应用源码之DragList(可拖拽移动的ListView).zip

package com.fengjian.test; 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.ViewConfiguration; import android.view.ViewGroup; import android.view.WindowManager; import android.widget.AdapterView; import android.widget.ImageView; import android.widget.ListView; import android.widget.Toast; import com.fengjian.test.DragListActivity.DragListAdapter; public class DragListView extends ListView { private ImageView dragImageView;//被拖拽的项，其实就是一个ImageView private int dragSrcPosition;//手指拖动项原始在列表中的位置 private int dragPosition;//手指拖动的时候，当前拖动项在列表中的位置 private int dragPoint;//在当前数据项中的位置 private int dragOffset;//当前视图和屏幕的距离(这里只使用了y方向上) private WindowManager windowManager;//windows窗口控制类 private WindowManager.LayoutParams windowParams;//用于控制拖拽项的显示的参数 private int scaledTouchSlop;//判断滑动的一个距离 private int upScrollBounce;//拖动的时候，开始向上滚动的边界 private int downScrollBounce;//拖动的时候，开始向下滚动的边界 public DragListView(Context context, AttributeSet attrs) { super(context, attrs); scaledTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop(); } //拦截touch事件，其实就是加一层控制 @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if(ev.getAction()==MotionEvent.ACTION_DOWN){ int x = (int)ev.getX(); int y = (int)ev.getY(); dragSrcPosition = dragPosition = pointToPosition(x, y); if(dragPosition==AdapterView.INVALID_POSITION){ return super.onInterceptTouchEvent(ev); } ViewGroup itemView = (ViewGroup) getChildAt(dragPosition-getFirstVisiblePosition()); dragPoint = y - itemView.getTop(); dragOffset = (int) (ev.getRawY() - y); View dragger = itemView.findViewById(R.id.drag_list_item_image); if(dragger!=null&&x>dragger.getLeft()-20){ // upScrollBounce = Math.min(y-scaledTouchSlop, getHeight()/3); downScrollBounce = Math.max(y+scaledTouchSlop, getHeight()*2/3); itemView.setDrawingCacheEnabled(true); Bitmap bm = Bitmap.createBitmap(itemView.getDrawingCache()); startDrag(bm, y); } return false; } return super.onInterceptTouchEvent(ev); } /** * 触摸事件 */ @Override public boolean onTouchEvent(MotionEvent ev) { if(dragImageView!=null&&dragPosition!=INVALID_POSITION){ int action = ev.getAction(); switch(action){ case MotionEvent.ACTION_UP: int upY = (int)ev.getY(); stopDrag(); onDrop(upY); break; case MotionEvent.ACTION_MOVE: int moveY = (int)ev.getY(); onDrag(moveY); break; default:break; } return true; } //也决定了选中的效果 return super.onTouchEvent(ev); } /** * 准备拖动，初始化拖动项的图像 * @param bm * @param y */ public void startDrag(Bitmap bm ,int y){ stopDrag(); windowParams = new WindowManager.LayoutParams(); windowParams.gravity = Gravity.TOP; windowParams.x = 0; windowParams.y = y - dragPoint + dragOffset; windowParams.width = WindowManager.LayoutParams.WRAP_CONTENT; windowParams.height = 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(getContext()); imageView.setImageBitmap(bm); windowManager = (WindowManager)getContext().getSystemService("window"); windowManager.addView(imageView, windowParams); dragImageView = imageView; } /** * 停止拖动，去除拖动项的头像 */ public void stopDrag(){ if(dragImageView!=null){ windowManager.removeView(dragImageView); dragImageView = null; } } /** * 拖动执行，在Move方法中执行 * @param y */ public void onDrag(int y){ if(dragImageView!=null){ windowParams.alpha = 0.8f; windowParams.y = y - dragPoint + dragOffset; windowManager.updateViewLayout(dragImageView, windowParams); } //为了避免滑动到分割线的时候，返回-1的问题 int tempPosition = pointToPosition(0, y); if(tempPosition!=INVALID_POSITION){ dragPosition = tempPosition; } //滚动 int scrollHeight = 0; if(y<upScrollBounce){ scrollHeight = 8;//定义向上滚动8个像素，如果可以向上滚动的话 }else if(y>downScrollBounce){ scrollHeight = -8;//定义向下滚动8个像素，，如果可以向上滚动的话 } if(scrollHeight!=0){ //真正滚动的方法setSelectionFromTop() setSelectionFromTop(dragPosition, getChildAt(dragPosition-getFirstVisiblePosition()).getTop()+scrollHeight); } } /** * 拖动放下的时候 * @param y */ public void onDrop(int y){ //为了避免滑动到分割线的时候，返回-1的问题 int tempPosition = pointToPosition(0, y); if(tempPosition!=INVALID_POSITION){ dragPosition = tempPosition; } //超出边界处理 if(y<getChildAt(1).getTop()){ //超出上边界 dragPosition = 1; }else if(y>getChildAt(getChildCount()-1).getBottom()){ //超出下边界 dragPosition = getAdapter().getCount()-1; } //数据交换 if(dragPosition>0&&dragPosition<getAdapter().getCount()){ @SuppressWarnings("unchecked") DragListAdapter adapter = (DragListAdapter)getAdapter(); String dragItem = adapter.getItem(dragSrcPosition); adapter.remove(dragItem); adapter.insert(dragItem, dragPosition); Toast.makeText(getContext(), adapter.getList().toString(), Toast.LENGTH_SHORT).show(); } } }