Question

我正在编写一个Android应用程序，我在使用SharedPreferences保存int变量时遇到了困难。我已经检查了我的代码一千次，但我还没有找到问题部分。我有两个活动。在Activity1中，我有一个通向第二个按钮的按钮。在Activity2中，我有一个按钮，添加50＆＃34;点＆＃34;到我的变量。我将此变量保存在onPause和onStop方法中。之后我回到Activity1，我再次获得0分。

活动1：

private static final String HINT = "Hint";
private static final String VALUE = "VALUE";
int hints;

      @Override
      protected void onCreate(Bundle savedInstanceState) {
      this.requestWindowFeature(Window.FEATURE_NO_TITLE);
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_mainketto);      this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,  WindowManager.LayoutParams.FLAG_FULLSCREEN);
    this.setContentView(R.layout.activity_mainketto);

    SharedPreferences sphint = getApplicationContext().getSharedPreferences(HINT, MODE_PRIVATE);
    hints = sphint.getInt(VALUE, 0);

    android.support.v7.app.ActionBar actionbar = getSupportActionBar();
    actionbar.hide();

    Toast.makeText(MainActivity.this, "" + hints,
            Toast.LENGTH_LONG).show();

   Button points = (Button)findViewById(R.id.button3);


   points.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Intent i = new Intent(MainActivity.this,PointsActivity.class);
            startActivity(i);
        }
    });
 }


  @Override
  protected void onPause() {


         SharedPreferences sphint =     getApplicationContext().getSharedPreferences(HINT, MODE_PRIVATE);
    SharedPreferences.Editor et2 = sphint.edit();
    et2.putInt(VALUE, hints);
    et2.commit();

    super.onPause();
}

@Override
protected void onStop() {

SharedPreferences sphint = getApplicationContext().getSharedPreferences(HINT, MODE_PRIVATE);
    SharedPreferences.Editor et2 = sphint.edit();
    et2.putInt(VALUE, hints);
    et2.commit();
    super.onStop();
}

活性2：

  private static final String HINT = "Hint";
  private static final String VALUE = "VALUE";
  int hints;


   @Override
    protected void onCreate(Bundle savedInstanceState) {
    this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_pontpiac);
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    this.setContentView(R.layout.activity_pontpiac);

    android.support.v7.app.ActionBar actionbar = getSupportActionBar();
    actionbar.hide();


    SharedPreferences sphint = getApplicationContext().getSharedPreferences(HINT, MODE_PRIVATE);
    hints = sphint.getInt(VALUE, 0);


    Toast.makeText(Pontpiac.this, ""+hints,
            Toast.LENGTH_LONG).show();

   Button btn = (Button)findViewById(R.id.tesztfos);

    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            hints = hints + 50;
            Toast.makeText(Pontpiac.this, ""+hints,
                    Toast.LENGTH_LONG).show();
        }
    });


  @Override
  protected void onPause() {

    SharedPreferences sphint = getApplicationContext().getSharedPreferences(HINT, MODE_PRIVATE);
    SharedPreferences.Editor et2 = sphint.edit();
    et2.putInt(VALUE, hints);
    et2.commit();

    super.onPause();
}

   @Override
   protected void onStop() {
 SharedPreferences sphint = getApplicationContext().getSharedPreferences(HINT, MODE_PRIVATE);
    SharedPreferences.Editor et2 = sphint.edit();
    et2.putInt(VALUE, hints);
    et2.commit();

    super.onStop();
}

如果有人知道如何让它发挥作用，请回复！

Answer 1

您需要在第一个活动的onResume中再次获得偏好

Answer 2

Activity.onCreate()通常只在首次创建Activity时调用一次。它就像一个虚拟构造函数。当您从Activity2导航回Activity1时，不会再次调用Activity1的onCreate()。正如@tyczj在他的回答中所说，你需要覆盖onResume()并再次获得该值。例如：

@Override
protected void onResume() {
    SharedPreferences sphint = getApplicationContext().getSharedPreferences(HINT, MODE_PRIVATE);
    hints = sphint.getInt(VALUE, 0);
}

顺便说一句，我不确定你为什么要使用getApplicationContext().getSharedPreferences(...)。您的Activity是Context。您只需致电getSharedPreferences(...)即可。

Answer 3

您可以使用我的库：https://github.com/mkiisoft/KeySaver是一个“超级”SharedPreference，它允许您像这样保存int，String和boolean：

KeySaver.saveShare(this, "your-key", 1); //or any int

获取值：

KeySaver.getIntSavedShare(this, "your-key");

SharedPreferences不使用int值

3 个答案: