当我切换活动或关闭应用程序时，Android 中的共享首选项不会保存 [英] Shared preferences in Android doesn't save when i switch activity or close app

问题描述

我检查了类似的问题，注意到似乎有效.我无法弄清楚似乎是什么问题.每次应用重启或活动切换后，值都会变为 0.

I checked similar questionsions and noting seems to work. I can't figure out what seems to be the problem. Value goes to 0 after every app restart or activity switch.

//just parts of code from activity1
            SharedPreferences pref;
            SharedPreferences.Editor editor;
// On create....
            pref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
            editor = pref.edit();
            max=pref.getInt("mxtime", 0);

//If something>something...
            editor.putInt("mxtime", max);
            editor.commit();

在第一部分中，我在主活动中声明了 SharedPreferences.我将它保存在max"int 中，并且它在启动时始终为 0，因为如果空值为 0.在第二个活动中，我有一个按钮，点击它应该清空 SharedPreferences 中的值.

In the first part i declare SharedPreferences in main Activity. I save it in "max" int and its always 0 on startup since if empty value is 0. On second activity I have a button, where on click it should empty the value from SharedPreferences.

活动 2:

public class settings extends AppCompatActivity {
private Button myButton;
private Button myButton2;
private Button myButton3;
//sharedPrefs
SharedPreferences pref;
SharedPreferences.Editor editor;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_settings);

    pref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
    editor = pref.edit();
    myButton = (Button) findViewById(R.id.button3);
    myButton2 = (Button) findViewById(R.id.button4);
    myButton3 = (Button) findViewById(R.id.button5);

    myButton.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v) {
            Intent i = new Intent(getApplicationContext(),MainActivity.class);
            startActivity(i);


        }
    });
    myButton2.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v) {
            //sharedPrefs
            editor.remove("mxtime");
            editor.commit();


        }
    });
}

}

推荐答案

尝试像这样使用 SharedPreferences:

Try to use SharedPreferences like this:

 SharedPreferences preferences = getApplicationContext().getSharedPreferences("loginPref", MODE_PRIVATE);
 SharedPreferences.Editor editor = preferences.edit();

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