上一篇文章《自定义viewgroup（2）》地址：http://www.jb51.net/article/100610.htm
代码
package com.example.libingyuan.horizontallistview.ScrollViewGroup; import android.content.Context; import android.util.AttributeSet; import android.util.DisplayMetrics; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.WindowManager; import android.widget.Scroller; /** * 自定义ViewGroup * 在滚动的基础上，增加了边界限制 */ public class ScrollViewGroup extends ViewGroup { //滚动计算辅助类 private Scroller mScroller; //手指落点的X坐标 private float mLastMotionX = 0; //屏幕宽度 private int screenWidth; /** * 使用new关键字创建对象的时候调用 * @param context 上下文 */ public ScrollViewGroup(Context context) { this(context, null); } /** * 在XML文件中使用的时候调用 * @param context 上下文 * @param attrs 属性：如 android:layout_width="wrap_content" */ 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 * @param context 上下文 * @param attrs 属性：如 android:layout_width="wrap_content" * @param defStyleAttr 自定义属性的id */ 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 * @param context */ private void init(Context context) { mScroller = new Scroller(context); WindowManager manager = (WindowManager) context .getSystemService(Context.WINDOW_SERVICE); DisplayMetrics outMetrics = new DisplayMetrics(); manager.getDefaultDisplay().getMetrics(outMetrics); screenWidth = outMetrics.widthPixels; } /** * 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 * @param event * @return */ @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub int action = event.getAction(); float x = event.getX(); switch (action) { case MotionEvent.ACTION_DOWN: if (!mScroller.isFinished()) { mScroller.abortAnimation(); } mLastMotionX = event.getX(); break; case MotionEvent.ACTION_MOVE: float delt = mLastMotionX - x; mLastMotionX = x; scrollBy((int) delt, 0); break; case MotionEvent.ACTION_UP: View lastChild=getChildAt(getChildCount()-1); int finalyChild= (int) (lastChild.getX()+lastChild.getWidth()-screenWidth); if (getScrollX()<0){ scrollTo(0,0); } if (getScrollX()>=finalyChild) scrollTo(finalyChild,0); invalidate(); break; default: break; } return true; } @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); } }
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