gridview setNotifiedDataSetChanged（）沒有順利更新gridview？

Question

我嘗試平穩地更新gridview背景顏色，但不起作用。 當我scrool gridview當時它得到改變; PLZ指導我如何做到這一點，下面是我的代碼，謝謝你。

TableGridViewAdapter gridadapter; 
GridView gridview; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

      textViewUname = (TextView) this.findViewById(R.id.userName); 
      textViewUname.setText("Welcome , " + HomeActivity.name); 

      gridview = (GridView) findViewById(R.id.gridview); 
      gridadapter=new TableGridViewAdapter(this); 
      gridview.setAdapter(gridadapter); 
      //adapter.notifyDataSetChanged();    

      UpdateGridview updateGridview=new UpdateGridview(); 
      updateGridview.execute(TableActivity.this); 



      // code for onClick gridview items , It take to that Activity 
      gridview.setOnItemClickListener(new OnItemClickListener() { 

       @Override 
       public void onItemClick(AdapterView<?> parent, View v, 
         int position, long id) { 
        ConText.currentPos = position; 
        Intent i = new Intent(TableActivity.this, 
          OrderListActivity.class); 
        i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK 
          | Intent.FLAG_ACTIVITY_CLEAR_TOP); 
        startActivity(i); 
        finish(); 

       } 

      }); 
     } 
    } 

} 

這裏我tryed到在刷新每隔20秒

private class UpdateGridview extends AsyncTask<Context, Integer, String> 
     {  
     @Override 
     protected String doInBackground(Context... params) 
     { 

       int i = 0; 
       while(i <10) 
       { 
         try{ 

           gridadapter.notifyDataSetChanged(); 
           // gridadapter.refreshItems(gridadapter); 
           gridview.invalidate(); 

           //TableGridViewAdapter.refreshItems(gridadapter); 
           Thread.sleep(20000); 
           System.out.println("i called notifyDataSetChanged()======================="); 
           i++; 
         } catch(Exception e){ 
           Log.i("makemachine", e.getMessage()); 
         } 
       } 
       return "COMPLETE!"; 
     } 

// -- gets called just before thread begins 
     @Override 
     protected void onPreExecute() 
     { 
       Log.i("makemachine", "onPreExecute()"); 
       super.onPreExecute(); 

     } 


     @Override 
     protected void onProgressUpdate(Integer... values) 
     { 
       super.onProgressUpdate(values); 

     } 

     // -- called if the cancel button is pressed 
     @Override 
     protected void onCancelled() 
     { 
       super.onCancelled(); 
       Log.i("makemachine", "onCancelled()"); 

     } 

     // -- called as soon as doInBackground method completes 
     // -- notice that the third param gets passed to this method 
     @Override 
     protected void onPostExecute(String result) 
     { 
       super.onPostExecute(result); 
       Log.i("makemachine", "onPostExecute(): " + result); 

     } 

}

}

Answer 1

視圖試試這樣：

private final Handler handler = new Handler() { 
     public void handleMessage(Message msg) { 
      if(msg.arg1 == 1){ 
       gridadapter.notifyDataSetChanged(); 
      } 
     } 
    }; 



private class UpdateGridview extends AsyncTask<Context, Integer, String> 
     {  
     @Override 
     protected String doInBackground(Context... params) 
     { 

       int i = 0; 
       while(i <10) 
       { 
         try{ 

           // gridadapter.notifyDataSetChanged(); 
           // gridadapter.refreshItems(gridadapter); 
           //gridview.invalidate(); 
           Message msg = handler.obtainMessage(); 
           msg.arg1 = 1; 
           handler.sendMessage(msg); 
           //TableGridViewAdapter.refreshItems(gridadapter); 
           Thread.sleep(20000); 
           System.out.println("i called notifyDataSetChanged()======================="); 
           i++; 
         } catch(Exception e){ 
           Log.i("makemachine", e.getMessage()); 
         } 
       } 
       return "COMPLETE!"; 
     } 

// -- gets called just before thread begins 
     @Override 
     protected void onPreExecute() 
     { 
       Log.i("makemachine", "onPreExecute()"); 
       super.onPreExecute(); 

     } 


     @Override 
     protected void onProgressUpdate(Integer... values) 
     { 
       super.onProgressUpdate(values); 

     } 

     // -- called if the cancel button is pressed 
     @Override 
     protected void onCancelled() 
     { 
       super.onCancelled(); 
       Log.i("makemachine", "onCancelled()"); 

     } 

     // -- called as soon as doInBackground method completes 
     // -- notice that the third param gets passed to this method 
     @Override 
     protected void onPostExecute(String result) 
     { 
       super.onPostExecute(result); 
       Log.i("makemachine", "onPostExecute(): " + result); 

     } 
} 

}