如何在我的Android应用中保护夜间模式的状态？

问题描述

我的应用程序中有一个settings-activity，用户可以在其中选择亮模式，暗模式，并通过三个单选按钮跟随系统。但是，当应用程序重新启动时，无论单选按钮上选择了什么，都将始终遵循该系统。我用SharedPreferences尝试过，但是没有用。我该如何解决？

java类：

package com.example.formelrechner;

import...

public class Einstellungen extends AppCompatActivity {

    RadioGroup radioGroup;
    RadioButton radioButton,radioButton2,radioButton3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        if (AppCompatDelegate.getDefaultNightMode()==AppCompatDelegate.MO DE_NIGHT_YES) {
            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
        }

        if (AppCompatDelegate.getDefaultNightMode()==AppCompatDelegate.MODE_NIGHT_NO) {
            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
        }

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_einstellungen);


        radioGroup = findViewById(R.id.radiogroup);
        radioButton = findViewById(R.id.radioButton);
        radioButton2 = findViewById(R.id.radioButton2);
        radioButton3 = findViewById(R.id.radioButton3);

        radioButton.setChecked(Update("SaveStateOne"));
        radioButton2.setChecked(Update("SaveStateTwo"));
        radioButton3.setChecked(Update("SaveStateThree"));



        radioButton.setonCheckedchangelistener(new CompoundButton.OnCheckedchangelistener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView,boolean one_isChecked) {
                SaveintosharedPrefs("SaveStateOne",one_isChecked);
                if (one_isChecked) {
                    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);

                }
            }
        });

        radioButton2.setonCheckedchangelistener(new CompoundButton.OnCheckedchangelistener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView,boolean two_isChecked) {
                SaveintosharedPrefs("SaveStateTwo",two_isChecked);
                if (two_isChecked) {
                    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
                }
            }
        });

        radioButton3.setonCheckedchangelistener(new CompoundButton.OnCheckedchangelistener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView,boolean three_isChecked) {
                SaveintosharedPrefs("SaveStateThree",three_isChecked);
                if (three_isChecked) {
                    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYstem);
                }
            }
        });

    }

    private void SaveintosharedPrefs(String key,boolean value) {

        SharedPreferences sp = getSharedPreferences("SaveState",MODE_PRIVATE);
        final SharedPreferences.Editor editor = sp.edit();

        editor.putBoolean(key,value);
        editor.apply();
    }

    private boolean Update(String key) {

        SharedPreferences sp = getSharedPreferences("SaveState",MODE_PRIVATE);
        return sp.getBoolean(key,false);
    }

}

解决方法

我为Kotlin的应用程序做了同样的事情。但是您可以将其转换为Java，几乎是一样的。

您需要为“共享首选项”创建一个新类：

class SettingsSaveData(context:Context) {

private var sharedPreferences: SharedPreferences =context.getSharedPreferences("file",Context.MODE_PRIVATE)

fun setDarkMode(state: Boolean){
    val editor = sharedPreferences.edit()
    editor.putBoolean("Dark",state)
    editor.apply()
}

fun loadDarkMode(): Boolean? {
    val state = sharedPreferences.getBoolean("Dark",false)
    return (state)
}

}

在“设置活动”中，您需要输入以下内容：

class SettingsActivity : AppCompatActivity() {   
   private lateinit var settingSaveData: SettingsSaveData

override fun onCreate(savedInstanceState: Bundle?) {
    settingSaveData = SettingsSaveData(this)  // make sure to setTheme here
    if (settingSaveData.loadDarkMode() == true){  // before onCreate method
        setTheme(R.style.DarkTheme)
    }else{
        setTheme(R.style.AppTheme)
    }

    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_settings)

    if(settingSaveData.loadDarkMode() == true){
        switch_theme.isChecked = true            // switch_theme is my Switch
    }

    switch_theme.setOnCheckedChangeListener { _,isChecked ->
        if (isChecked) {
            settingSaveData.setDarkMode(true)
            restartApplication()
        }else{
            settingSaveData.setDarkMode(false)
            restartApplication()
    }  
private fun restartApplication(){
    val i = Intent(applicationContext,SettingsActivity::class.java)
    startActivity(i)
    finish()
}

在所有活动中，您只需要声明：

private lateinit var settingsSaveData:SettingsSaveData

，然后在onCreate方法中设置主题：

 settingsSaveData = SettingsSaveData(this)
    if (settingsSaveData.loadDarkMode() == true){
        setTheme(R.style.DarkTheme)
    }else{
        setTheme(R.style.AppTheme)
    }
    super.onCreate(savedInstanceState)

我希望这会对您有所帮助！