AndroidAutoLayout源码解析

AndroidAutoLayout源码解析

一 概述

我在很久之前就开始使用这个库了,之前没有深究,后来觉得这个库有一些bug,就没有再使用,现在一些朋友想用这个库,觉得用着不错,所以现在就翻下源码看看,防止以后会出现奇怪的问题.

原项目github:https://github.com/hongyangAndroid/AndroidAutoLayout

使用介绍请看原项目README.md文件,本文章就不再介绍使用上的东西了

二 源码解析

这次分析采用从外到内的分析,从AutoLinearLayout这个类开始

2.1 AutoLinearLayout

/**
 * 百分比线性布局
 * Created by zhy on 15/6/30.
 */
public class AutoLinearLayout extends LinearLayout
{
    //生成一个AutoLayoutHelper对象
    private AutoLayoutHelper mHelper = new AutoLayoutHelper(this);

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

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

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public AutoLinearLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public AutoLinearLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        //编辑模式跳过
        if (!isInEditMode())
            //为子View应用百分比属性
            mHelper.adjustChildren();
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }


    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b)
    {
        super.onLayout(changed, l, t, r, b);
    }


    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs)
    {   //生成自己的LayoutParams
        return new AutoLinearLayout.LayoutParams(getContext(), attrs);
    }


    public static class LayoutParams extends LinearLayout.LayoutParams
            implements AutoLayoutHelper.AutoLayoutParams
    {

        private AutoLayoutInfo mAutoLayoutInfo;

        public LayoutParams(Context c, AttributeSet attrs)
        {
            super(c, attrs);
            //初始化AutoLayoutInfo对象
            mAutoLayoutInfo = AutoLayoutHelper.getAutoLayoutInfo(c, attrs);
        }

        @Override
        public AutoLayoutInfo getAutoLayoutInfo()
        {
            return mAutoLayoutInfo;
        }


        public LayoutParams(int width, int height)
        {
            super(width, height);
        }


        public LayoutParams(ViewGroup.LayoutParams source)
        {
            super(source);
        }

        public LayoutParams(MarginLayoutParams source)
        {
            super(source);
        }

    }

}

从上面可以看出,貌似这个类没有做什么事情,在onMeasure方法的时候和LayoutParams的构造方法中
分别调用AutoLayoutHelper的adjustChildren方法和getAutoLayoutInfo方法,其实我们可以猜测出,adjustChildren就是给子View设置百分比属性的,getAutoLayoutInfo就是拿到百分比信息的关键方法,我们跟进去看

2.2 AutoLayoutHelper

• 构造方法

 public AutoLayoutHelper(ViewGroup host)
    {
        mHost = host;

        if (mAutoLayoutConifg == null)
        {
            initAutoLayoutConfig(host);
        }

    }

    /**
     * @param host
     */
    private void initAutoLayoutConfig(ViewGroup host)
    {
        mAutoLayoutConifg = AutoLayoutConifg.getInstance();
        mAutoLayoutConifg.init(host.getContext());
    }

构造方法里面由构建了一个AutoLayoutConifg 对象,并且只是第一次才会初始化,而且看最后一行,这个AutoLayoutConifg的初始化也只是需要一个Context对象,并不是需要这个ViewGroup的属性什么的,单例的,
并且还需要Context对象,名字上又是Config结尾,那么一定是存储一些配置信息,事实上证明的确是这样的,看代码:

/**
 * 全局的配置
 * 设计稿 像素;屏幕尺寸;使用屏幕大小/除去状态栏高度
 * Created by zhy on 15/11/18.
 */
public class AutoLayoutConifg
{

    private static AutoLayoutConifg sIntance = new AutoLayoutConifg();


    private static final String KEY_DESIGN_WIDTH = "design_width";
    private static final String KEY_DESIGN_HEIGHT = "design_height";
    //屏幕宽高
    private int mScreenWidth;
    private int mScreenHeight;
    //设计稿宽高
    private int mDesignWidth;
    private int mDesignHeight;
    //是否使用整个屏幕的宽高,默认false,除去状态栏
    private boolean useDeviceSize;


    private AutoLayoutConifg()
    {
    }

    /**
     * 是否配置了设计稿尺寸
     */
    public void checkParams()
    {
        if (mDesignHeight <= 0 || mDesignWidth <= 0)
        {
            throw new RuntimeException(
                    "you must set " + KEY_DESIGN_WIDTH + " and " + KEY_DESIGN_HEIGHT + "  in your manifest file.");
        }
    }

    public AutoLayoutConifg useDeviceSize()
    {
        useDeviceSize = true;
        return this;
    }


    public static AutoLayoutConifg getInstance()
    {
        return sIntance;
    }

