Android拖放问题不显示 [英] Android drag and drop issue not displaying
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
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;
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