Android实现滑动删除操作（PopupWindow）

public class MyListView extends ListView { private static final String TAG = "MyListView"; private int mTouchSlop; private int mXDown; private int mYDown; private int mCurrentPosition; private View mCurrentView; private PopupWindow mPopupWindow; private LayoutInflater mInflater; private boolean isSliding = false; // 为删除按钮提供一个回调接口 private DelButtonClickListener mListener; private Button mDelBtn; private int mPopupWindowHeight; private int mPopupWindowWidth; public MyListView(Context context, AttributeSet attrs) {  super(context, attrs);  mInflater = LayoutInflater.from(context);  mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();  View view = mInflater.inflate(R.layout.delete_btn, null);  mDelBtn = (Button) view.findViewById(R.id.id_item_btn);  mPopupWindow = new PopupWindow(view, LinearLayout.LayoutParams.WRAP_CONTENT,    LinearLayout.LayoutParams.WRAP_CONTENT);  // 如果需要通过点击PopupWindow之外的地方使其消失，则需要setFocusable(true).  mPopupWindow.setFocusable(true);  // Android 6.0以前的版本需要setBackgroundDrawable()，  // 才能实现通过点击PopupWindow之外的地方使其消失的功能。  mPopupWindow.setBackgroundDrawable(new ColorDrawable(0));  // 先调用下measure，否则拿不到宽和高  mPopupWindow.getContentView().measure(0, 0);  mPopupWindowHeight = mPopupWindow.getContentView().getMeasuredHeight();  mPopupWindowWidth = mPopupWindow.getContentView().getMeasuredWidth(); } @Override public boolean onTouchEvent(MotionEvent ev) {  int action = ev.getAction();  int x = (int) ev.getX();  int y = (int) ev.getY();  switch (action){   case MotionEvent.ACTION_DOWN:    isSliding = false;    mXDown = x;    mYDown = y;    mCurrentPosition = pointToPosition(mXDown, mYDown);    View view = getChildAt(mCurrentPosition - getFirstVisiblePosition());    mCurrentView = view;    break;   case MotionEvent.ACTION_MOVE:    int dx = x - mXDown;    int dy = y - mYDown;    Log.d(TAG, "mTouchSlop = " + mTouchSlop + ", dx = " + dx + ", dy = " + dy);    if(mXDown > x && Math.abs(dx) > mTouchSlop && Math.abs(dy) < mTouchSlop){     Log.d(TAG, "isSliding");     isSliding = true;     int[] location = new int[2];     mCurrentView.getLocationOnScreen(location);     mPopupWindow.setAnimationStyle(R.style.popwindow_delete_btn_anim_style);     mPopupWindow.update();     Log.d(TAG, "Height: " + mCurrentView.getHeight() + "," + mPopupWindow.getHeight());     mPopupWindow.showAtLocation(mCurrentView, Gravity.NO_GRAVITY,       location[0] + mCurrentView.getWidth(),       location[1] + mCurrentView.getHeight() / 2 - mPopupWindowHeight / 2);     mDelBtn.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {       mListener.clickHappend(mCurrentPosition);       mPopupWindow.dismiss();      }     });    }   case MotionEvent.ACTION_UP:    // isSliding 如果这里恢复为false,则后面会执行super.onTouchEvent事件，    // 而AbsListView的onTouchEvent调用了onTouchUp方法，在onTouchUp方法中有可能执行    // performClick.run() --> performItemClick() --> super.performItemClick    // --> mOnItemClickListener.onItemClick，这样最终触发Item的点击。    // 因此此处依旧保持isSliding为true的状态，而在ACTION_DOWN事件中恢复isSliding为false，    // 毕竟每个事件都以ACTION_DOWN开始。    //isSliding = false;  }  if(isSliding){   return true;  }  return super.onTouchEvent(ev); } public void setDelButtonClickListener(DelButtonClickListener listener){  mListener = listener; } interface DelButtonClickListener{  public void clickHappend(int position); }}