GridView长按拖拽Item及自动滚屏效果

package com.pl; import com.pl.MainActivity.ImageAdapter; import android.content.Context; import android.graphics.Bitmap; 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 DragGridView extends GridView { private int dragPosition; // 开始拖拽的位置 private int dropPosition; // 结束拖拽的位置 private int dragPointX; // 相对于item的x坐标 private int dragPointY; // 相对于item的y坐标 private int dragOffsetX; private int dragOffsetY; private ImageView dragImageView; // 拖动item的preview private WindowManager windowManager; private WindowManager.LayoutParams windowParams; private int itemHeight; public DragGridView(Context context, AttributeSet attrs) { super(context, attrs); } boolean flag = false; public void setLongFlag(boolean temp) { flag = temp; } public boolean setOnItemLongClickListener(final MotionEvent ev) { this.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() { @Override public boolean onItemLongClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) { // onInterceptTouchEvent(ev); // TODO Auto-generated method stub L.l("============on Long Click========="); L.l("============X:" + ev.getX() + " Y:" + ev.getY()); int x = (int) ev.getX(); int y = (int) ev.getY(); L.l("============X:" + x + " Y:" + y); dragPosition = dropPosition = pointToPosition(x, y); System.out.println(dragPosition); if (dragPosition == AdapterView.INVALID_POSITION) { } ViewGroup itemView = (ViewGroup) getChildAt(dragPosition - getFirstVisiblePosition()); // 得到当前点在item内部的偏移量 即相对于item左上角的坐标 dragPointX = x - itemView.getLeft(); dragPointY = y - itemView.getTop(); dragOffsetX = (int) (ev.getRawX() - x); dragOffsetY = (int) (ev.getRawY() - y); itemHeight=itemView.getHeight(); L.l("========================y:" + y + " getRawY:" + ev.getRawY()); // 解决问题3 // 每次都销毁一次cache，重新生成一个bitmap itemView.destroyDrawingCache(); itemView.setDrawingCacheEnabled(true); Bitmap bm = Bitmap.createBitmap(itemView.getDrawingCache()); // 建立item的缩略图 startDrag(bm, x, y); 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); } private void startDrag(Bitmap bm, int x, int y) { stopDrag(); windowParams = new WindowManager.LayoutParams(); System.out.println("X: " + x + " dragPointX: " + dragPointX + " dragOffsetX: " + dragOffsetX); windowParams.gravity = Gravity.TOP | Gravity.LEFT;// 这个必须加 // 得到preview左上角相对于屏幕的坐标 windowParams.x = x - dragPointX + dragOffsetX; windowParams.y = y - dragPointY + dragOffsetY; // L.l("==================windowParams.y==============="+windowParams.y); // 设置宽和高 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 iv = new ImageView(getContext()); iv.setImageBitmap(bm); windowManager = (WindowManager) getContext().getSystemService( Context.WINDOW_SERVICE);// "window" windowManager.addView(iv, windowParams); dragImageView = iv; } @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_MOVE: onDrag(x, y); break; case MotionEvent.ACTION_UP: stopDrag(); onDrop(x, y); break; } } return super.onTouchEvent(ev); } private void onDrag(int x, int y) { if (dragImageView != null) { windowParams.alpha = 0.6f; windowParams.x = x - dragPointX + dragOffsetX; windowParams.y = y - dragPointY + dragOffsetY; // L.l("=================windowParams.y=====000========"+windowParams.y); windowManager.updateViewLayout(dragImageView, windowParams); } int tempScrollX = x - dragPointX + dragOffsetX; int tempScrollY = y - dragPointY + dragOffsetY; if (tempScrollY +itemHeight> 600) { this.scrollTo(0, tempScrollY); } else if (pointToPosition(x, y) > 2) { this.scrollTo(0, tempScrollY - 300); } } private void onDrop(int x, int y) { int tempPosition = pointToPosition(x, y); if (tempPosition != AdapterView.INVALID_POSITION) { dropPosition = tempPosition; } if (dropPosition != dragPosition) { System.out.println("dragPosition: " + dragPosition + " dropPosition: " + dropPosition); ImageAdapter adapter = (ImageAdapter) this.getAdapter(); adapter.exchange(dragPosition, dropPosition); // 解决问题3 /* * ViewGroup itemView1 = (ViewGroup)getChildAt(dragPosition - getFirstVisiblePosition()); ViewGroup * itemView2 = (ViewGroup)getChildAt(dropPosition - getFirstVisiblePosition()); * itemView1.destroyDrawingCache(); itemView2.destroyDrawingCache(); */ } } private void stopDrag() { if (dragImageView != null) { windowManager.removeView(dragImageView); dragImageView = null; } } }