Android自定义ViewGroup横向布局（1）

package com.example.libingyuan.horizontallistview.ScrollViewGroup;import android.content.Context;import android.util.AttributeSet;import android.view.View;import android.view.ViewGroup;/** * 自定义ViewGroup * 很简单的横向布局，把所有的子View都横着排列起来，不可滚动 */public class ScrollViewGroup extends ViewGroup{  public ScrollViewGroup(Context context) {    this(context,null);  }  public ScrollViewGroup(Context context, AttributeSet attrs) {    this(context, attrs,0);  }  public ScrollViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);  }  @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);    //宽度的类型    int modeWidth = MeasureSpec.getMode(widthMeasureSpec);    //父控件的宽（wrap_content）    int width = 0;    //子View的个数    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++) {      //获取子View      View child = getChildAt(i);      //测量子View，无论什么模式，这句必须有否则界面不显示子View（一片空白）      measureChild(child, widthMeasureSpec, heightMeasureSpec);      //得到子View的边距      MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();      //得到宽度      int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;      //宽度累加      width += childWidth;    }    //返回宽度    return modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width;  }  /**   * 测量高度   */  private int measureHeight(int widthMeasureSpec, int heightMeasureSpec) {    //高度    int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);    //高度的模式    int modeHeight = MeasureSpec.getMode(heightMeasureSpec);    //父控件的高（wrap_content）    int height = 0;    //子View的个数    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++) {      //得到子View      View child = getChildAt(i);      //测量      measureChild(child, widthMeasureSpec, heightMeasureSpec);      //得到边距      MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();      //得到高度      int childHeight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;      //累加高度      height += childHeight;    }    //求平均高度    height = height / childCount;    //返回高度    return modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height;  }  @Override  protected void onLayout(boolean changed, int l, int t, int r, int b) {    int childLeft=0;//子View左边的距离    int childWidth;//子View的宽度    int height=getHeight();    int childCount=getChildCount();    for (int i = 0; i < childCount; i++) {      View child=getChildAt(i);      MarginLayoutParams lp= (MarginLayoutParams) child.getLayoutParams();      childWidth=child.getMeasuredWidth()+lp.leftMargin+lp.rightMargin;      //最主要的一句话      child.layout(childLeft,0,childLeft+childWidth,height);      childLeft+=childWidth;    }  }  @Override  public LayoutParams generateLayoutParams(AttributeSet attrs) {    return new MarginLayoutParams(getContext(),attrs);  }}