Android程序开发之ListView与PopupWindow实现从左向右滑动删除功能

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)  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);
}
}