java - 共享首选项不保存 Android 应用程序的确切实例状态

Question

我正在使用 Java 创建一个简单的点击计数器 Android 应用程序。我是 Java 新手。我试图在应用程序退出时保存计数，无论是否按下后退按钮、应用程序关闭或崩溃等。这是迄今为止我的代码:

public class wazeefa extends Activity  {

//Count Button  
TextView txtCount;
Button btnCount;
int count; 
Button wmute;
Button wreset;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.wazeefa);

    //SAVE COUNT
    SharedPreferences app_preferences = 
       PreferenceManager.getDefaultSharedPreferences(this);

    count = app_preferences.getInt("count", 0);

    txtCount = (TextView)findViewById(R.id.wcount);
    txtCount.setText("This app has been started " + count + " times.");

    SharedPreferences.Editor editor = app_preferences.edit();
    editor.putInt("count", ++count);
    editor.commit();

    //Button SOUND AND COUNT
    final MediaPlayer mpButtonClick = MediaPlayer.create(this, R.raw.bubble);

    txtCount = (TextView)findViewById(R.id.wcount); 
    txtCount.setText(String.valueOf(count));
    btnCount = (Button)findViewById(R.id.wclick);   

    btnCount.setOnClickListener(new OnClickListener() {
        public void onClick(View V) {
        final ImageView image = (ImageView) findViewById(R.id.imageview);
           count++; 
           if (count > 50) count = 0; image.setImageResource(R.drawable.duroodimage);
           if (count > 0) image.setImageResource(R.drawable.duroodimage);
           if (count > 9) image.setImageResource(R.drawable.zikrimage); 
           if (count > 39) image.setImageResource(R.drawable.duroodimage);
           txtCount.setText(String.valueOf(count));
           mpButtonClick.start(); 

    //RESET Button
    wreset = (Button)findViewById(R.id.wreset);       
    wreset.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            count = 0; 
            image.setImageResource(R.drawable.duroodimage);;
               txtCount.setText("0");


    }

我的应用程序遇到两个问题。

首先，当应用程序关闭然后再次打开时，计数不会保存到原来的状态。例如，如果计数为“20”并且我点击后退按钮，则返回到同一页面，计数将显示为“3”。 - 有趣的是，每次我尝试上述操作并在点击后退按钮后返回应用程序时，计数都会增加 1 次。

第二个问题是，当我返回应用程序并且计数显示为“5”时，“重置”按钮不再起作用 - 它什么也不做。但是当我继续计数然后点击重置按钮时，它会再次将计数更改为零。

请问有人可以协助解决上述两个问题吗？

建议后的新代码:

public class wazeefa extends Activity  {

//Count Button  
TextView txtCount;
Button btnCount;
Button wmute;
Button wreset;
public static int count=0;
SharedPreferences app_preferences;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.wazeefa);

    //SAVE COUNT
    SharedPreferences app_preferences = 
            PreferenceManager.getDefaultSharedPreferences(this);

    count = app_preferences.getInt("count", 0);

    txtCount = (TextView)findViewById(R.id.wcount);
    txtCount.setText("This app has been started " + count + " times.");}

protected void onPause() {
     super.onPause();

    // save count value here
   SharedPreferences.Editor editor = app_preferences.edit();
   editor.putInt("count", count);
   editor.commit();

    //SOUND and COUNT
    final MediaPlayer mpButtonClick = MediaPlayer.create(this, R.raw.bubble);

    txtCount = (TextView)findViewById(R.id.wcount); 
    txtCount.setText(String.valueOf(count));
    btnCount = (Button)findViewById(R.id.wclick);   

    btnCount.setOnClickListener(new OnClickListener() {
        public void onClick(View V) {
        final ImageView image = (ImageView) findViewById(R.id.imageview);
           count++; 
           if (count > 50) count = 0; image.setImageResource(R.drawable.duroodimage);
           if (count > 0) image.setImageResource(R.drawable.duroodimage);
           if (count > 9) image.setImageResource(R.drawable.zikrimage); 
           if (count > 39) image.setImageResource(R.drawable.duroodimage);
           txtCount.setText(String.valueOf(count));
           mpButtonClick.start(); 

    //RESET Button
    wreset = (Button)findViewById(R.id.wreset);       
    wreset.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            count = 0; 
            image.setImageResource(R.drawable.duroodimage);;
               txtCount.setText("0");


    }

我的代码的最后部分:

 protected void onPause() {
         super.onPause();

    // save count value here

      SharedPreferences.Editor editor = app_preferences.edit();
      editor.putInt("count", count);
      editor.commit();


         };
     });
      }});
  };}

Answer 1

在类级别将计数声明为静态:

public static int count=0;
SharedPreferences app_preferences ;

并使用onPause将计数值保存在SharedPreferences中:

 protected void onPause() {
     super.onPause();

    // save count value here
   SharedPreferences.Editor editor = app_preferences.edit();
   editor.putInt("count", count);
   editor.commit();
 }