    //....getset

    public void init(Context context)
    {
        getMetaData(context);
        //获取屏幕宽高
        int[] screenSize = ScreenUtils.getScreenSize(context, useDeviceSize);
        mScreenWidth = screenSize[0];
        mScreenHeight = screenSize[1];
        L.e(" screenWidth =" + mScreenWidth + " ,screenHeight = " + mScreenHeight);
    }
    //获取设计稿大小
    private void getMetaData(Context context)
    {
        PackageManager packageManager = context.getPackageManager();
        ApplicationInfo applicationInfo;
        try
        {
            applicationInfo = packageManager.getApplicationInfo(context
                    .getPackageName(), PackageManager.GET_META_DATA);
            if (applicationInfo != null && applicationInfo.metaData != null)
            {
                mDesignWidth = (int) applicationInfo.metaData.get(KEY_DESIGN_WIDTH);
                mDesignHeight = (int) applicationInfo.metaData.get(KEY_DESIGN_HEIGHT);
            }
        } catch (PackageManager.NameNotFoundException e)
        {
            throw new RuntimeException(
                    "you must set " + KEY_DESIGN_WIDTH + " and " + KEY_DESIGN_HEIGHT + "  in your manifest file.", e);
        }

        L.e(" designWidth =" + mDesignWidth + " , designHeight = " + mDesignHeight);
    }


}

到这里咱们就了解 构造过程了,然后我们来看 完整的代码,注释有说明,

public class AutoLayoutHelper
{
    private final ViewGroup mHost;
    //属性attr,需要进行百分比换算的属性
    private static final int[] LL = new int[]
            { //
                    android.R.attr.textSize,
                    android.R.attr.padding,//
                    android.R.attr.paddingLeft,//
                    android.R.attr.paddingTop,//
                    android.R.attr.paddingRight,//
                    android.R.attr.paddingBottom,//
                    android.R.attr.layout_width,//
                    android.R.attr.layout_height,//
                    android.R.attr.layout_margin,//
                    android.R.attr.layout_marginLeft,//
                    android.R.attr.layout_marginTop,//
                    android.R.attr.layout_marginRight,//
                    android.R.attr.layout_marginBottom,//
                    android.R.attr.maxWidth,//
                    android.R.attr.maxHeight,//
                    android.R.attr.minWidth,//
                    android.R.attr.minHeight,//16843072


            };
    //下标,会在getAutoLayoutInfo用到,根据下标生成 对应的属性
    private static final int INDEX_TEXT_SIZE = 0;
    private static final int INDEX_PADDING = 1;
    private static final int INDEX_PADDING_LEFT = 2;
    private static final int INDEX_PADDING_TOP = 3;
    private static final int INDEX_PADDING_RIGHT = 4;
    private static final int INDEX_PADDING_BOTTOM = 5;
    private static final int INDEX_WIDTH = 6;
    private static final int INDEX_HEIGHT = 7;
    private static final int INDEX_MARGIN = 8;
    private static final int INDEX_MARGIN_LEFT = 9;
    private static final int INDEX_MARGIN_TOP = 10;
    private static final int INDEX_MARGIN_RIGHT = 11;
    private static final int INDEX_MARGIN_BOTTOM = 12;
    private static final int INDEX_MAX_WIDTH = 13;
    private static final int INDEX_MAX_HEIGHT = 14;
    private static final int INDEX_MIN_WIDTH = 15;
    private static final int INDEX_MIN_HEIGHT = 16;


    /**
     * move to other place?
     */
    private static AutoLayoutConifg mAutoLayoutConifg;

    public AutoLayoutHelper(ViewGroup host)
    {
        mHost = host;

        if (mAutoLayoutConifg == null)
        {
            initAutoLayoutConfig(host);
        }

    }

    /**
     * @param host
     */
    private void initAutoLayoutConfig(ViewGroup host)
    {
        mAutoLayoutConifg = AutoLayoutConifg.getInstance();
        mAutoLayoutConifg.init(host.getContext());
    }

