如何在关闭应用程序后保持单选按钮处于选中状态-android studio

我刚开始在Android Studio中编写代码，我刚刚了解了共享优先级。 我的老师给我布置了一个单选按钮组（RadioGroup），当你选中其中一个按钮时，关闭应用程序，再次打开，按钮将保持选中状态

就像您将

编辑文本

答案保存为

共享引用

，我需要将

单选按钮

保存为

共享引用

正如我所说，我对这一点还不熟悉，所以请简单回答：）

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--解决了，谢谢大家的回答！由于您的评论，我找到了解决方案！：D

以下是您如何在单选组上获得oncheckchange listener以在其中获得所选单选按钮的方法

注意！！！应为所有内部单选按钮提供ID

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和当应用程序启动时，您可以通过sharefPreference签入onCreate（），如果值已保存，则获取单选按钮并将其属性isSelected设置为true！我希望这足够简单

以下是您应该如何在单选通话组中获取oncheckchange listener以获取选中的单选按钮

注意！！！应为所有内部单选按钮提供ID

---

和当应用程序启动时，您可以通过sharefPreference签入onCreate（），如果值已保存，则获取单选按钮并将其属性isSelected设置为true！我希望这足够简单

首先，您要将listener设置为

RadioGroup

，如下所示：

RadioGroup radioGroup = (RadioGroup) findViewById(R.id.yourRadioGroup);        
    radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() 
    {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            // save id into your SharedPreferences
        }
    });

然后，您可以从共享首选项在onCreate（）中还原它，并调用

radioGroup.check（id）

因此，代码将如下所示：

SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
int checkedId = sharedPrefs.getInt("your key", 0);
radioGroup.check(checkedId);  

请注意，此代码已简化。您需要添加检查等。首先，您要将侦听器设置为
RadioGroup
，如下所示：

RadioGroup radioGroup = (RadioGroup) findViewById(R.id.yourRadioGroup);        
    radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() 
    {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            // save id into your SharedPreferences
        }
    });

public class MainActivity extends AppCompatActivity {
   // this will be key for the key value pair
   public static final String BUTTON_STATE = "Button_State";
   // this is name of shared preferences file, must be same whenever accessing
   // the key value pair.
   public static final String MyPREFERENCES = "MyPrefs" ;

   SharedPreferences sharedpreferences;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      // helper method to open up the file.
      sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
      // grab the last saved state here on each activity start
      Boolean lastButtonState = sharedpreferences.getBoolean(BUTTON_STATE, false)
      RadioButton rb = (RadioButton) findViewById(R.id.radio_button);
      // restore previous state
      rb.setChecked(lastButtonState);
      // set a listener
      rb.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            // call this to enable editing of the shared preferences file
            // in the event of a change
            SharedPreferences.Editor editor = sharedpreferences.edit();
            Boolean isChecked = rb.isChecked();
            // use this to add the new state
            editor.putBoolean(BUTTON_STATE, isChecked);
            // save
            editor.apply();
         }
      });
   }
}

然后，您可以从共享首选项在onCreate（）中还原它，并调用
radioGroup.check（id）

因此，代码将如下所示：

SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
int checkedId = sharedPrefs.getInt("your key", 0);
radioGroup.check(checkedId);  

请注意，此代码已简化。您需要添加支票等
试试这个

public class MainActivity extends AppCompatActivity {
   // this will be key for the key value pair
   public static final String BUTTON_STATE = "Button_State";
   // this is name of shared preferences file, must be same whenever accessing
   // the key value pair.
   public static final String MyPREFERENCES = "MyPrefs" ;

   SharedPreferences sharedpreferences;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      // helper method to open up the file.
      sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
      // grab the last saved state here on each activity start
      Boolean lastButtonState = sharedpreferences.getBoolean(BUTTON_STATE, false)
      RadioButton rb = (RadioButton) findViewById(R.id.radio_button);
      // restore previous state
      rb.setChecked(lastButtonState);
      // set a listener
      rb.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            // call this to enable editing of the shared preferences file
            // in the event of a change
            SharedPreferences.Editor editor = sharedpreferences.edit();
            Boolean isChecked = rb.isChecked();
            // use this to add the new state
            editor.putBoolean(BUTTON_STATE, isChecked);
            // save
            editor.apply();
         }
      });
   }
}

    RadioGroup radioGroup = findViewById(R.id.radio_gropup);
    final SharedPreferences preferences = getSharedPreferences("saved", 0);

    radioGroup.check(preferences.getInt("CheckedId", 0));

    radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            SharedPreferences.Editor editor = preferences.edit();
            editor.putInt("CheckedId", checkedId);
            editor.apply();
        }
    });

试试这个

    RadioGroup radioGroup = findViewById(R.id.radio_gropup);
    final SharedPreferences preferences = getSharedPreferences("saved", 0);

    radioGroup.check(preferences.getInt("CheckedId", 0));

    radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            SharedPreferences.Editor editor = preferences.edit();
            editor.putInt("CheckedId", checkedId);
            editor.apply();
        }
    });