[Android App]Screen flickers when I switch dark mode

Question

I'm currently creating my own application with Android Studio. In this app, I want to create a switch, that changes to dark mode and back.

In the MainActivity.java I'm using the following code

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Switch;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.app.AppCompatDelegate;

public class MainActivity extends AppCompatActivity {
    private Button button;
    private Switch aSwitch;

    public static final String MyPREFERENCES = "nightModePrefs";
    public static final String KEY_ISNIGHTMODE = "isNightMode";
    SharedPreferences sharedpreferences;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button feed = findViewById(R.id.feed);

        sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);

        aSwitch = findViewById(R.id.day_night);

        checkNightModeActivated();

        aSwitch.setOnCheckedChangeListener((buttonView, isChecked) -> {
            if (isChecked) {
                AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
                saveNightModeState(true);
                recreate();
            }else{
                AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
                saveNightModeState(true);
                recreate();
            }
        });


        feed.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MainActivity.this, Newsfeed.class));
            }
        });

    }

    private void saveNightModeState(boolean nightMode) {
        SharedPreferences.Editor editor = sharedpreferences.edit();
        editor.putBoolean(KEY_ISNIGHTMODE, nightMode);
        editor.apply();
    }

    private void checkNightModeActivated() {
        if(sharedpreferences.getBoolean(KEY_ISNIGHTMODE, false)) {
            aSwitch.setChecked(true);
            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
        }else{
            aSwitch.setChecked(false);
            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
        }
    }
}

The problem is, that the switch will change the mode to dark when I've started the app. But then, the app beginns to flicker and does not longer responds.

Can soneone please tell me, what I'm doing wrong?

Kind regards

Kai

Answer 1

I've found a solution for my problem.

private Switch day_night;

day_night=findViewById(R.id.day_night);
    day_night.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (isChecked) {
                getDelegate().setLocalNightMode(AppCompatDelegate.MODE_NIGHT_NO);
            }
            else {
                getDelegate().setLocalNightMode(AppCompatDelegate.MODE_NIGHT_YES);
            }
        }
    });