    /**
     * 为ViewGroup的子Views应用百分比属性,本质上海市通过 AutoLayoutInfo
     * 这里如果不懂LayoutParams和View以及ViewGroup关系的小伙伴可以去百度一下
     */
    public void adjustChildren()
    {
        AutoLayoutConifg.getInstance().checkParams();

        for (int i = 0, n = mHost.getChildCount(); i < n; i++)
        {
            View view = mHost.getChildAt(i);
            ViewGroup.LayoutParams params = view.getLayoutParams();

            if (params instanceof AutoLayoutParams)
            {
                AutoLayoutInfo info =
                        ((AutoLayoutParams) params).getAutoLayoutInfo();
                if (info != null)
                {
                    info.fillAttrs(view);
                }
            }
        }

    }

    /**
     * 为View生成 AutoLayoutInfo
     * @param context
     * @param attrs
     * @return
     */
    public static AutoLayoutInfo getAutoLayoutInfo(Context context,
                                                   AttributeSet attrs)
    {

        AutoLayoutInfo info = new AutoLayoutInfo();
        //获取app:layout_auto_basewidth="height|padding" 设置
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.AutoLayout_Layout);
        int baseWidth = a.getInt(R.styleable.AutoLayout_Layout_layout_auto_basewidth, 0);
        int baseHeight = a.getInt(R.styleable.AutoLayout_Layout_layout_auto_baseheight, 0);
        a.recycle();
        //获取百分比换算的属性
        TypedArray array = context.obtainStyledAttributes(attrs, LL);

        int n = array.getIndexCount();


        for (int i = 0; i < n; i++)
        {
            int index = array.getIndex(i);
//            String val = array.getString(index);
//            if (!isPxVal(val)) continue;
            //如果不是px 跳过
            if (!DimenUtils.isPxVal(array.peekValue(index))) continue;

            int pxVal = 0;
            try
            {
                pxVal = array.getDimensionPixelOffset(index, 0);
            } catch (Exception ignore)//not dimension
            {
                continue;
            }
            //向AutoLayoutInfo中添加 不同的属性对象
            switch (index)
            {
                case INDEX_TEXT_SIZE:
                    info.addAttr(new TextSizeAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_PADDING:
                    info.addAttr(new PaddingAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_PADDING_LEFT:
                    info.addAttr(new PaddingLeftAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_PADDING_TOP:
                    info.addAttr(new PaddingTopAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_PADDING_RIGHT:
                    info.addAttr(new PaddingRightAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_PADDING_BOTTOM:
                    info.addAttr(new PaddingBottomAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_WIDTH:
                    info.addAttr(new WidthAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_HEIGHT:
                    info.addAttr(new HeightAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MARGIN:
                    info.addAttr(new MarginAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MARGIN_LEFT:
                    info.addAttr(new MarginLeftAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MARGIN_TOP:
                    info.addAttr(new MarginTopAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MARGIN_RIGHT:
                    info.addAttr(new MarginRightAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MARGIN_BOTTOM:
                    info.addAttr(new MarginBottomAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MAX_WIDTH:
                    info.addAttr(new MaxWidthAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MAX_HEIGHT:
                    info.addAttr(new MaxHeightAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MIN_WIDTH:
                    info.addAttr(new MinWidthAttr(pxVal, baseWidth, baseHeight));
                    break;
                case INDEX_MIN_HEIGHT:
                    info.addAttr(new MinHeightAttr(pxVal, baseWidth, baseHeight));
                    break;
            }
        }
        array.recycle();
        L.e(" getAutoLayoutInfo " + info.toString());
        return info;
    }

    public interface AutoLayoutParams
    {
        AutoLayoutInfo getAutoLayoutInfo();
    }

简单叙述一下,这个类就是帮助LayoutParams生成AutoLayoutInfo的,其实说白了就是拦截一些需要进行百分比换算的属性,然后存储到AutoLayoutInfo中,adjustChildren方法就是遍历子View,然后拿到子View的LayoutParams,再拿到子View的AutoLayoutInfo,AutoLayoutInfo里面维护者一个该View的百分比属性列表,然后进行属性遍历,应用

/**
 * 其实这个类基本就是 存储的属性集合
 */
public class AutoLayoutInfo {
    /**
     * 存储属性
     */
    private List<AutoAttr> autoAttrs = new ArrayList<>();

    public void addAttr(AutoAttr autoAttr) {
        autoAttrs.add(autoAttr);
    }

    /**
     * 应用属性(调用属性自己的apply方法)
     * @param view
     */
    public void fillAttrs(View view) {
        for (AutoAttr autoAttr : autoAttrs) {
            autoAttr.apply(view);
        }
    }

    /**
     * 获取一个View的百分比属性
     * 这里采用的是与运算判断 属性值是否存在
     * {@link com.zhy.autolayout.utils.AutoUtils#auto(View, int, int)}
     * @param view
     * @param attrs
     * @param base
     * @return
     */
    public static AutoLayoutInfo getAttrFromView(View view, int attrs, int base) {
        ViewGroup.LayoutParams params = view.getLayoutParams();
        if (params == null) return null;
        AutoLayoutInfo autoLayoutInfo = new AutoLayoutInfo();

        // width & height
        if ((attrs & Attrs.WIDTH) != 0 && params.width > 0) {
            autoLayoutInfo.addAttr(WidthAttr.generate(params.width, base));
        }

        if ((attrs & Attrs.HEIGHT) != 0 && params.height > 0) {
            autoLayoutInfo.addAttr(HeightAttr.generate(params.height, base));
        }

        //margin
        if (params instanceof ViewGroup.MarginLayoutParams) {
            if ((attrs & Attrs.MARGIN) != 0) {
                autoLayoutInfo.addAttr(MarginLeftAttr.generate(((ViewGroup.MarginLayoutParams) params).leftMargin, base));
                autoLayoutInfo.addAttr(MarginTopAttr.generate(((ViewGroup.MarginLayoutParams) params).topMargin, base));
                autoLayoutInfo.addAttr(MarginRightAttr.generate(((ViewGroup.MarginLayoutParams) params).rightMargin, base));
                autoLayoutInfo.addAttr(MarginBottomAttr.generate(((ViewGroup.MarginLayoutParams) params).bottomMargin, base));
            }
            if ((attrs & Attrs.MARGIN_LEFT) != 0) {
                autoLayoutInfo.addAttr(MarginLeftAttr.generate(((ViewGroup.MarginLayoutParams) params).leftMargin, base));
            }
            if ((attrs & Attrs.MARGIN_TOP) != 0) {
                autoLayoutInfo.addAttr(MarginTopAttr.generate(((ViewGroup.MarginLayoutParams) params).topMargin, base));
            }
            if ((attrs & Attrs.MARGIN_RIGHT) != 0) {
                autoLayoutInfo.addAttr(MarginRightAttr.generate(((ViewGroup.MarginLayoutParams) params).rightMargin, base));
            }
            if ((attrs & Attrs.MARGIN_BOTTOM) != 0) {
                autoLayoutInfo.addAttr(MarginBottomAttr.generate(((ViewGroup.MarginLayoutParams) params).bottomMargin, base));
            }
        }

        //padding
        if ((attrs & Attrs.PADDING) != 0) {
            autoLayoutInfo.addAttr(PaddingLeftAttr.generate(view.getPaddingLeft(), base));
            autoLayoutInfo.addAttr(PaddingTopAttr.generate(view.getPaddingTop(), base));
            autoLayoutInfo.addAttr(PaddingRightAttr.generate(view.getPaddingRight(), base));
            autoLayoutInfo.addAttr(PaddingBottomAttr.generate(view.getPaddingBottom(), base));
        }
        if ((attrs & Attrs.PADDING_LEFT) != 0) {
            autoLayoutInfo.addAttr(MarginLeftAttr.generate(view.getPaddingLeft(), base));
        }
        if ((attrs & Attrs.PADDING_TOP) != 0) {
            autoLayoutInfo.addAttr(MarginTopAttr.generate(view.getPaddingTop(), base));
        }
        if ((attrs & Attrs.PADDING_RIGHT) != 0) {
            autoLayoutInfo.addAttr(MarginRightAttr.generate(view.getPaddingRight(), base));
        }
        if ((attrs & Attrs.PADDING_BOTTOM) != 0) {
            autoLayoutInfo.addAttr(MarginBottomAttr.generate(view.getPaddingBottom(), base));
        }

