Seekbar和setText顯示舊輸出

Question

我正在測試seek bar組件以獲得它的感覺，所以我將它添加到我的應用程序中。目標很簡單，當您拖動光標時，它將更改文本以指示進度。但由於某些原因，在屏幕上拖動它時，會留下光標圖像以及之前的結果，而不是僅僅用新的結果替換文本。這是代碼。非常基本的我會想。

public class Progressbar extends Activity implements OnSeekBarChangeListener 

{

SeekBar bar; // declare seekbar object variable 
// declare text label objects 
TextView textAction; 
/** Called when the activity is first created. */ 

@Override 
protected void onCreate(Bundle savedInstanceState) { 

    super.onCreate(savedInstanceState); 
    // load the layout 
    setContentView(R.layout.activity_progressbar);  
    bar = (SeekBar)findViewById(R.id.seekBar1); // make seekbar object 
    bar.setOnSeekBarChangeListener(this); // set seekbar listener. 
    // since we are using this class as the listener the class is "this" 


    // make text label for action 
    textAction = (TextView)findViewById(R.id.textViewAction); 

} 

@Override 
public void onProgressChanged(SeekBar seekBar, int progress, 
     boolean fromUser) { 
    // TODO Auto-generated method stub 

    // change action text label to changing 
    textAction.setText(textAction.getText() + "\n" +"SeekBar progress is at: "+ progress); 

} 

@Override 
public void onStartTrackingTouch(SeekBar seekBar) { 
    // TODO Auto-generated method stub 
    textAction.setText("starting to track touch"); 

} 

@Override 
public void onStopTrackingTouch(SeekBar seekBar) { 
    // TODO Auto-generated method stub 
    seekBar.setSecondaryProgress(seekBar.getProgress()); // set the shade of the previous value. 
    textAction.setText("ended tracking touch");  
} 

}

Answer 1

要附加新的進展之前的文本。你爲什麼不這樣做來檢查Seekbar。

textAction.setText(""+ progress);