这是我在settings.java类中的代码。我已经实现了我的设置类，就像这样。我想让黑暗的主题，杀死应用程序后，它必须存在于那里，以及切换必须是真实的。
现在我已经实现了使它变暗。但是当我杀死应用程序，再次出现时，它会消失。切换也会关闭。

public class settings extends AppCompatActivity {
    SwitchCompat switchCompat;
    ImageView backbtn;
    Button button;    
    @SuppressLint("WrongViewCast")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_settings);
        if (AppCompatDelegate.getDefaultNightMode() == AppCompatDelegate.MODE_NIGHT_YES) {
            setTheme(R.style.Base_ThemeOverlay_AppCompat_Dark);
        } else {
            setTheme(R.style.Base_Theme_MaterialComponents_Light);
        }
            backbtn = findViewById(R.id.goingback);
        LoadingDialod loadingDialod = new LoadingDialod(settings.this);

        backbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(getApplicationContext(), MainActivity.class);
                startActivity(intent);
            }
        });
        switchCompat.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
                if (isChecked) {
                    loadingDialod.startloadinganimation();

                    new Handler().postDelayed(new Runnable() {
                        @Override
                        public void run() {                             AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
                            Intent intent = new Intent(getApplicationContext(), settings.class);
                            startActivity(intent);
                        }
                    }, 800);

                } else {
                    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);

                }
            }
        });
    }
}

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