自定义ViewGroup

步骤：

1,继承viewgroup
2,重写onMeasure

@Override//测量
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width = getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        height = getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec);
        measureChildren(width, height);
    }

3,重写onLayout

 @Override//布局（changed横竖屏切换）,把Children画到哪里((l,t)左上角，(r,b)右下角)
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
//        int left = 0;
//        int top = 0;
//        //得到所有的子view
//        for (int i = 0; i < getChildCount(); i++) {
//            View child = getChildAt(i);
//            child.layout(left, top, left + child.getMeasuredWidth(), top + child.getMeasuredHeight());
//        }
        View child1=getChildAt(0);
        View child2=getChildAt(1);
        View child3=getChildAt(2);
        View child4=getChildAt(3);
        if (child1!=null){
            child1.layout(0,0,child1.getMeasuredWidth(),child1.getMeasuredHeight());
        }
        if (child2!=null){
            child2.layout(r-child2.getMeasuredWidth(),0,r,child2.getMeasuredHeight());
        }
        if (child3!=null){
            child3.layout(0,b-child3.getMeasuredHeight(),child3.getMeasuredWidth(),b);
        }
        if (child4!=null){
            child4.layout(r-child4.getMeasuredWidth(),b-child4.getMeasuredHeight(),r,b);
        }
    }

效果图：

代码：

layout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">
   <com.example.administrator.mywidgetmode.ViewGroup.MyViewGroup
       android:layout_width="match_parent"
       android:layout_height="match_parent">
       <Button
           android:text="按钮1"
           android:layout_width="100dp"
           android:layout_height="100dp" />
       <Button
           android:text="按钮2"
           android:layout_width="80dp"
           android:layout_height="80dp" />
       <Button
           android:text="按钮3"
           android:layout_width="60dp"
           android:layout_height="60dp" />
       <Button
           android:text="按钮4"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content" />
   </com.example.administrator.mywidgetmode.ViewGroup.MyViewGroup>
</LinearLayout>![这里写图片描述](https://img-blog.youkuaiyun.com/20150919114033914)

MyViewGroup:

package com.example.administrator.mywidgetmode.ViewGroup;

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

/**
 * Created by Administrator on 2015/9/19.
 */
public class MyViewGroup extends ViewGroup {
    private int width;
    private int height;

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

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

    @Override//测量
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width = getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        height = getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec);
        measureChildren(width, height);
    }

    @Override//布局（changed横竖屏切换）,把Children画到哪里((l,t)左上角，(r,b)右下角)
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
//        int left = 0;
//        int top = 0;
//        //得到所有的子view
//        for (int i = 0; i < getChildCount(); i++) {
//            View child = getChildAt(i);
//            child.layout(left, top, left + child.getMeasuredWidth(), top + child.getMeasuredHeight());
//        }
        View child1=getChildAt(0);
        View child2=getChildAt(1);
        View child3=getChildAt(2);
        View child4=getChildAt(3);
        if (child1!=null){
            child1.layout(0,0,child1.getMeasuredWidth(),child1.getMeasuredHeight());
        }
        if (child2!=null){
            child2.layout(r-child2.getMeasuredWidth(),0,r,child2.getMeasuredHeight());
        }
        if (child3!=null){
            child3.layout(0,b-child3.getMeasuredHeight(),child3.getMeasuredWidth(),b);
        }
        if (child4!=null){
            child4.layout(r-child4.getMeasuredWidth(),b-child4.getMeasuredHeight(),r,b);
        }
    }
}

MyViewGroupActivity:

package com.example.administrator.mywidgetmode.ViewGroup;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.example.administrator.mywidgetmode.R;

/**
 * Created by Administrator on 2015/9/19.
 */
public class MyViewGroupActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_viewgroup);
    }
}