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();}@Overridepublic 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() {@Overridepublic 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);}}