在android中使用onTouch替換一個圖像

Question

我是一個初學者，使用圖形。現在我有一個圖像顯示在屏幕上隨機的地方。我想這樣做，如果圖像被觸摸，它應該被另一個圖像取代。我怎樣才能做到這一點？ 我目前正在使用一個類中的一個class.Thanks

public class MainActivity extends ActionBarActivity implements OnTouchListener{ 

MyGameGraphics myGraphics; 
TextView tvScore, tvPlayerScore; 




@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    tvScore = (TextView)findViewById(R.id.showScore); 
    tvPlayerScore = (TextView)findViewById(R.id.playerScore); 

    myGraphics = new GraphicsMain(this); 

    myGraphics.setOnTouchListener(this); 

    setContentView(myGraphics); 




    } 

@Override 
protected void onPause(){ 

    super.onPause(); 
    myGraphics.pause(); 


} 

@Override 
protected void onResume(){ 

    super.onResume(); 
    myGraphics.resume(); 
} 






@Override 
public boolean onTouch(View arg0, MotionEvent event) { 
    // TODO Auto-generated method stub 

    // How to change image using touch event here? 

    return false; 

} 





public class MyGameGraphics extends SurfaceView implements Runnable { 

    SurfaceHolder ourHolder; 
    Thread ourThread = null; 
    Boolean isRunning = false; 
    int[] images = new int[]{R.drawable.image1, R.drawable.image2}; 





    public MyGameGraphics(Context context) { 

     super(context); 
     ourHolder = getHolder(); 

    } 

     public void pause(){ 

      isRunning = false; 
      while(true){ 

       try { 


       ourThread.join(); 


      } catch (InterruptedException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 


      } 

      break; 
      } 
      ourThread = null; 

     } 

     public void resume(){ 

      isRunning = true; 
      ourThread = new Thread(this); 
      ourThread.start(); 

     } 


    @Override 
    public void run() { 



     while(isRunning){ 

      if(!ourHolder.getSurface().isValid()) 
      continue; 

      Canvas ourCanvas = ourHolder.lockCanvas(); 
      ourCanvas.drawRGB(0, 0, 0); 


      Random rn = new Random(); 
      int location = rn.nextInt(12); 

      for(int i = 0; i < 500; i++){ 

       try { 

      Random rn2 = new Random(); 
      int generateWidthLocation = rn2.nextInt(420); 
      int generateHeightLocation = rn2.nextInt(600); 


      Bitmap btmp = BitmapFactory.decodeResource(getResources(), images[location]); 
      ourCanvas.drawBitmap(btmp, generateWidthLocation, generateHeightLocation, null); 

       ourThread.sleep(3000); 




      } catch (InterruptedException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 
      break; 
     } 






      ourHolder.unlockCanvasAndPost(ourCanvas); 

     } 



      } 

} 

另一件事}

Answer 1

在OnTouch法，event參數有兩個功能：event.getX()和event.getY()。

然後，您只需要保留當前位置的generateWidthLocation和generateHeightLocation，並且您可以輕鬆確定圖像是否被觸摸（還需要保留圖像的高度/寬度）。

，您可能需要檢查，如果當用戶觸摸屏幕，移動手指或停止去觸摸它的OnTouch方法被稱爲：event.getAction()要麼是MotionEvent.ACTION_DOWN，MotionEvent.ACTION_MOVE或MotionEvent.ACTION_UP。

編輯：在您的MyGameGraphics添加以下屬性：

int[] images = new int[] { R.drawable.image1, R.drawable.image2 }; 
    int currentXImageLocation = 0; 
    int currentYImageLocation = 0; 
    int currentImageWidth = 0; 
    int currentImageHeight = 0; 

並經過ourCanvas.drawBitmap(btmp, generateWidthLocation, generateHeightLocation, null);地址：

currentXImageLocation = generateWidthLocation; 
    currentYImageLocation = generateHeightLocation; 
    currentImageHeight = btmp.getHeight(); 
    currentImageWidth = btmp.getWidth(); 

然後在你的MyGameGraphics類中添加這個功能：

public boolean isImageTouched(float x, float y) 
    { 
     boolean result = false; 

     if(x > currentXImageLocation && x < currentXImageLocation + currentImageWidth 
       && y > currentYImageLocation && y < currentYImageLocation + currentImageHeight) 
     { 
      result = true; 
     } 

     return result; 
    } 

而且最後在OnTouch方法中：

@Override 
public boolean onTouch(View arg0, MotionEvent event) { 

    if(event.getAction() == MotionEvent.ACTION_DOWN) 
    { 
     if(myGraphics.isImageTouched(event.getX(), event.getY())) 
     { 
      //Image was touched, do something... 
     } 
    } 

    return true; 
}