代码：流式布局FlowLayout

1.代码：

package extra.view;

import android.content.Context;import android.util.AttributeSet;import android.util.Log;import android.view.View;import android.view.ViewGroup;

import java.util.ArrayList;import java.util.List;

public class FlowLayout extends ViewGroup{

private static final String TAG = "FlowLayout";

public FlowLayout(Context context, AttributeSet attrs)   {      super(context, attrs);   }

@Override   protected LayoutParams generateLayoutParams(         LayoutParams p)   {      return new MarginLayoutParams(p);   }

@Override   public LayoutParams generateLayoutParams(AttributeSet attrs)   {      return new MarginLayoutParams(getContext(), attrs);   }

@Override   protected LayoutParams generateDefaultLayoutParams()   {      return new MarginLayoutParams(LayoutParams.MATCH_PARENT,            LayoutParams.MATCH_PARENT);   }

/**    * 负责设置子控件的测量模式和大小 根据所有子控件设置自己的宽和高    */   @Override   protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)   {      super.onMeasure(widthMeasureSpec, heightMeasureSpec);      // 获得它的父容器为它设置的测量模式和大小      int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);      int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);      int modeWidth = MeasureSpec.getMode(widthMeasureSpec);      int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

Log.e(TAG, sizeWidth + "," + sizeHeight);

// 如果是warp_content情况下，记录宽和高      int width = 0;      int height = 0;      /**       * 记录每一行的宽度，width不断取最大宽度       */      int lineWidth = 0;      /**       * 每一行的高度，累加至height       */      int lineHeight = 0;

int cCount = getChildCount();

// 遍历每个子元素      for (int i = 0; i < cCount; i++)      {         View child = getChildAt(i);         // 测量每一个child的宽和高         measureChild(child, widthMeasureSpec, heightMeasureSpec);         // 得到child的lp         MarginLayoutParams lp = (MarginLayoutParams) child               .getLayoutParams();         // 当前子空间实际占据的宽度         int childWidth = child.getMeasuredWidth() + lp.leftMargin               + lp.rightMargin;         // 当前子空间实际占据的高度         int childHeight = child.getMeasuredHeight() + lp.topMargin               + lp.bottomMargin;         /**          * 如果加入当前child，则超出最大宽度，则的到目前最大宽度给width，类加height 然后开启新行          */         if (lineWidth + childWidth > sizeWidth)         {            width = Math.max(lineWidth, childWidth);// 取最大的            lineWidth = childWidth; // 重新开启新行，开始记录            // 叠加当前高度，            height += lineHeight;            // 开启记录下一行的高度            lineHeight = childHeight;         } else         // 否则累加值lineWidth,lineHeight取最大高度         {            lineWidth += childWidth;            lineHeight = Math.max(lineHeight, childHeight);         }         // 如果是最后一个，则将当前记录的最大宽度和当前lineWidth做比较         if (i == cCount - 1)         {            width = Math.max(width, lineWidth);            height += lineHeight;         }

}      setMeasuredDimension((modeWidth == MeasureSpec.EXACTLY) ? sizeWidth            : width, (modeHeight == MeasureSpec.EXACTLY) ? sizeHeight            : height);

}   /**    * 存储所有的View，按行记录    */   private List<List<View>> mAllViews = new ArrayList<List<View>>();   /**    * 记录每一行的最大高度    */   private List<Integer> mLineHeight = new ArrayList<Integer>();   @Override   protected void onLayout(boolean changed, int l, int t, int r, int b)   {      mAllViews.clear();      mLineHeight.clear();

int width = getWidth();

int lineWidth = 0;      int lineHeight = 0;      // 存储每一行所有的childView      List<View> lineViews = new ArrayList<View>();      int cCount = getChildCount();      // 遍历所有的孩子      for (int i = 0; i < cCount; i++)      {         View child = getChildAt(i);         MarginLayoutParams lp = (MarginLayoutParams) child               .getLayoutParams();         int childWidth = child.getMeasuredWidth();         int childHeight = child.getMeasuredHeight();

// 如果已经需要换行         if (childWidth + lp.leftMargin + lp.rightMargin + lineWidth > width)         {            // 记录这一行所有的View以及最大高度            mLineHeight.add(lineHeight);            // 将当前行的childView保存，然后开启新的ArrayList保存下一行的childView            mAllViews.add(lineViews);            lineWidth = 0;// 重置行宽            lineViews = new ArrayList<View>();         }         /**          * 如果不需要换行，则累加          */         lineWidth += childWidth + lp.leftMargin + lp.rightMargin;         lineHeight = Math.max(lineHeight, childHeight + lp.topMargin               + lp.bottomMargin);         lineViews.add(child);      }      // 记录最后一行      mLineHeight.add(lineHeight);      mAllViews.add(lineViews);

int left = 0;      int top = 0;      // 得到总行数      int lineNums = mAllViews.size();      for (int i = 0; i < lineNums; i++)      {         // 每一行的所有的views         lineViews = mAllViews.get(i);         // 当前行的最大高度         lineHeight = mLineHeight.get(i);

Log.e(TAG, "第" + i + "行 ：" + lineViews.size() + " , " + lineViews);         Log.e(TAG, "第" + i + "行， ：" + lineHeight);

// 遍历当前行所有的View         for (int j = 0; j < lineViews.size(); j++)         {            View child = lineViews.get(j);            if (child.getVisibility() == View.GONE)            {               continue;            }            MarginLayoutParams lp = (MarginLayoutParams) child                  .getLayoutParams();

//计算childView的left,top,right,bottom            int lc = left + lp.leftMargin;            int tc = top + lp.topMargin;            int rc =lc + child.getMeasuredWidth();            int bc = tc + child.getMeasuredHeight();

Log.e(TAG, child + " , l = " + lc + " , t = " + t + " , r ="                  + rc + " , b = " + bc);

child.layout(lc, tc, rc, bc);

left += child.getMeasuredWidth() + lp.rightMargin                  + lp.leftMargin;         }         left = 0;         top += lineHeight;      }

}}

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