Android 自定义自动换行控件

声明：本文在http://blog.sina.com.cn/s/blog_73e890f40101docf.html基础上修改而成

<com.pm.views.PredicateLayout

android:id="@+id/tag"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal"

android:paddingLeft="10dp"

android:paddingBottom="5dp"

>

</com.pm.views.PredicateLayout>

与原文不一样的地方主要在于onmeasure函数，干掉了不必要的mx，my,然后增加对padding的支持

package com.pm.views;

import java.util.Hashtable;

import android.content.Context;

import android.util.AttributeSet;

import android.util.Log;

import android.view.View;

import android.widget.LinearLayout;

public class PredicateLayout extends LinearLayout {

int mLeft, mRight, mTop, mBottom;

Hashtable<View, Position> map = new Hashtable<View, Position>();

/**

* 每个view上下的间距

*/

private final int dividerLine = 5;

/**

* 每个view左右的间距

*/

private final int dividerCol = 8;

public PredicateLayout(Context context) {

super(context);

}

public PredicateLayout(Context context, int horizontalSpacing, int verticalSpacing) {

super(context);

}

public PredicateLayout(Context context, AttributeSet attrs) {

super(context, attrs);

}

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

int mWidth = MeasureSpec.getSize(widthMeasureSpec);

int mCount = getChildCount();

// int mX = 0;

// int mY = 0;

mLeft = 0;

mRight = 0;

mTop = 5;

mBottom = 0;

int j = 0;

for (int i = 0; i < mCount; i++) {

final View child = getChildAt(i);

child.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);

// 此处增加onlayout中的换行判断，用于计算所需的高度

int childw = child.getMeasuredWidth();

int childh = child.getMeasuredHeight();

mRight += childw; //将每次子控件宽度进行统计叠加，如果大于设定的宽度则需要换行，高度即Top坐标也需重新设置

Position position = new Position();

mLeft = getPosition(i - j, i);

mRight = mLeft + child.getMeasuredWidth();

if (mRight >= mWidth) {

// mX = childw;

// mY += childh;

j = i;

mLeft = getPaddingLeft();

mRight = mLeft + child.getMeasuredWidth();

mTop += childh + dividerLine;

//PS：如果发现高度还是有问题就得自己再细调了

}

mBottom = mTop + child.getMeasuredHeight();

// mY = mTop; //每次的高度必须记录 否则控件会叠加到一起

// mX = mRight;

position.left = mLeft;

position.top = mTop;

position.right = mRight;

position.bottom = mBottom;

map.put(child, position);

}

setMeasuredDimension(mWidth, mBottom+getPaddingBottom());

}

@Override

protected LayoutParams generateDefaultLayoutParams() {

return new LayoutParams(1, 1); // default of 1px spacing

}

@Override

protected void onLayout(boolean changed, int l, int t, int r, int b) {

// TODO Auto-generated method stub

int count = getChildCount();

for (int i = 0; i < count; i++) {

View child = getChildAt(i);

Position pos = map.get(child);

if (pos != null) {

child.layout(pos.left, pos.top, pos.right, pos.bottom);

} else {

Log.i("MyLayout", "error");

}

}

}

private class Position {

int left, top, right, bottom;

}

public int getPosition(int IndexInRow, int childIndex) {

if (IndexInRow > 0) {

return getPosition(IndexInRow - 1, childIndex - 1)

+ getChildAt(childIndex - 1).getMeasuredWidth() + dividerCol;

}

return getPaddingLeft();

}

}