流式布局

XML中的布局代码：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity"
   >
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="热搜"/>

    <com.example.lian0322_1.NewClass
        android:layout_width="match_parent"
        android:layout_height="200dp"
       >

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你23132" />

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你62" />

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你" />

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你74684" />

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你" />

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你fhdsdg" />

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你45546" />

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你" />

        <TextView
            style="@style/textstyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="我爱你" />

    </com.example.lian0322_1.NewClass>

</LinearLayout>

values/styles中的代码：

  <style name="textstyle">
        <item name="background">#f00</item>
        <item name="layout_margin">10dp</item>
        <item name="layout_width">150dp</item>
        <item name="padding">10dp</item>
        <item name="textColor">#000</item>
        <item name="textSize">20sp</item>
    </style>

public class NewClass extends ViewGroup{

    private final String TAG = getClass().getSimpleName();

    public NewClass(Context context) {
        super(context);
    }

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

    public NewClass(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new MarginLayoutParams(getContext(), attrs);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //1、获得此ViewGroup上级容器为其推荐的宽和高，以及计算模式
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
        int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);

        // 2、如果ViewGroup布局是wrap_content时，根据childView的尺寸，计算容器的宽和高
        int width = 0;//ViewGroup的宽度
        int height = 0;//ViewGroup的高度
        int lineWidth = 0;//childView所占据的当前行总宽度
        int lineHeight = 0;//childView所占据的各行总高度
        int cCount = getChildCount();////childView的数量
        for(int i=0; i<cCount; i++){//遍历每个childView
            View childView = getChildAt(i);
            measureChild(childView, widthMeasureSpec, heightMeasureSpec);// 测量当前child的宽和高
            MarginLayoutParams mlp = (MarginLayoutParams) childView.getLayoutParams();
            int cWidth = childView.getMeasuredWidth() + mlp.leftMargin + mlp.rightMargin;
            int cHeight = childView.getMeasuredHeight() + mlp.topMargin + mlp.bottomMargin;
            if(lineWidth + cWidth > sizeWidth){//如果加入当前childView后超出最大宽度，width取最大高度，累加lineHeight，然后开启新行
                width = Math.max(lineWidth, cWidth);
                height += lineHeight;
                lineWidth = cWidth;
            }else{//如果加入当前childView后小于最大宽度，则累加lineWidthheight lineHeight取最大高度
                lineWidth += cWidth;
                height = Math.max(lineHeight, cHeight);
            }
            if(i == cCount-1){// 如果是最后一个childView，则将当前记录的最大宽度和当前lineWidth做比较
                width = Math.max(lineWidth, cWidth);
                height += lineHeight;
            }
        }

        //3、如果是wrap_content设置为我们计算的值;否则直接设置为父容器计算的值
        setMeasuredDimension(
                (widthMode == MeasureSpec.EXACTLY) ? sizeWidth : width,
                (heightMode == MeasureSpec.EXACTLY) ? sizeHeight : height
        );
    }

    private List<List<View>> allChildViews = new ArrayList<List<View>>();//存储所有的childView，按行记录
    private List<Integer> maxLineHeight = new ArrayList<Integer>();//存储每行的最大高度值

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        allChildViews.clear();
        maxLineHeight.clear();

        int width = getWidth();//每行的最大宽度
        int lineWidth = 0;//每行的即时宽度
        int lineHeight = 0;//每行的即时高度

        List<View> lineChildViews = new ArrayList<View>();//存储每行所有的childView

        int cCount = getChildCount();
        for(int i=0; i<cCount; i++){//遍历所有childView
            View childView = getChildAt(i);
            MarginLayoutParams mlp = (MarginLayoutParams) childView.getLayoutParams();
            int cWidth = childView.getMeasuredWidth();
            int cHeight = childView.getMeasuredHeight();
            if(lineWidth + cWidth + mlp.leftMargin + mlp.rightMargin > width){//如果需要换行
                maxLineHeight.add(lineHeight);// 存储这一行最大高度
                allChildViews.add(lineChildViews);// 将当前行的childView保存，然后开启新的ArrayList保存下一行的childView
                lineChildViews = new ArrayList<View>();
                lineWidth = 0;// 重置行宽
            }else{//如果不需要换行
                lineWidth += cWidth + mlp.leftMargin + mlp.rightMargin;//即时宽度累加
                lineHeight = Math.max(lineHeight,cHeight + mlp.topMargin + mlp.bottomMargin );//即时高度取最大值
                lineChildViews.add(childView);//把当前childView存入这一行的集合
            }
        }
        // 记录最后一行
        maxLineHeight.add(lineHeight);
        allChildViews.add(lineChildViews);

        int left = 0;//左坐标
        int top = 0;//上坐标
        int lineNums = allChildViews.size();// 得到总行数
        for (int i = 0; i < lineNums; i++) {
            lineChildViews = allChildViews.get(i);// 取得每一行的所有的views
            lineHeight = maxLineHeight.get(i);// 取得当前行的最大高度

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

            // 遍历当前行所有的View
            for (int j = 0; j < lineChildViews.size(); j++) {
                View childView = lineChildViews.get(j);//取得childView
                if (childView.getVisibility() == View.GONE) {
                    continue;
                }
                MarginLayoutParams mlp = (MarginLayoutParams) childView.getLayoutParams();
                //计算childView的left,top,right,bottom
                int lc = left + mlp.leftMargin;
                int tc = top + mlp.topMargin;
                int rc = lc + childView.getMeasuredWidth();
                int bc = tc + childView.getMeasuredHeight();

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

                childView.layout(lc, tc, rc, bc);//设置这个childView的位置
                left += childView.getMeasuredWidth() + mlp.rightMargin + mlp.leftMargin;//左坐标累加
            }
            left = 0;//开始新的一行，左坐标重置
            top += lineHeight;//开始新的一行，上坐标累加
        }
    }
    }

MainActivity.java里面不用写任何东西