Question

我正在开发一个在DarkMode主题中使用的应用程序，该应用程序将Switch设置为打开和关闭darkMode，然后将其保存在布尔型小节中，这意味着darkMode是真还是假（boolean isDarkMode =false;）< / p>

它运作良好，我使用SharedPreferences保存此true或false值以在其他活动中使用它。它工作，但是... 当我关闭应用程序并再次运行应用程序时，SharedPreferences的值未保存，并返回到boolian的第一个值（谢谢你）

SettingActivity.java（设置布尔型为true或false）

package com.kurdfoxx.nightmodewithsharedprefrense;

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

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.Switch;
import android.widget.Toast;

public class SettingActivity extends AppCompatActivity {
    Switch mySwitch;
    boolean isDarkMode =false;
    private static final String DARKMODE = "login";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        myboolian();
        if (AppCompatDelegate.getDefaultNightMode() == AppCompatDelegate.MODE_NIGHT_YES) {
            setTheme(R.style.darkTheme);
            isDarkMode =true;

        } else {
            setTheme(R.style.AppTheme);
            isDarkMode =false;


        }
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_setting);
        Toast.makeText(this, ""+ isDarkMode, Toast.LENGTH_SHORT).show();
        mySwitch = findViewById(R.id.switch1);
        if (AppCompatDelegate.getDefaultNightMode() == AppCompatDelegate.MODE_NIGHT_YES) {
            mySwitch.setChecked(true);
        }
        mySwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isChecked) {
                    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
                    isDarkMode =true;
                    restartApp();
                } else {
                    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
                    isDarkMode =false;

                    restartApp();

                }
            }
        });


        Button buttonGoMain=findViewById(R.id.btn_go_MainAct);
        buttonGoMain.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(SettingActivity.this,MainActivity.class));

            }
        });


    }

    public void restartApp() {
        Intent intentRestartApp = new Intent(getApplicationContext(), SettingActivity.class);
        startActivity(intentRestartApp);
        finish();

    }
    public void myboolian(){
           isDarkMode =!isDarkMode;  //change isDarkMode from false to true by this
        SharedPreferences sharedPreferences =getSharedPreferences(DARKMODE,MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putBoolean("ISDARKMODE", isDarkMode);
        editor.apply();


    }


}

和MainActivity.java

package com.kurdfoxx.nightmodewithsharedprefrense;

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

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {
    private static final String DARKMODE = "login";
    boolean isDarkMode = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        getData();
        if (isDarkMode){

            if (AppCompatDelegate.getDefaultNightMode() == AppCompatDelegate.MODE_NIGHT_YES) {
                setTheme(R.style.darkTheme);
                isDarkMode =true;
            } else {
                setTheme(R.style.AppTheme);
                isDarkMode =false;

            }
        }
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button=findViewById(R.id.button_go_to_setting_activity);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MainActivity.this,SettingActivity.class));
            }
        });

    }
    private void getData() {

        SharedPreferences sharedPreferences = getSharedPreferences(DARKMODE, MODE_PRIVATE);
        isDarkMode = sharedPreferences.getBoolean("ISDARKMODE", false);

    }

}

Answer 1

在checkedChangedListener中，分别将darkMode设置为true和false。

在您的myboolian方法中，您是唯一写入变量的地方。

仅从您的onCreate中调用此方法，仅，在其他任何地方都无法调用。除此之外，此方法始终设置darkMode = !darkMode，交换值。

您必须在onCheckedChanged中调用myboolian并删除darkMode = !darkMode，否则您将始终重置为之前的值。

Answer 2

感谢@Grisgram的帮助我通过一些更改和对

的坚持认为减轻了这个问题

settingActivity.java

package com.kurdfoxx.nightmodewithsharedprefrense;

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

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.Switch;
import android.widget.Toast;

public class SettingActivity extends AppCompatActivity {
   public static Switch mySwitch;
    boolean isDarkMode =false;
    private static final String DARKMODE = "dark";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        if (AppCompatDelegate.getDefaultNightMode() == AppCompatDelegate.MODE_NIGHT_YES) {
            setTheme(R.style.darkTheme);
            isDarkMode=true;

        } else {
            setTheme(R.style.AppTheme);
            isDarkMode=false;


        }
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_setting);
        Toast.makeText(this, ""+ isDarkMode, Toast.LENGTH_SHORT).show();
        mySwitch = findViewById(R.id.switch1);
        if (AppCompatDelegate.getDefaultNightMode() == AppCompatDelegate.MODE_NIGHT_YES) {
            mySwitch.setChecked(true);
        }
        mySwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isChecked) {
                    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
                    isDarkMode=true;
                    myboolian();


                    restartApp();
                } else {
                    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
                    isDarkMode=false;
                    myboolian();

                    restartApp();

                }
            }
        });
        myboolian();

        Button buttonGoMain=findViewById(R.id.btn_go_MainAct);
        buttonGoMain.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(SettingActivity.this,MainActivity.class));

            }
        });


    }

    public void restartApp() {
        Intent intentRestartApp = new Intent(getApplicationContext(), SettingActivity.class);
        startActivity(intentRestartApp);
        finish();

    }
    public void myboolian(){
     // isDarkMode =!isDarkMode;  //change isDarkMode from false to true by this
        SharedPreferences sharedPreferences =getSharedPreferences(DARKMODE,MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putBoolean("ISDARKMODE", isDarkMode);
        editor.apply();


    }


}

和主要活动

package com.kurdfoxx.nightmodewithsharedprefrense;

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

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private static final String DARKMODE = "dark";
    boolean isDarkMode ;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        getData();
        Toast.makeText(this, "is datk ?"+isDarkMode, Toast.LENGTH_SHORT).show();

        if (isDarkMode){
                setTheme(R.style.darkTheme);
        }else {setTheme(R.style.AppTheme);}
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button=findViewById(R.id.button_go_to_setting_activity);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MainActivity.this,SettingActivity.class));
            }
        });

    }
    private void getData() {

        SharedPreferences sharedPreferences = getSharedPreferences(DARKMODE, MODE_PRIVATE);
        isDarkMode = sharedPreferences.getBoolean("ISDARKMODE", false);



    }




}

重新启动应用程序时，SharedPreferences不保存布尔值

2 个答案: