自定义ViewGroup代码

package com.example.customview.customview.keypad;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.GradientDrawable;
import android.graphics.drawable.StateListDrawable;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.example.customview.R;
import com.example.customview.customview.utils.SizeUtils;

public class KeyPadView extends ViewGroup {

    public static final String TAG="KeyPadView";

    //4行
    public static final int DEFAULT_ROW=4;
    //3列
    public static final int DEFAULT_COLUMN=3;
    private int mTextColor;
    private float mTestSize;
    private int mItemNormalBgColor;
    private int mItemPressBgColor;
    private int row=DEFAULT_ROW;
    private int column=DEFAULT_COLUMN;

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

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

    public KeyPadView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        //
        initAttrs(context, attrs);
        //
        setupItem();
    }

    private void setupItem() {
        removeAllViews();
      for(int i=0;i<11;i++) {
          TextView item = new TextView(getContext());
          //内容
          if(i==10){
              //最后一个是删除
              item.setTag(true);
              item.setText("删除");
          }else {
              item.setTag(false);
              item.setText(String.valueOf(i));
          }

          //大小
          item.setTextSize(TypedValue.COMPLEX_UNIT_PX,mTestSize);//将mTestSize转成px格式
          //居中
          item.setGravity(Gravity.CENTER);
          //字体颜色
          item.setTextColor(mTextColor);
          //设置背景
          item.setBackground(providerItemBg());
          item.setOnClickListener(new OnClickListener() {
              @Override
              public void onClick(View v) {

              }
          });
          addView(item);
      }
    }

    //使用java代码编写item的Drawable背景
    private Drawable providerItemBg(){
        //按下去了的background
        GradientDrawable pressDrawable = new GradientDrawable();//GradientDrawable会比ShapeDrawable属性多一些
        pressDrawable.setColor(getResources().getColor(R.color.key_item_press_color));
        pressDrawable.setCornerRadius(SizeUtils.dip2px(5));
        StateListDrawable bg = new StateListDrawable();
        bg.addState(new int[]{android.R.attr.state_pressed},pressDrawable);
        //普通状态的background
        GradientDrawable normalDrawable = new GradientDrawable();
        normalDrawable.setColor(getResources().getColor(R.color.key_item_color));
        normalDrawable.setCornerRadius(SizeUtils.dip2px(5));
        bg.addState(new int[]{},normalDrawable);
        return bg;
    }

    private void initAttrs(Context context, AttributeSet attrs) {
        //attrs获取xml中标记的属性
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.KeyPadView);
        //获取属性
        mTextColor = a.getColor(R.styleable.KeyPadView_numberColor, context.getResources().getColor(R.color.white));
        mTestSize = a.getDimension(R.styleable.KeyPadView_numberSize, 16);
        Log.d(TAG, "mTestSize: --->"+mTestSize);
        mItemNormalBgColor = a.getColor(R.styleable.KeyPadView_itemNormalColor, context.getResources().getColor(R.color.key_item_color));
        mItemPressBgColor = a.getColor(R.styleable.KeyPadView_itemPressColor, context.getResources().getColor(R.color.key_item_press_color));
        a.recycle();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int widthSize=MeasureSpec.getSize(widthMeasureSpec);
        int widthMode=MeasureSpec.getMode(widthMeasureSpec);
        int heightSize=MeasureSpec.getSize(heightMeasureSpec);
        int heightMode=MeasureSpec.getMode(heightMeasureSpec);
        Log.d(TAG, "widthSize: "+widthSize);
        Log.d(TAG, "widthMode: "+widthMode);
        Log.d(TAG, "heightSize: "+heightSize);
        Log.d(TAG, "heightMode: "+heightMode);
        Log.d(TAG, "EXACTLY: "+MeasureSpec.EXACTLY);
        Log.d(TAG, "AT_MOST: "+MeasureSpec.AT_MOST);

