Android: drag the GridView to the target View

[Java]
Package cn.com. weather. serviceDemo. view;
 
Import cn.com. weather. serviceDemo. interfaces. OnDropListener;
Import cn.com. weather. serviceDemo. util. DeviceUtil;
Import android. content. Context;
Import android. graphics. Bitmap;
Import android. graphics. Matrix;
Import android. graphics. PixelFormat;
Import android. util. AttributeSet;
Import android. view. Gravity;
Import android. view. MotionEvent;
Import android. view. View;
Import android. view. ViewGroup;
Import android. view. WindowManager;
Import android. widget. AdapterView;
Import android. widget. GridView;
Import android. widget. ImageView;
 
Public class MyGridView extends GridView {

Private ImageView dragImageView;
Private WindowManager windowManager;
Private WindowManager. LayoutParams windowParams;

Private int dragSrcPosition; // start to drag an item.
Private int dragPosition;

// The position to move
Private int dragPointX;
Private int dragPointY;
// The distance from the current position to the Boundary
Private int dragOffsetX;
Private int dragOffsetY;

Private View myView; // target view
Private int dropPosition =-1; // selected

Private OnDropListener onDropListener;
 
Public MyGridView (Context context, AttributeSet attrs ){
Super (context, attrs );
}

Public void setView (View view ){
MyView = view;
}

Public void setOnDropListener (OnDropListener onDropListener ){
This. onDropListener = onDropListener;
}

Private boolean setOnItemLongClickListener (final MotionEvent ev ){
This. setOnItemLongClickListener (new OnItemLongClickListener (){
 
@ Override
Public boolean onItemLongClick (AdapterView <?> Parent, View view,
Int position, long id ){
Final int x = (int) ev. getX (); // the coordinate of the touch point relative to the GridView
Final int y = (int) ev. getY ();

DragSrcPosition = dragPosition = position;

If (dragPosition = AdapterView. INVALID_POSITION ){
Return false;
}

Final ViewGroup item = (ViewGroup) getChildAt (dragPosition-getFirstVisiblePosition ());

DragPointX = x-item. getLeft ();
DragPointY = y-item. getTop ();
DragOffsetX = (int) ev. getRawX ()-x;
DragOffsetY = (int) ev. getRawY ()-y;

Item. destroyDrawingCache (); // clear the cache
Item. setDrawingCacheEnabled (true );
Bitmap bitmap = Bitmap. createBitmap (item. getDrawingCache ());
StartDrag (getScaleBitmap (bitmap), x, y );
DeviceUtil. Vibrate (getContext (), 100 );
Return false;
}
});

Return super. onInterceptTouchEvent (ev );
}
 
@ Override
Public boolean onInterceptTouchEvent (MotionEvent ev ){
If (ev. getAction () = MotionEvent. ACTION_DOWN ){
Return setOnItemLongClickListener (ev );
}
Return super. onInterceptTouchEvent (ev );
}

@ Override
Public boolean onTouchEvent (MotionEvent ev ){
If (dragImageView! = Null & dragPosition! = AdapterView. INVALID_POSITION ){
Int x = (int) ev. getX ();
Int y = (int) ev. getY ();
Switch (ev. getAction ()){
Case MotionEvent. ACTION_UP:
StopDrag ();
OnDrop (int) ev. getRawX (), (int) ev. getRawY ());
Break;
 
Case MotionEvent. ACTION_MOVE:
OnDrag (x, y );
Break;
}


}
Return super. onTouchEvent (ev );
}
 
Private void startDrag (Bitmap bm, int x, int y ){
StopDrag ();

WindowParams = new WindowManager. LayoutParams ();
WindowParams. gravity = Gravity. TOP | Gravity. LEFT;
// Coordinates of the upper left corner relative to the screen
WindowParams. x = x-dragPointX + dragOffsetX;
WindowParams. y = y-dragPointY + dragOffsetY;

WindowParams. height = WindowManager. LayoutParams. WRAP_CONTENT;
WindowParams. width = WindowManager. LayoutParams. WRAP_CONTENT;
WindowParams. flags = WindowManager. LayoutParams. FLAG_NOT_FOCUSABLE
| WindowManager. LayoutParams. FLAG_NOT_TOUCHABLE
| WindowManager. LayoutParams. FLAG_KEEP_SCREEN_ON
| WindowManager. LayoutParams. FLAG_LAYOUT_IN_SCREEN;
WindowParams. format = PixelFormat. TRANSLUCENT;
WindowParams. windowAnimations = 0;

ImageView imageView = new ImageView (this. getContext ());
ImageView. setImageBitmap (bm );

WindowManager = (WindowManager) this. getContext (). getSystemService (Context. WINDOW_SERVICE );
WindowManager. addView (imageView, windowParams );
DragImageView = imageView;
}

Private void stopDrag (){
If (dragImageView! = Null ){
WindowManager. removeView (dragImageView );
DragImageView = null;
}
}

Private void onDrag (int x, int y ){
If (dragImageView! = Null ){
WindowParams. alpha = 0.8f;
WindowParams. x = x-dragPointX + dragOffsetX;
WindowParams. y = y-dragPointY + dragOffsetY;
WindowManager. updateViewLayout (dragImageView, windowParams );
}

}

Private void onDrop (int x, int y ){
Boolean inView = isInView (x, y, myView );
If (inView ){
If (onDropListener! = Null ){
OnDropListener. onDrop (dragSrcPosition );
}
}
}

Private Bitmap getScaleBitmap (Bitmap bitmap ){
Matrix matrix = new Matrix ();
Matrix. postScale (1.1f, 1.1f );
Return Bitmap. createBitmap (bitmap, 0, 0, bitmap. getWidth (), bitmap. getHeight (), matrix, true );
}

Private boolean isInView (int x, int y, View view ){
If (view = null) return false;

Int [] location = new int [2];
View. getLocationInWindow (location );
Int _ x = location [0];
Int _ y = location [1];
Int width = view. getWidth ();
Int height = view. getHeight ();

If (_ x <x & x <_ x + width & _ y <y & y <_ y + height ){
Return true;
}
Return false;
}


 
}