自定义VIewGroup 实现云标签

自定义属性，在res/values下新建attrs文件

<declare-styleable name="TagsLayout">
    <attr name="tagVerticalSpace" format="dimension" />
    <attr name="tagHorizontalSpace" format="dimension" />
declare-styleable>

这是自定义的ViewGroup类

import android.content.Context;
import android.content.res.TypedArray;
import android.location.Location;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;

public class MyViewGroup extends ViewGroup{

    private int childHorizontalSpace;
    private int childVerticalSpace;

    public MyViewGroup(Context context) {
        super(context,null);
    }

    public MyViewGroup(Context context, AttributeSet attrs) {
        super(context, attrs,0);
        TypedArray attrArray = context.obtainStyledAttributes(attrs, R.styleable.TagsLayout);
        if (attrArray != null) {
            childHorizontalSpace = attrArray.getDimensionPixelSize(R.styleable.TagsLayout_tagHorizontalSpace, 0);
            childVerticalSpace = attrArray.getDimensionPixelSize(R.styleable.TagsLayout_tagVerticalSpace, 0);
            attrArray.recycle();
        }
    }

    public MyViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    protected LayoutParams generateDefaultLayoutParams() {
        return new ViewGroup.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    }
    @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);
        // 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 count = getChildCount();
        int left = getPaddingLeft();
        int top = getPaddingTop();
        // 遍历每个子元素
        for (int i = 0; i < count; i++) {
            View child = getChildAt(i);
            if (child.getVisibility() == GONE)
                continue;
            // 测量每一个child的宽和高
            measureChild(child, widthMeasureSpec, heightMeasureSpec);
            // 得到child的lp
            ViewGroup.LayoutParams lp = child.getLayoutParams();
            // 当前子空间实际占据的宽度
            int childWidth = child.getMeasuredWidth() + childHorizontalSpace;
            // 当前子空间实际占据的高度
            int childHeight = child.getMeasuredHeight() + childVerticalSpace;

            if (lp != null && lp instanceof MarginLayoutParams) {
                MarginLayoutParams params = (MarginLayoutParams) lp;
                childWidth += params.leftMargin + params.rightMargin;
                childHeight += params.topMargin + params.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 - getPaddingLeft() - getPaddingRight()) {
                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;
                child.setTag(new Location(left, top + height, childWidth + left - childHorizontalSpace, height + child.getMeasuredHeight() + top));
            } else {// 否则累加值lineWidth,lineHeight取最大高度
                child.setTag(new Location(lineWidth + left, top + height, lineWidth + childWidth - childHorizontalSpace + left, height + child.getMeasuredHeight() + top));
                lineWidth += childWidth;
                lineHeight = Math.max(lineHeight, childHeight);
            }
        }
        width = Math.max(width, lineWidth) + getPaddingLeft() + getPaddingRight();
        height += lineHeight;
        sizeHeight += getPaddingTop() + getPaddingBottom();
        height += getPaddingTop() + getPaddingBottom();
        setMeasuredDimension((modeWidth == MeasureSpec.EXACTLY) ? sizeWidth : width, (modeHeight == MeasureSpec.EXACTLY) ? sizeHeight : height);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int count = getChildCount();
        for (int i = 0; i < count; i++) {
            View child = getChildAt(i);
            if (child.getVisibility() == GONE)
                continue;
            Location location = (Location) child.getTag();
            child.layout(location.left, location.top, location.right, location.bottom);
        }
    }

    public class Location{
        public Location(int left, int top, int right, int bottom) {
            this.left = left;
            this.top = top;
            this.right = right;
            this.bottom = bottom;
        }

        public int left;
        public int top;
        public int right;
        public int bottom;

    }
}

在xml中引用

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:lee="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

   <com.example.hasee.myday.MyViewGroup
       android:id="@+id/groupview"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:layout_margin="10dp"
       lee:tagHorizontalSpace="10dp"
       lee:tagVerticalSpace="20dp">
   com.example.hasee.myday.MyViewGroup>
LinearLayout>

在代码中使用

 MyViewGroup  viewGroup = (MyViewGroup) findViewById(R.id.groupview);
 ViewGroup.MarginLayoutParams lp = new ViewGroup.MarginLayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
 String[] string={"午餐","快手菜大的萨达","饮品","甜品","家常菜","晚餐","早餐","黄培"};
/* String[] string={"从我写代码那天起，我就没有打算写代码","从我写代码那天起","我就没有打算写代码","没打算","写代码"};*/
 for (int i = 0; i < string.length; i++) {
     TextView textView = new TextView(this);
     textView.setText(string[i]);
     textView.setTextColor(Color.BLACK);
     textView.setPadding(20,20,20,20);
     textView.setBackgroundResource(R.drawable.aaa);
     viewGroup.addView(textView,lp);
 }