        //minWidth ,maxWidth , minHeight , maxHeight
        if ((attrs & Attrs.MIN_WIDTH) != 0) {
            autoLayoutInfo.addAttr(MinWidthAttr.generate(MinWidthAttr.getMinWidth(view), base));
        }
        if ((attrs & Attrs.MAX_WIDTH) != 0) {
            autoLayoutInfo.addAttr(MaxWidthAttr.generate(MaxWidthAttr.getMaxWidth(view), base));
        }
        if ((attrs & Attrs.MIN_HEIGHT) != 0) {
            autoLayoutInfo.addAttr(MinHeightAttr.generate(MinHeightAttr.getMinHeight(view), base));
        }
        if ((attrs & Attrs.MAX_HEIGHT) != 0) {
            autoLayoutInfo.addAttr(MaxHeightAttr.generate(MaxHeightAttr.getMaxHeight(view), base));
        }

        //textsize

        if (view instanceof TextView) {
            if ((attrs & Attrs.TEXTSIZE) != 0) {
                autoLayoutInfo.addAttr(TextSizeAttr.generate((int) ((TextView) view).getTextSize(), base));
            }
        }
        return autoLayoutInfo;
    }


    @Override
    public String toString() {
        return "AutoLayoutInfo{" +
                "autoAttrs=" + autoAttrs +
                '}';
    }
}

2.3 属性封装

有时候不得不说大神就是大神,属性对象的抽取,让扩展变得十分容易

属性对象有个超类 AutoAttr.java

/**
 * 属性抽象类,由具体的属性实现,如何设置属性值,其实是px->百分比之后的px
 *
 * Created by zhy on 15/12/4.
 */
public abstract class AutoAttr
{
    public static final int BASE_WIDTH = 1;
    public static final int BASE_HEIGHT = 2;
    public static final int BASE_DEFAULT = 3;

    protected int pxVal;
    protected int baseWidth;
    protected int baseHeight;


    public AutoAttr(int pxVal, int baseWidth, int baseHeight)
    {
        this.pxVal = pxVal;
        this.baseWidth = baseWidth;
        this.baseHeight = baseHeight;
    }

    /**
     * 这里只是根据 baseHeight/baseWidth/userDefault 得到转换后的百分比px值
     * @param view
     */
    public void apply(View view)
    {

        boolean log = view.getTag() != null && view.getTag().toString().equals("auto");

        if (log)
        {
            L.e(" pxVal = " + pxVal + " ," + this.getClass().getSimpleName());
        }
        int val;
        if (useDefault())
        {
            val = defaultBaseWidth() ? getPercentWidthSize() : getPercentHeightSize();
            if (log)
            {
                L.e(" useDefault val= " + val);
            }
        } else if (baseWidth())
        {
            val = getPercentWidthSize();
            if (log)
            {
                L.e(" baseWidth val= " + val);
            }
        } else
        {
            val = getPercentHeightSize();
            if (log)
            {
                L.e(" baseHeight val= " + val);
            }
        }

        if (val > 0)
            val = Math.max(val, 1);//for very thin divider

        execute(view, val);
    }

    protected int getPercentWidthSize()
    {
        return AutoUtils.getPercentWidthSizeBigger(pxVal);
    }

    protected int getPercentHeightSize()
    {
        return AutoUtils.getPercentHeightSizeBigger(pxVal);
    }

    /**
     * 是否baseWidth
     * @return
     */
    protected boolean baseWidth()
    {
        return contains(baseWidth, attrVal());
    }

    /**
     * 是否设置了以某个方向(width/height)像素作为参考
     * @return
     */
    protected boolean useDefault()
    {
        return !contains(baseHeight, attrVal()) && !contains(baseWidth, attrVal());
    }

    protected boolean contains(int baseVal, int flag)
    {
        return (baseVal & flag) != 0;
    }
    /**
     * 对应的属性类别
     * {@link Attrs}
     */
    protected abstract int attrVal();

    protected abstract boolean defaultBaseWidth();

    /**
     * 由具体的属性去设置 如何 设置值
     * @param view
     * @param val
     */
    protected abstract void execute(View view, int val);


    @Override
    public String toString()
    {
        return "AutoAttr{" +
                "pxVal=" + pxVal +
                ", baseWidth=" + baseWidth() +
                ", defaultBaseWidth=" + defaultBaseWidth() +
                '}';
    }
}

