通過RatingBar排序自己的適配器無法正常工作

我的應用程序包含所有安裝的應用程序（TextView和RatingBar）的ListView，並允許根據排名（在菜單中選擇）排序ListView的元素。這意味着，從菜單sort-> ranking-> descending f.e.中選擇選項後，ListView中包含已安裝的應用程序的名稱和排名，應按排名降序排列。問題是ListView沒有完全排序。它的作品，但沒有幾個元素，但..後滾動屏幕是好的。我能得到一些線索嗎？通過RatingBar排序自己的適配器無法正常工作

我注意到，當適配器進行排序時，只有可見的ListView項具有正確的排名，其他等於零。這是爲什麼？

的一段代碼：

public class MainActivity extends Activity { 
    private static final String PREFERENCES_NAME = "myPreferences3"; 
    public SharedPreferences pref; 
    public SharedPreferences.Editor prefEditor; 
    public ListView listView; 
    public List<ApplicationInfo> packages; 
    public PackageManager pm; 
    public App app_packages[]; 
    public AppAdapter adapter; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     pref=getSharedPreferences(PREFERENCES_NAME, MainActivity.MODE_PRIVATE); 
     prefEditor = pref.edit(); 
     setContentView(R.layout.main_activity); 

     pm=getPackageManager(); 
     packages = pm.getInstalledApplications(PackageManager.GET_META_DATA); 
     app_packages=new App[packages.size()]; 

     int i=0; 
     for (ApplicationInfo packageInfo : packages) 
     { 
      app_packages[i]=new App(pm.getApplicationLabel(packageInfo).toString()); 
      i++; 
     } 

     adapter = new AppAdapter(this, R.layout.app, app_packages); 
     listView=(ListView) findViewById(R.id.listView1); 
      listView.setAdapter(adapter); 
     } 


    //------------------------------------------------------------------------ 

    public class AppAdapter extends ArrayAdapter<App> 
    { 
     private static final String PREFERENCES_NAME = "myPreferences3"; 
     public SharedPreferences pref=getSharedPreferences(PREFERENCES_NAME, MainActivity.MODE_PRIVATE); 
     public SharedPreferences.Editor prefEditor=pref.edit(); 

     Context context; 
     App applications_array[]=null; 
     int layoutResourceId; 

     public AppAdapter(Context context, int layoutResourceId, App[] applications_array) 
     { 
      super(context, layoutResourceId, applications_array); 
      this.layoutResourceId=layoutResourceId; 
      this.context=context; 
      this.applications_array=applications_array; 
     } 

     @Override 
     public View getView(final int position, View convertView, ViewGroup parent) 
     {   
      View app=convertView; 
      AppHolder holder=null; 

      if(app==null) 
      { 
       LayoutInflater inflater=((Activity)context).getLayoutInflater();  
       app=inflater.inflate(layoutResourceId, parent, false); 

       holder=new AppHolder(); 
       holder.textView=(TextView)app.findViewById(R.id.appTitle); 
       holder.ratingBar=(RatingBar)app.findViewById(R.id.appScore); 
       app.setTag(holder); 
      } 
      else 
      { 
       holder=(AppHolder) app.getTag(); 
      } 



     holder.ratingBar.setOnRatingBarChangeListener(new RatingBar.OnRatingBarChangeListener(){ 

      @Override 
      public void onRatingChanged(RatingBar ratingBar, float rating, boolean fromUser) { 
       prefEditor.putFloat("rating"+applications_array[position].title, rating).commit(); 

          applications_array[position].rating=rating; 
          switch(pref.getString("sort", "")) 
          { 
           case "r_up": Sort_r_up(); 
            adapter.notifyDataSetChanged(); 
            listView.smoothScrollToPosition(adapter.getPosition(applications_array[position])); 
            break; 
           case "r_down": Sort_r_down(); 
            adapter.notifyDataSetChanged(); 
            listView.smoothScrollToPosition(adapter.getPosition(applications_array[position])); 
            break; 
          } 
       } 
       }); 
       holder.textView.setText(applications_array[position].title); 
       holder.ratingBar.setRating(pref.getFloat("rating"+applications_array[position].title, 0.0f)); 

      return app; 
     } 
    } 


    static class AppHolder 
    { 
     TextView textView; 
     RatingBar ratingBar; 
    } 

    public class App 
    { 
     public String title; 
     public float rating; 


     public App(){} 

     public App(String title) 
     { 
      this.title=title; 
      this.rating=0.0f; 
     } 

    } 
    //--------------------------------------------------------------- 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     getMenuInflater().inflate(R.layout.menu, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) 
    { 
     switch (item.getItemId()) 
     { 

       case R.id.r_up: 
       prefEditor.putString("sort", "r_up").commit(); 
      Sort_r_up(); 
       adapter.notifyDataSetChanged(); 
       return true; 

      case R.id.r_down: 
       prefEditor.putString("sort", "r_down").commit(); 
       Sort_r_down(); 
       adapter.notifyDataSetChanged(); 
       return true; 

      default: 
      return super.onOptionsItemSelected(item); 
     } 
    } 


    public void Sort_r_up() 
    { 
     adapter.sort(new Comparator<App>() 
     { 
      public int compare(App arg0, App arg1) { 
        if(arg0.rating>arg1.rating) 
         return 1; 
        else 
         return -1; 
       } 
     }); 
    } 

    public void Sort_r_down() 
    { 
     adapter.sort(new Comparator<App>() 
     { 
      public int compare(App arg0, App arg1) { 
        if(arg0.rating>=arg1.rating) 
         return -1; 
        else 
         return 1; 
      }  
     }); 

    } 
}

來源

2014-05-06 user3590445