Android拖放问题不显示

本文介绍了Android拖放问题不显示的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我正在努力拖放应用程序，一切都正常，但我看到一个问题。我有3个ImageViews，其中两个是可拖动对象，另一个是放置目标。每次将物体放在任何位置，而不是放下目标，它完全消失！

以下是我使用的代码：

ImageView iv1，iv2 ，iv3; @Override protected void onCreate（Bundle savedInstanceState）{ super.onCreate（savedInstanceState）; setContentView（R.layout.activity_main）; initControls（）; } private void initControls（）{ // TODO自动生成的方法存根 iv1 =（ImageView）findViewById R.id.imageView1）; iv2 =（ImageView）findViewById（R.id.imageView2）; iv1.setTag（a）; iv2.setTag（b）; iv3 =（ImageView）findViewById（R.id.imageView3）; iv1.setOnTouchListener（new MyTouchListener（））; iv2.setOnTouchListener（new MyTouchListener（））; iv3.setOnDragListener（new MyDragListener（））; } 私有最终类MyTouchListener实现OnTouchListener { public boolean onTouch（View view，MotionEvent motionEvent）{ if（motionEvent.getAction（） == MotionEvent.ACTION_DOWN）{ ClipData data = ClipData.newPlainText（，）; DragShadowBuilder shadowBuilder = new View.DragShadowBuilder（view）; view.startDrag（data，shadowBuilder，view，0）; view.setVisibility（View.INVISIBLE）; 返回true; } else { return false; } } } class MyDragListener实现OnDragListener { // Drawable enterShape = getResources（）。getDrawable（R.drawable.shape_droptarget）; // Drawable normalShape = getResources（）。getDrawable（R.drawable.shape）; @Override public boolean onDrag（View v，DragEvent event）{ switch（event.getAction（））{ case DragEvent.ACTION_DRAG_LOCATION： if（v！= iv3） v.setVisibility（View.VISIBLE）; break; case DragEvent.ACTION_DRAG_STARTED： // do nothing break; case DragEvent.ACTION_DRAG_ENTERED： break; case DragEvent.ACTION_DRAG_EXITED： break; case DragEvent.ACTION_DROP： //丢弃，重新分配视图到ViewGroup //处理通过放置视图删除的拖动视图 View view =（View ）event.getLocalState（）; Drawable dropshadow = getResources（）。getDrawable（R.drawable.dropshadow）; //查看拖动的项目被删除 ImageView dropTarget =（ImageView）v; //查看被拖放 ImageView dropped =（ImageView）view; / * //如果一个项目已经被删除，那将会有一个标签 Object tag = dropTarget.getTag（）; //如果这里已经有一个项目，将其设置为在原始位置可见 if（tag！= null） { //标签是这里的视图ID已经丢失 int existingID =（Integer）标签; //将原始视图再次设置为 findViewById（existingID）.setVisibility（View.VISIBLE）; } //将目标视图中的标签设置为要删除的视图的ID dropTarget.setTag（dropped.getId（））; * / String temp =a; if（temp.equals（view.getTag（）））{ //dropped.setBackground(dropshadow）; dropTarget.setBackground（dropshadow）; Log.d（temp，Correct Image）; } else { Log.d（b，Wrong Image）; view.setVisibility（View.VISIBLE）; } break; case DragEvent.ACTION_DRAG_ENDED： 默认值： break; } 返回true; } }

我在这里缺少什么？任何帮助是真正的赞赏。谢谢。

解决方案

最后我自己解决了这个问题。我添加了这个方法：

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

并添加：

case DragEvent.ACTION_DRAG_ENDED： if（dropEventNotHandled（event）） view.setVisibility（View.VISIBLE）; break;

I'm working on a drag and drop application, everything is working fine but I saw an issue. I have 3 ImageViews, two of them are draggable objects and the other one is the drop target. Every time I drop the object in any location other than the drop target, it's totally disappearing!

Below is the code I used:

ImageView iv1, iv2, iv3; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initControls(); } private void initControls() { // TODO Auto-generated method stub iv1 = (ImageView) findViewById (R.id.imageView1); iv2 = (ImageView) findViewById (R.id.imageView2); iv1.setTag("a"); iv2.setTag("b"); iv3 = (ImageView) findViewById (R.id.imageView3); iv1.setOnTouchListener(new MyTouchListener()); iv2.setOnTouchListener(new MyTouchListener()); iv3.setOnDragListener(new MyDragListener()); } private final class MyTouchListener implements OnTouchListener { public boolean onTouch(View view, MotionEvent motionEvent) { if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) { ClipData data = ClipData.newPlainText("", ""); DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view); view.startDrag(data, shadowBuilder, view, 0); view.setVisibility(View.INVISIBLE); return true; } else { return false; } } } class MyDragListener implements OnDragListener { //Drawable enterShape = getResources().getDrawable(R.drawable.shape_droptarget); //Drawable normalShape = getResources().getDrawable(R.drawable.shape); @Override public boolean onDrag(View v, DragEvent event) { switch (event.getAction()) { case DragEvent.ACTION_DRAG_LOCATION: if(v != iv3) v.setVisibility(View.VISIBLE); break; case DragEvent.ACTION_DRAG_STARTED: // Do nothing break; case DragEvent.ACTION_DRAG_ENTERED: break; case DragEvent.ACTION_DRAG_EXITED: break; case DragEvent.ACTION_DROP: // Dropped, reassign View to ViewGroup //handle the dragged view being dropped over a drop view View view = (View) event.getLocalState(); Drawable dropshadow = getResources().getDrawable(R.drawable.dropshadow); //view dragged item is being dropped on ImageView dropTarget = (ImageView) v; //view being dragged and dropped ImageView dropped = (ImageView) view; /* //if an item has already been dropped here, there will be a tag Object tag = dropTarget.getTag(); //if there is already an item here, set it back visible in its original place if(tag!=null) { //the tag is the view id already dropped here int existingID = (Integer)tag; //set the original view visible again findViewById(existingID).setVisibility(View.VISIBLE); } //set the tag in the target view to the ID of the view being dropped dropTarget.setTag(dropped.getId()); */ String temp = "a"; if(temp.equals(view.getTag())){ //dropped.setBackground(dropshadow); dropTarget.setBackground(dropshadow); Log.d(temp, "Correct Image"); } else { Log.d("b", "Wrong Image"); view.setVisibility(View.VISIBLE); } break; case DragEvent.ACTION_DRAG_ENDED: default: break; } return true; } }

What am I missing in here? Any help is truly appreciated. Thanks.

解决方案

Finally I solved this myself. I added this method:

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

and added this:

case DragEvent.ACTION_DRAG_ENDED: if (dropEventNotHandled(event)) view.setVisibility(View.VISIBLE); break;