1、触摸事件 dispatchTouchEvent 判断是否处理触摸动作 onTouchEvent 处理触摸动作
2、Android对于控制和获取View在屏幕很强大
ListView：
pointToPosition 根据触摸点获取item的位置
getChildAt 根据索引获取item的View，注意从第一个可视化的item算起
View：
getLocationOnScreen获取View在屏幕的坐标
import android.content.Context;import android.util.AttributeSet;import android.view.Gravity;import android.view.LayoutInflater;import android.view.MotionEvent;import android.view.View;import android.view.ViewConfiguration;import android.widget.Button;import android.widget.LinearLayout;import android.widget.ListView;import android.widget.PopupWindow;public class MyListView extends ListView{private static final String TAG = "MyListView";// private static final int VELOCITY_SANP = 200;// private VelocityTracker mVelocityTracker;/*** 用户滑动的最小距离*/private int touchSlop;/*** 是否响应滑动*/private boolean isSliding;/*** 手指按下时的x坐标*/private int xDown;/*** 手指按下时的y坐标*/private int yDown;/*** 手指移动时的x坐标*/private int xMove;/*** 手指移动时的y坐标*/private int yMove;private LayoutInflater mInflater;private PopupWindow mPopupWindow;private int mPopupWindowHeight;private int mPopupWindowWidth;private Button mDelBtn;/*** 为删除按钮提供一个回调接口*/private DelButtonClickListener mListener;/*** 当前手指触摸的View*/private View mCurrentView;/*** 当前手指触摸的位置*/private int mCurrentViewPos;/*** 必要的一些初始化** @param context* @param attrs*/public MyListView(Context context, AttributeSet attrs){super(context, attrs);mInflater = LayoutInflater.from(context);// 获取设备所支持的最小滑动距离touchSlop = ViewConfiguration.get(context).getScaledTouchSlop();View view = mInflater.inflate(R.layout.button_list, null);mDelBtn = (Button) view.findViewById(R.id.id_item_btn1);// mPopupWindow = new PopupWindow(view, LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);/*** 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 dispatchTouchEvent(MotionEvent ev){int action = ev.getAction();int x = (int) ev.getX();int y = (int) ev.getY();switch (action){case MotionEvent.ACTION_DOWN:xDown = x;yDown = y;/*** 如果当前popupWindow显示，则直接隐藏，然后屏蔽ListView的touch事件的下传*/if (mPopupWindow.isShowing()){dismissPopWindow();return false;}// 获得当前手指按下时的item的位置mCurrentViewPos = pointToPosition(xDown, yDown);// 获得当前手指按下时的itemView view = getChildAt(mCurrentViewPos - getFirstVisiblePosition());mCurrentView = view;break;case MotionEvent.ACTION_MOVE:xMove = x;yMove = y;int dx = xMove - xDown;int dy = yMove - yDown;/*** 判断是否是从右到左的滑动*/if (xMove < xDown && Math.abs(dx) > touchSlop && Math.abs(dy) < touchSlop){// Log.e(TAG, "touchslop = " + touchSlop + " , dx = " + dx +// " , dy = " + dy);isSliding = true;}break;}return super.dispatchTouchEvent(ev);}@Overridepublic boolean onTouchEvent(MotionEvent ev){int action = ev.getAction();/*** 如果是从右到左的滑动才相应*/if (isSliding){switch (action){case MotionEvent.ACTION_MOVE:int[] location = new int[2];// 获得当前item的位置x与ymCurrentView.getLocationOnScreen(location);// 设置popupWindow的动画mPopupWindow.setAnimationStyle(R.style.button_anim_style);mPopupWindow.update();mPopupWindow.showAtLocation(mCurrentView, Gravity.LEFT | Gravity.TOP,location[0] + mCurrentView.getWidth(), location[1]);// + mCurrentView.getHeight() / 2 - mPopupWindowHeight / 2);// 设置删除按钮的回调mDelBtn.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View v){if (mListener != null){mListener.clickHappend(mCurrentViewPos);mPopupWindow.dismiss();}}});// Log.e(TAG, "mPopupWindow.getHeight()=" + mPopupWindowHeight);break;case MotionEvent.ACTION_UP:isSliding = false;}// 相应滑动期间屏幕itemClick事件，避免发生冲突return true;}return super.onTouchEvent(ev);}/*** 隐藏popupWindow*/private void dismissPopWindow(){if (mPopupWindow != null && mPopupWindow.isShowing()){mPopupWindow.dismiss();}}public void setDelButtonClickListener(DelButtonClickListener listener){mListener = listener;}interface DelButtonClickListener{public void clickHappend(int position);}}
