重新启动应用程序时，SharedPreferences 不保存布尔值

Question

我正在开发一个在 DarkMode 主题中使用的应用程序，我将 Switch 设置为打开和关闭 darkMode，并将其保存在布尔值中，这意味着 darkMode 为真或假（boolean isDarkMode =false; )

它运行良好，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...... 当我再次关闭应用程序和运行应用程序时，SharedPreferences 的值不会被保存，它会返回到布尔值的第一个值（谢谢你）

SettingActivity.java（设置布尔值真或假）

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

在您的 checkedChangedListener 中，您将 darkMode 分别设置为 true 和 false。

并且在您的 myboolian 方法中是您写入变量的唯一地方。

此方法仅从您的onCreate 调用，其他地方均未调用。除此之外，此方法总是设置 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解决了这个问题，并坚持

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 activity

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

SharedPreferences not save boolean value when restart app

java

android-studio

sharedpreferences