Android將ImageView拖放到另一個ImageView或佈局中

Question

我想在另一個ImageView或Layout中完成一個簡單的ImageView拖放操作。下面是我想要做的

我知道做到這一點的唯一方法照片通過具有2點線性佈局，一個「FROM」和「TO」，並分配到第二佈局的背景灰色的信件的圖像。

這裏是我的代碼

public class MainActivity extends Activity implements OnTouchListener, 
    OnDragListener { 

private static final String LOGCAT = null; 

/* 
* Here are the links I've been using 
* http://www.techrepublic.com/blog/software-engineer/try-androids-useful-drag-and-drop-api/ 
* http://codingjunkie.net/android-drag-and-drop-part-2/ 
* http://javapapers.com/android/android-drag-and-drop/ 
*/ 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    findViewById(R.id.letter_a).setOnTouchListener(this);  // My yellow letter a image 
    findViewById(R.id.top_container).setOnDragListener(this); // My 1st linear layout 
    findViewById(R.id.bottom_container).setOnDragListener(this); // My 2nd linear layout with "grayed a" image 
} 

@Override 
public boolean onTouch(View view, MotionEvent motionEvent) { 
    if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) { 
     DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view); 
     view.startDrag(null, shadowBuilder, view, 0); 
     view.setVisibility(View.INVISIBLE); 
     return true; 
    } else { 
     return false; 
    } 
} 

@Override 
    public boolean onDrag(View layoutview, DragEvent dragevent) { 

     int action = dragevent.getAction(); 
     View view = (View) dragevent.getLocalState(); 

     switch (action) { 
     case DragEvent.ACTION_DRAG_STARTED: 
     break; 
     case DragEvent.ACTION_DRAG_ENTERED: 
     break; 
     case DragEvent.ACTION_DRAG_EXITED: 
     break; 
     case DragEvent.ACTION_DROP: 
      ViewGroup owner = (ViewGroup) view.getParent(); 
      owner.removeView(view); 
      LinearLayout container = (LinearLayout) layoutview; 
      container.addView(view); 
      view.setVisibility(View.VISIBLE); 
      break; 
     case DragEvent.ACTION_DRAG_ENDED: 
      Log.d(LOGCAT, "Drag ended"); 
      if (dropEventNotHandled(dragevent)){ 
       view.setVisibility(View.VISIBLE); 
      } 
      break; 
     default: 
      break; 
     } 
     return true; 
    } 

private boolean dropEventNotHandled(DragEvent dragEvent) { 
    return !dragEvent.getResult(); 
} 
} 

我已經設法獲得onTouch和ondrag當工作和移動時檢測，但我想將其鎖定到位，因此它不能拖回到它原來的地方。

非常感謝！

Answer 1

如果它應該留在bottom_container中，只要註銷聽衆，如果它已經被放在那裏，例如，像這樣：

case DragEvent.ACTION_DROP: 
      ViewGroup owner = (ViewGroup) view.getParent(); 
      owner.removeView(view); 
      LinearLayout container = (LinearLayout) layoutview; 
      container.addView(view); 
      view.setVisibility(View.VISIBLE); 
      if(container.getId()==R.id.bottom_container){ 
       view.setOnTouchListener(null); 
       owner.setOnDragListener(null); 
      } 
    break;