Android自定义viewgroup可滚动布局 GestureDetector手势监听（5）

package com.example.libingyuan.horizontallistview.ScrollViewGroup;import android.content.Context;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.view.GestureDetector;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.view.WindowManager;import android.widget.Scroller;/** * 自定义ViewGroup（横向滚动） */public class ScrollViewGroup extends ViewGroup { //滚动计算辅助类 private Scroller mScroller; //屏幕宽度 private int screenWidth; //可以移动的最大距离 private int mMaxDistance; //自定义手势监听类 private ScrollTouchLisener mTouchLisener; //手势监听 private GestureDetector mDetector; /**  * 使用new关键字创建对象的时候调用  */ public ScrollViewGroup(Context context) {  this(context, null); } /**  * 在XML文件中使用的时候调用  */ public ScrollViewGroup(Context context, AttributeSet attrs) {  this(context, attrs, 0); } /**  * 在xml文件中调用，并且使用了自定义属性的时候调用  */ public ScrollViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr);  init(context); } /**  * 初始化方法  * 初始化滚动辅助类Scroller以及计算出屏幕宽度  */ private void init(Context context) {  //初始化辅助类  mScroller = new Scroller(context);  //获取屏幕宽度  WindowManager manager = (WindowManager) context    .getSystemService(Context.WINDOW_SERVICE);  DisplayMetrics outMetrics = new DisplayMetrics();  manager.getDefaultDisplay().getMetrics(outMetrics);  screenWidth = outMetrics.widthPixels;  //手势指示器初始化  mTouchLisener = new ScrollTouchLisener();  mDetector = new GestureDetector(context, mTouchLisener); } /**  * 滚动时需要重写的方法，用于控制滚动  */ @Override public void computeScroll() {  //判断滚动时候停止  if (mScroller.computeScrollOffset()) {   //滚动到指定的位置   scrollTo(mScroller.getCurrX(), mScroller.getCurrY());   //这句话必须写，否则不能实时刷新   postInvalidate();  } } /**  * 手指触屏事件监听  */ @Override public boolean onTouchEvent(MotionEvent event) {  mDetector.onTouchEvent(event);  if (event.getAction() == MotionEvent.ACTION_UP) {   this.onUp(event);  }  return true; } /*  *测量方法，测量父布局的宽度和高度  */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {  //重新设置宽高  this.setMeasuredDimension(measureWidth(widthMeasureSpec, heightMeasureSpec), measureHeight(widthMeasureSpec, heightMeasureSpec)); } /**  * 测量宽度  */ private int measureWidth(int widthMeasureSpec, int heightMeasureSpec) {  // 宽度  int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);  int modeWidth = MeasureSpec.getMode(widthMeasureSpec);  //父控件的宽（wrap_content）  int width = 0;  int childCount = getChildCount();  //重新测量子view的宽度，以及最大高度  for (int i = 0; i < childCount; i++) {   View child = getChildAt(i);   measureChild(child, widthMeasureSpec, heightMeasureSpec);   MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();   int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;   width += childWidth;  }  return modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width; } /**  * 测量高度  */ private int measureHeight(int widthMeasureSpec, int heightMeasureSpec) {  //高度  int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);  int modeHeight = MeasureSpec.getMode(heightMeasureSpec);  //父控件的高（wrap_content）  int height = 0;  int childCount = getChildCount();  //重新测量子view的宽度，以及最大高度  for (int i = 0; i < childCount; i++) {   View child = getChildAt(i);   measureChild(child, widthMeasureSpec, heightMeasureSpec);   MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();   int childHeight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;   height += childHeight;  }  height = height / childCount;  return modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height; } /**  * 给子布局设定位置  */ @Override protected void onLayout(boolean changed, int l, int t, int r, int b) {  int childLeft = 0;//子View左边的间距  int childWidth;//子View的宽度  int height = getHeight();//屏幕的宽度  int childCount = getChildCount();//子View的数量  for (int i = 0; i < childCount; i++) {   View child = getChildAt(i);   MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();   childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;   child.layout(childLeft, 0, childLeft + childWidth, height);   childLeft += childWidth;  } } @Override public LayoutParams generateLayoutParams(AttributeSet attrs) {  return new MarginLayoutParams(getContext(), attrs); } /*  *按下事件 ACTION_DOWN  */ public boolean onDown(MotionEvent e) {  //如果停止滚动则取消动画（即手指按下就停止滚动）  if (!mScroller.isFinished()) {   mScroller.abortAnimation();  }  return false; } /* *抬起事件 ACTION_UP */ public boolean onUp(MotionEvent e) {  //得到最后一个子View  View lastChild = getChildAt(getChildCount() - 1);  //获取滑动的最大滑动距离（最后一个Child的右边框的坐标减去屏幕的宽度）  int finalyChild = (int) (lastChild.getX() + lastChild.getWidth() - screenWidth);  mMaxDistance = finalyChild;  //如果滑动的距离小于第一个控件的最左边（0）则回弹至（0,0）点  if (getScrollX() < 0) {   scrollTo(0, 0);  }  //如果滑动的距离大于最大可滑动距离则滑动到最后一个子View  if (getScrollX() >= finalyChild)   scrollTo(finalyChild, 0);  //刷新界面  invalidate();  return false; } /*  *ACTION_DOWN 、短按不移动  */ public void onShowPress(MotionEvent e) { } /*  *短按ACTION_DOWN、ACTION_UP  */ public boolean onSingleTapUp(MotionEvent e) {  return false; } /*  *ACTION_DOWN 、慢滑动  */ public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {  //滚动  scrollBy((int) distanceX, 0);  return false; } // ACTION_DOWN 、长按不滑动 public void onLongPress(MotionEvent e) { } /*  *ACTION_DOWN 、快滑动、 ACTION_UP  */ public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {  mScroller.fling(getScrollX(), 0, (int) -velocityX, 0, 0, mMaxDistance, 0, 0);  return false; } /**  * 自定义手势监听类  */ private class ScrollTouchLisener implements GestureDetector.OnGestureListener {  //按下事件  @Override  public boolean onDown(MotionEvent e) {   return ScrollViewGroup.this.onDown(e);  }  //单击事件  @Override  public void onShowPress(MotionEvent e) {   ScrollViewGroup.this.onShowPress(e);  }  //手指抬起事件  @Override  public boolean onSingleTapUp(MotionEvent e) {   return ScrollViewGroup.this.onSingleTapUp(e);  }  //滚动事件  @Override  public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {   return ScrollViewGroup.this.onScroll(e1, e2, distanceX, distanceY);  }  //长按事件  @Override  public void onLongPress(MotionEvent e) {   ScrollViewGroup.this.onLongPress(e);  }  //滑动事件  @Override  public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {   return ScrollViewGroup.this.onFling(e1, e2, velocityX, velocityY);  } }}