE_NIGHT_FOLLOW_SYSTEM}.</p>
     *
     * @see #setLocalNightMode(int)
     * @see #getDefaultNightMode()
     */
    public static void setDefaultNightMode(@NightMode int mode) {
        switch (mode) {
            case MODE_NIGHT_NO:
            case MODE_NIGHT_YES:
            case MODE_NIGHT_FOLLOW_SYSTEM:
            case MODE_NIGHT_AUTO_TIME:
            case MODE_NIGHT_AUTO_BATTERY:
                if (sDefaultNightMode != mode) {
                    sDefaultNightMode = mode;
                    applyDayNightToActiveDelegates();
                }
                break;
            default:
                Log.d(TAG, "setDefaultNightMode() called with an unknown mode");
                break;
        }
    }

support version:

public static void setDefaultNightMode(int mode) {
        switch(mode) {
        case -1:
        case 0:
        case 1:
        case 2:
            sDefaultNightMode = mode;
            break;
        default:
            Log.d("AppCompatDelegate", "setDefaultNightMode() called with an unknown mode");
        }
    }

After comparison, we can find that after androidx switches dark mode, it actively calls apply method to rebuild Activity. But not on support, it's just assignment. Therefore, using the support version requires calling the activity. recreate () method yourself.

Summarize