android flowLayout

package com.imooc.view;


import java.util.ArrayList;
import java.util.List;


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


public class FlowLayout extends ViewGroup
{


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


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


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


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
int modeHeight = MeasureSpec.getMode(heightMeasureSpec);


// wrap_content
int width = 0;
int height = 0;


// 記錄每一行的寬度與高度
int lineWidth = 0;
int lineHeight = 0;


// 得到內部元素的個數
int cCount = getChildCount();


for (int i = 0; i < cCount; i++)
{
View child = getChildAt(i);
// 測量子View的寬和高
measureChild(child, widthMeasureSpec, heightMeasureSpec);
// 得到LayoutParams
MarginLayoutParams lp = (MarginLayoutParams) child
.getLayoutParams();


// 子View佔據的寬度
int childWidth = child.getMeasuredWidth() + lp.leftMargin
+ lp.rightMargin;
// 子View佔據的高度
int childHeight = child.getMeasuredHeight() + lp.topMargin
+ lp.bottomMargin;


// 換行
if (lineWidth + childWidth > sizeWidth - getPaddingLeft() - getPaddingRight())
{
// 對比得到最大的寬度
width = Math.max(width, lineWidth);
// 重置lineWidth
lineWidth = childWidth;
// 記錄行高
height += lineHeight;
lineHeight = childHeight;
} else
// 未換行
{
// 疊加行寬
lineWidth += childWidth;
// 得到當前行最大的高度
lineHeight = Math.max(lineHeight, childHeight);
}
// 最後一個控件
if (i == cCount - 1)
{
width = Math.max(lineWidth, width);
height += lineHeight;
}
}


Log.e("TAG", "sizeWidth = " + sizeWidth);
Log.e("TAG", "sizeHeight = " + sizeHeight);


setMeasuredDimension(
//
modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width + getPaddingLeft() + getPaddingRight(),
modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height + getPaddingTop()+ getPaddingBottom()//
);


}


/**
* 存儲所有的View
*/
private List<List<View>> mAllViews = new ArrayList<List<View>>();
/**
* 每一行的高度
*/
private List<Integer> mLineHeight = new ArrayList<Integer>();


@Override
protected void onLayout(boolean changed, int l, int t, int r, int b)
{
mAllViews.clear();
mLineHeight.clear();


// 當前ViewGroup的寬度
int width = getWidth();


int lineWidth = 0;
int lineHeight = 0;


List<View> lineViews = new ArrayList<View>();


int cCount = getChildCount();


for (int i = 0; i < cCount; i++)
{
View child = getChildAt(i);
MarginLayoutParams lp = (MarginLayoutParams) child
.getLayoutParams();


int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();


// 如果需要換行
if (childWidth + lineWidth + lp.leftMargin + lp.rightMargin > width - getPaddingLeft() - getPaddingRight())
{
// 記錄LineHeight
mLineHeight.add(lineHeight);
// 記錄當前行的Views
mAllViews.add(lineViews);


// 重置我們的行寬和行高
lineWidth = 0;
lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
// 重置我們的View集合
lineViews = new ArrayList<View>();
}
lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
lineHeight = Math.max(lineHeight, childHeight + lp.topMargin
+ lp.bottomMargin);
lineViews.add(child);


}// for end
// 處理最後一行
mLineHeight.add(lineHeight);
mAllViews.add(lineViews);


// 設置子View的位置


int left = getPaddingLeft();
int top = getPaddingTop();


// 行數
int lineNum = mAllViews.size();


for (int i = 0; i < lineNum; i++)
{
// 當前行的所有的View
lineViews = mAllViews.get(i);
lineHeight = mLineHeight.get(i);


for (int j = 0; j < lineViews.size(); j++)
{
View child = lineViews.get(j);
// 判斷child的狀態
if (child.getVisibility() == View.GONE)
{
continue;
}


MarginLayoutParams lp = (MarginLayoutParams) child
.getLayoutParams();


int lc = left + lp.leftMargin;
int tc = top + lp.topMargin;
int rc = lc + child.getMeasuredWidth();
int bc = tc + child.getMeasuredHeight();


// 爲子View進行佈局
child.layout(lc, tc, rc, bc);


left += child.getMeasuredWidth() + lp.leftMargin
+ lp.rightMargin;
}
left = getPaddingLeft() ; 
top += lineHeight ; 
}


}


/**
* 與當前ViewGroup對應的LayoutParams
*/
@Override
public LayoutParams generateLayoutParams(AttributeSet attrs)
{
return new MarginLayoutParams(getContext(), attrs);
}


}