CustomImgContainer.java

package com.tekinarslan.material.sample.customgroupview;

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

public class CustomImgContainer extends ViewGroup
{

	private static final String TAG = "CustomImgContainer";

	public CustomImgContainer(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);
	}

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

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

	/**
	 * 计算所有ChildView的宽度和高度 然后根据ChildView的计算结果，设置自己的宽和高
	 */
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
//		Math.min()
		/**
		 * 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);

		Log.e(TAG, (heightMode == MeasureSpec.UNSPECIFIED) + "," + sizeHeight
				+ "," + getLayoutParams().height);

		// 计算出所有的childView的宽和高
		measureChildren(widthMeasureSpec, heightMeasureSpec);
		/**
		 * 记录如果是wrap_content是设置的宽和高
		 */
		int width = 0;
		int height = 0;

		int cCount = getChildCount();

		int cWidth = 0;
		int cHeight = 0;
		MarginLayoutParams cParams = null;

		// 用于计算左边两个childView的高度
		int lHeight = 0;
		// 用于计算右边两个childView的高度，最终高度取二者之间大值
		int rHeight = 0;

		// 用于计算上边两个childView的宽度
		int tWidth = 0;
		// 用于计算下面两个childiew的宽度，最终宽度取二者之间大值
		int bWidth = 0;

		/**
		 * 根据childView计算的出的宽和高，以及设置的margin计算容器的宽和高，主要用于容器是warp_content时
		 */
		for (int i = 0; i < cCount; i++)
		{
			View childView = getChildAt(i);
			cWidth = childView.getMeasuredWidth();
			cHeight = childView.getMeasuredHeight();
			cParams = (MarginLayoutParams) childView.getLayoutParams();

			// 上面两个childView
			if (i == 0 || i == 1)
			{
				tWidth += cWidth + cParams.leftMargin + cParams.rightMargin;
			}

			if (i == 2 || i == 3)
			{
				bWidth += cWidth + cParams.leftMargin + cParams.rightMargin;
			}

			if (i == 0 || i == 2)
			{
				lHeight += cHeight + cParams.topMargin + cParams.bottomMargin;
			}

			if (i == 1 || i == 3)
			{
				rHeight += cHeight + cParams.topMargin + cParams.bottomMargin;
			}

		}
		
		width = Math.max(tWidth, bWidth);
		height = Math.max(lHeight, rHeight);

		/**
		 * 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);
		Log.d("123", "onmeasure..widthMode=" + widthMode + " heigthMode==" + heightMode);
	}

	// abstract method in viewgroup
	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b)
	{
		Log.d("123", "onLayout........");
		int cCount = getChildCount();
		int cWidth = 0;
		int cHeight = 0;
		MarginLayoutParams cParams = null;
		/**
		 * 遍历所有childView根据其宽和高，以及margin进行布局
		 */
		for (int i = 0; i < cCount; i++)
		{
			View childView = getChildAt(i);
			cWidth = childView.getMeasuredWidth();
			cHeight = childView.getMeasuredHeight();
			cParams = (MarginLayoutParams) childView.getLayoutParams();

			int cl = 0, ct = 0, cr = 0, cb = 0;

			switch (i)
			{
			case 0:
				cl = cParams.leftMargin;
				ct = cParams.topMargin+getPaddingTop();
				break;
			case 1:
				cl = getWidth() - cWidth - cParams.leftMargin	- cParams.rightMargin;
				ct = cParams.topMargin+getPaddingTop();
				break;
			case 2:
				cl = cParams.leftMargin;
				ct = getHeight() - cHeight - cParams.bottomMargin;
				break;
			case 3:
				cl = getWidth() - cWidth - cParams.leftMargin
						- cParams.rightMargin;
				ct = getHeight() - cHeight - cParams.bottomMargin;
				break;

			}
			cr = cl + cWidth;
			cb = cHeight + ct;
			childView.layout(cl, ct, cr, cb);
		}

	}

	@Override
	public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs)
	{
		return new MarginLayoutParams(getContext(), attrs);
	}

	@Override
	protected ViewGroup.LayoutParams generateDefaultLayoutParams()
	{
		Log.e(TAG, "generateDefaultLayoutParams");
		return new MarginLayoutParams(LayoutParams.MATCH_PARENT,
				LayoutParams.MATCH_PARENT);
	}

	@Override
	protected ViewGroup.LayoutParams generateLayoutParams(
			ViewGroup.LayoutParams p)
	{
		Log.e(TAG, "generateLayoutParams p");
		return new MarginLayoutParams(p);
	}

}