/*
* Copyright (C) 2010 Eric Harlow
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.ericharlow.DragNDrop;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.PixelFormat;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.ListView;
public class DragNDropListView extends ListView {
boolean mDragMode;
int mStartPosition;
int mEndPosition;
int mDragPointOffset; //Used to adjust drag view location
ImageView mDragView;
GestureDetector mGestureDetector;
DropListener mDropListener;
RemoveListener mRemoveListener;
DragListener mDragListener;
public DragNDropListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void setDropListener(DropListener l) {
mDropListener = l;
}
public void setRemoveListener(RemoveListener l) {
mRemoveListener = l;
}
public void setDragListener(DragListener l) {
mDragListener = l;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
final int x = (int) ev.getX();
final int y = (int) ev.getY();
if (action == MotionEvent.ACTION_DOWN && x < this.getWidth()/8) {
mDragMode = true;
}
if (!mDragMode)
return super.onTouchEvent(ev);
switch (action) {
case MotionEvent.ACTION_DOWN:
mStartPosition = pointToPosition(x,y);
if (mStartPosition != INVALID_POSITION) {
int mItemPosition = mStartPosition - getFirstVisiblePosition();
mDragPointOffset = y - getChildAt(mItemPosition).getTop();
mDragPointOffset -= ((int)ev.getRawY()) - y;
startDrag(mItemPosition,y);
drag(0,y);// replace 0 with x if desired
}
break;
case MotionEvent.ACTION_MOVE:
drag(0,y);// replace 0 with x if desired
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
default:
mDragMode = false;
mEndPosition = pointToPosition(x,y);
stopDrag(mStartPosition - getFirstVisiblePosition());
if (mDropListener != null && mStartPosition != INVALID_POSITION && mEndPosition != INVALID_POSITION)
mDropListener.onDrop(mStartPosition, mEndPosition);
break;
}
return true;
}
// move the drag view
private void drag(int x, int y) {
if (mDragView != null) {
WindowManager.LayoutParams layoutParams = (WindowManager.LayoutParams) mDragView.getLayoutParams();
layoutParams.x = x;
layoutParams.y = y - mDragPointOffset;
WindowManager mWindowManager = (WindowManager) getContext()
.getSystemService(Context.WINDOW_SERVICE);
mWindowManager.updateViewLayout(mDragView, layoutParams);
if (mDragListener != null)
mDragListener.onDrag(x, y, null);// change null to "this" when ready to use
}
}
// enable the drag view for dragging
private void startDrag(int itemIndex, int y) {
stopDrag(itemIndex);
View item = getChildAt(itemIndex);
if (item == null) return;
item.setDrawingCacheEnabled(true);
if (mDragListener != null)
mDragListener.onStartDrag(item);
// Create a copy of the drawing cache so that it does not get recycled
// by the framework when the list tries to clean up memory
Bitmap bitmap = Bitmap.createBitmap(item.getDrawingCache());
WindowManager.LayoutParams mWindowParams = new WindowManager.LayoutParams();
mWindowParams.gravity = Gravity.TOP;
mWindowParams.x = 0;
mWindowParams.y = y - mDragPointOffset;
mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
| WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
| WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS;
mWindowParams.format = PixelFormat.TRANSLUCENT;
mWindowParams.windowAnimations = 0;
Context context = getContext();
ImageView v = new ImageView(context);
v.setImageBitmap(bitmap);
WindowManager mWindowManager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
mWindowManager.addView(v, mWindowParams);
mDragView = v;
}
// destroy drag view
private void stopDrag(int itemIndex) {
if (mDragView != null) {
if (mDragListener != null)
mDragListener.onStopDrag(getChildAt(itemIndex));
mDragView.setVisibility(GONE);
WindowManager wm = (WindowManager)getContext().getSystemService(Context.WINDOW_SERVICE);
wm.removeView(mDragView);
mDragView.setImageDrawable(null);
mDragView = null;
}
}
// private GestureDetector createFlingDetector() {
// return new GestureDetector(getContext(), new SimpleOnGestureListener() {
// @Override
// public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
// float velocityY) {
// if (mDragView != null) {
// int deltaX = (int)Math.abs(e1.getX()-e2.getX());
// int deltaY = (int)Math.abs(e1.getY() - e2.getY());
//
// if (deltaX > mDragView.getWidth()/2 && deltaY < mDragView.getHeight()) {
// mRemoveListener.onRemove(mStartPosition);
// }
//
// stopDrag(mStartPosition - getFirstVisiblePosition());
//
// return true;
// }
// return false;
// }
// });
// }
}