注释已经很清楚了

我们看一个常用属性的具体实现

/**
 * Created by zhy on 15/12/5.
 */
public class HeightAttr extends AutoAttr
{
    public HeightAttr(int pxVal, int baseWidth, int baseHeight)
    {
        super(pxVal, baseWidth, baseHeight);
    }

    @Override
    protected int attrVal()
    {
        return Attrs.HEIGHT;
    }

    @Override
    protected boolean defaultBaseWidth()
    {
        return false;
    }

    @Override
    protected void execute(View view, int val)
    {
        ViewGroup.LayoutParams lp = view.getLayoutParams();
        lp.height = val;
    }

    public static HeightAttr generate(int val, int baseFlag)
    {
        HeightAttr heightAttr = null;
        switch (baseFlag)
        {
            case AutoAttr.BASE_WIDTH:
                heightAttr = new HeightAttr(val, Attrs.HEIGHT, 0);
                break;
            case AutoAttr.BASE_HEIGHT:
                heightAttr = new HeightAttr(val, 0, Attrs.HEIGHT);
                break;
            case AutoAttr.BASE_DEFAULT:
                heightAttr = new HeightAttr(val, 0, 0);
                break;
        }
        return heightAttr;
    }


}

看起来是不是十分的简单,到这里我们的分析就到一段落了,下面我们试着来扩展一个ViewGroup

三 扩展

3.1 AutoConstraintLayout

package com.zhy.autolayout;

import android.content.Context;
import android.support.constraint.ConstraintLayout;
import android.util.AttributeSet;
import android.view.ViewGroup;

import com.zhy.autolayout.utils.AutoLayoutHelper;

/**
 * Created by Administrator on 2017/10/29.
 */

public class AutoConstraintLayout extends ConstraintLayout {

    AutoLayoutHelper helper=new AutoLayoutHelper(this);

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

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

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

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        if(!isInEditMode()){
            helper.adjustChildren();
        }
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }


    public static class LayoutParams extends ConstraintLayout.LayoutParams
            implements AutoLayoutHelper.AutoLayoutParams{

        AutoLayoutInfo mInfo;

        public LayoutParams(ConstraintLayout.LayoutParams source) {
            super(source);
        }

        public LayoutParams(Context c, AttributeSet attrs) {
            super(c, attrs);
            mInfo=AutoLayoutHelper.getAutoLayoutInfo(c,attrs);
        }

        public LayoutParams(int width, int height) {
            super(width, height);
        }

        public LayoutParams(ViewGroup.LayoutParams source) {
            super(source);
        }

        @Override
        public AutoLayoutInfo getAutoLayoutInfo() {
            return mInfo;
        }
    }
}

然后在AutoLayoutActivity加入我们的拦截就好了

/**
 * Created by zhy on 15/11/19.
 */
public class AutoLayoutActivity extends AppCompatActivity
{
    private static final String LAYOUT_LINEARLAYOUT = "LinearLayout";
    private static final String LAYOUT_FRAMELAYOUT = "FrameLayout";
    private static final String LAYOUT_RELATIVELAYOUT = "RelativeLayout";
    //不在android.widget包下的需要拦截传入包名+类名
    private static final String LAYOUT_CONSTRAINTLAYOUT = "android.support.constraint.ConstraintLayout";


    @Override
    public View onCreateView(String name, Context context, AttributeSet attrs)
    {
        View view = null;
        if (name.equals(LAYOUT_FRAMELAYOUT))
        {
            view = new AutoFrameLayout(context, attrs);
        }

        if (name.equals(LAYOUT_LINEARLAYOUT))
        {
            view = new AutoLinearLayout(context, attrs);
        }

        if (name.equals(LAYOUT_RELATIVELAYOUT))
        {
            view = new AutoRelativeLayout(context, attrs);
        }
        //咱们添加的
        if (name.equals(LAYOUT_CONSTRAINTLAYOUT))
        {
            view = new AutoConstraintLayout(context, attrs);
        }

        if (view != null) return view;

        return super.onCreateView(name, context, attrs);
    }
}

ok.到这里就结束了,对于属性的扩展暂时没有想到什么例子,有时间可以去他的github逛逛,bug还是挺多的,而且这个库也不再维护了,所以,使用需谨慎,不过我既然选择了,含着泪也要坚持下去=.=