自定义实现瀑布流布局

简单的瀑布流布局
用法：
new 一个出来后，直接往里面add（View）就行

是不是很简单，哈哈

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

    import android.content.Context;
    import android.util.AttributeSet;
    import android.util.Log;
    import android.view.View;
    import android.view.ViewGroup;
    public class FlowLayout extends ViewGroup {

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

    public FlowLayout(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public FlowLayout(Context context) {
        this(context, null);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
        int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
        int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
        int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

        int width = 0;
        int height = 0;

        // 每一行的宽度和高度
        int lineWidth = 0;
        int lineHeight = 0;

        int cCount = getChildCount();
        for (int i = 0; i < cCount; i++) {
            View child = getChildAt(i);
            // 测量子view的宽和高
            measureChild(child, widthMeasureSpec, heightMeasureSpec);
            MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

            int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
            int childHeight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;

            if (lineWidth + childWidth > sizeWidth - getPaddingLeft() - getPaddingRight()) {
                width = Math.max(width, lineWidth);
                lineWidth = childWidth;

                height += lineHeight;
                lineHeight = childHeight;
            } else {// 未换行
                lineWidth += childWidth;
                lineHeight = Math.max(lineHeight, childHeight);
            }
            if (i == cCount-1) {
                width = Math.max(lineWidth, width);//最后一行，再计算一下最大宽度
                height += lineHeight;//后边这两行是为了给下面的广告留位置
                height += lineHeight;
            }
        }
        setMeasuredDimension(modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width + getPaddingLeft() + getPaddingRight(), modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height + getPaddingTop() + getPaddingBottom());
    }

    private List> mAllViews = new ArrayList>();
    private List mLineHeight = new ArrayList();

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        mAllViews.clear();
        mLineHeight.clear();
        int width = getWidth();
    //      int height = getHeight();

        int lineWidth = 0;
        int lineHeight = 0;
        List lineViews = new ArrayList();
        int cCount = getChildCount();
        for (int i = 0; i < cCount; i++) {
            View child = getChildAt(i);
            MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

            int childWidth = child.getMeasuredWidth();
            int childHeight = child.getMeasuredHeight();
            // 需要换行
            if (childWidth + lineWidth + lp.leftMargin + lp.rightMargin > width - getPaddingLeft() - getPaddingRight()) {
    //              Log.e("aaaa", "需要换行了");
                mLineHeight.add(lineHeight);
                mAllViews.add(lineViews);
                // 重置行宽和行高
                lineWidth = 0;
                lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
                lineViews = new ArrayList();
            }
            lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
            lineHeight = Math.max(lineHeight, childHeight + lp.topMargin + lp.bottomMargin);
            lineViews.add(child);
        }// for end
            // 处理最生一行
        mLineHeight.add(lineHeight);
        mAllViews.add(lineViews);

        int left = getPaddingLeft();
        int top = getPaddingTop();

        int lineNum = mAllViews.size();
        for (int i = 0; i < lineNum; i++) {
            lineViews = mAllViews.get(i);
            lineHeight = mLineHeight.get(i);
            for(int j=0; jint lc = left +lp.leftMargin;
                int tc = top + lp.topMargin;
                int rc = lc + child.getMeasuredWidth();
                int bc = tc + child.getMeasuredHeight();
                child.layout(lc, tc, rc, bc);
                left += child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
            }
            left = getPaddingLeft();
            top += lineHeight;
        }

    }

    /**
     * 与当前ViewGroup对应的layoutParams
     */
    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new MarginLayoutParams(getContext(), attrs);
    }
    }