        //一行三列，求出列宽，三等分
        int perItemWidth=widthSize/3;
        int perItemHeight=heightSize/4;
        int normalWidthSpec=MeasureSpec.makeMeasureSpec(perItemWidth,MeasureSpec.EXACTLY);
        int deleteWidthSpec=MeasureSpec.makeMeasureSpec(perItemWidth*2,MeasureSpec.EXACTLY);
        int heightSpec=MeasureSpec.makeMeasureSpec(perItemHeight,MeasureSpec.EXACTLY);
        for(int i=0;i<getChildCount();i++){
            View item = getChildAt(i);
            boolean isDelete = (boolean) item.getTag();
            //测量孩子
            Log.d(TAG, "onMeasure: "+MeasureSpec.getSize(normalWidthSpec)+"---->"+MeasureSpec.getSize(heightMeasureSpec));
            item.measure(isDelete ? deleteWidthSpec:normalWidthSpec,heightSpec);
           // measureChild(item,isDelete ? deleteWidthSpec:normalWidthSpec,heightSpec);
        }
        //测量自己
        setMeasuredDimension(widthMeasureSpec,heightMeasureSpec);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int childCount = getChildCount();
        int left=0,top,right,bottom;
        for(int i=0;i<childCount;i++){
            //求出当前元素在第几行第几列
            int rowIndex=i/column;
            int columnIndex=i%column;
            if(columnIndex==0){
                left=0;
            }
            View item = getChildAt(i);
            top=rowIndex*item.getMeasuredHeight();
            right=left+item.getMeasuredWidth();
            bottom=top+item.getMeasuredHeight();
            item.layout(left,top,right,bottom);
            left+=item.getMeasuredWidth();
        }
    }
}

布局代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:YiRan="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical">

<com.example.customview.customview.keypad.KeyPadView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    YiRan:numberSize="70px"
    />

</LinearLayout>

当使用item.measure对子view进行测量的时候显示和大锯哥视频讲解的结果一样是正常的，除了最后一个代表删除的子view，其他每个子view的宽和高都取精确值布满屏幕的1/3和1/4。

但是我记得上一次大锯哥讲解FlowLayout的时候测量子view使用的measureChild方法，我就好奇的将其测量方式改为measureChild

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    int widthSize=MeasureSpec.getSize(widthMeasureSpec);
    int widthMode=MeasureSpec.getMode(widthMeasureSpec);
    int heightSize=MeasureSpec.getSize(heightMeasureSpec);
    int heightMode=MeasureSpec.getMode(heightMeasureSpec);
    Log.d(TAG, "widthSize: "+widthSize);
    Log.d(TAG, "widthMode: "+widthMode);
    Log.d(TAG, "heightSize: "+heightSize);
    Log.d(TAG, "heightMode: "+heightMode);
    Log.d(TAG, "EXACTLY: "+MeasureSpec.EXACTLY);
    Log.d(TAG, "AT_MOST: "+MeasureSpec.AT_MOST);

    //一行三列，求出列宽，三等分
    int perItemWidth=widthSize/3;
    int perItemHeight=heightSize/4;
    int normalWidthSpec=MeasureSpec.makeMeasureSpec(perItemWidth,MeasureSpec.EXACTLY);
    int deleteWidthSpec=MeasureSpec.makeMeasureSpec(perItemWidth*2,MeasureSpec.EXACTLY);
    int heightSpec=MeasureSpec.makeMeasureSpec(perItemHeight,MeasureSpec.EXACTLY);
    for(int i=0;i<getChildCount();i++){
        View item = getChildAt(i);
        boolean isDelete = (boolean) item.getTag();
        //测量孩子
        Log.d(TAG, "onMeasure: "+MeasureSpec.getSize(normalWidthSpec)+"---->"+MeasureSpec.getSize(heightMeasureSpec));
        //item.measure(isDelete ? deleteWidthSpec:normalWidthSpec,heightSpec);
        measureChild(item,isDelete ? deleteWidthSpec:normalWidthSpec,heightSpec);
    }
    //测量自己
    setMeasuredDimension(widthMeasureSpec,heightMeasureSpec);
}

measureChild方法的源码

protected void measureChild(View child, int parentWidthMeasureSpec,
        int parentHeightMeasureSpec) {
    final LayoutParams lp = child.getLayoutParams();

    final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec,
            mPaddingLeft + mPaddingRight, lp.width);
    final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec,
            mPaddingTop + mPaddingBottom, lp.height);

    child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}

看了measureChild方法的源码,发现最后也是调用item的measure方法，想着应该和上面的结果一样才对。可以运行后显示的布局却是这样子

明明已经在测量的时候设置子view大小的时候给他设置了宽高分别为屏幕的1/3和1/4，模式也设置为精确值，但运行后确实这个结果，不太清楚是怎么回事？请各位大佬帮忙看一下