[自定义控件系列2]--进阶篇：可自动换行的ViewGroup

前言

具体实现

package com.example.king.kingcustomview;

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

import static android.R.attr.width;
import static android.view.View.MeasureSpec.getMode;

/**
* Created by king on 2017/4/9.
* 博客地址：http://blog.csdn.net/jinfulin
*/

public class kingAutoLinearLayout extends ViewGroup {
private int parentWidth;
private int parentHeight;
private int parentautoHeight = 0;

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

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

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

private void init() {
//没有用到的
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
parentWidth = MeasureSpec.getSize(widthMeasureSpec);
parentHeight = MeasureSpec.getSize(heightMeasureSpec);
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
Log.e("king11",parentHeight+"========"+heightMode);
for (int i = 0; i < getChildCount(); i++) {
View childview = getChildAt(i);
// 测量每一个child的宽和高
measureChild(childview, widthMeasureSpec, heightMeasureSpec);
int childHight = childview.getMeasuredHeight();
}
//如果高度是wrap_content设置为我们计算的值
//如果宽度是wrap_content我们设置为match_parent
//否则：直接设为父控件值
setMeasuredDimension(parentWidth,
(heightMode == MeasureSpec.EXACTLY) ? parentHeight: parentautoHeight);
}

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int childLeft = 0;
int childTop = 0;
int index =0;
int maxHeight = 0 ;
for (int i = 0; i < getChildCount(); i++) {
View childview = getChildAt(i);
//如果该控件是gone的，则不作位置摆放
if (childview.getVisibility() == View.GONE) {
continue;
}
// 得到子view的MarginLayoutParams,可以得到的margin等属性
MarginLayoutParams lp = (MarginLayoutParams) childview.getLayoutParams();

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

int left = childLeft + lp.leftMargin;
if (index==0) {
childTop = lp.topMargin;
}

maxHeight = getMaxTop(maxHeight,childHeight+lp.topMargin+lp.bottomMargin);
if (left + childWidth + lp.rightMargin > parentWidth) {
//对left的处理
childLeft = 0;
left = lp.leftMargin;
//对top的处理
index++;
childTop += maxHeight;
}
//获取控件wrapContent时候的高度
parentautoHeight = childTop+maxHeight;

childview.layout(left, childTop, left + childWidth, childTop + childHeight);
childLeft += childWidth + lp.rightMargin + lp.leftMargin;
}
}
//获取该行控件中最高的一个
private int getMaxTop(int oldTop,int newtop){
return Math.max(oldTop,newtop);
}

//要想使用子控件的margin
//必须要实现这个方法，并且返回MarginLayoutParams
@Override
public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
return new MarginLayoutParams(getContext(), attrs);
}
}

<com.example.king.kingcustomview.kingAutoLinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
style="@style/text"
android:text="aaa"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:text="bbb"
style="@style/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="ccc"
android:visibility="gone"
style="@style/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="ccc"
style="@style/text"
android:layout_width="100dp"
android:layout_height="wrap_content"/>
<TextView
android:text="ccc"
style="@style/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="sssssssssssss"
android:layout_marginLeft="10dp"
android:paddingLeft="10dp"
style="@style/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:layout_marginLeft="10dp"
android:paddingLeft="10dp"
android:text="aaa"
style="@style/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="cccccc"
style="@style/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="x"
style="@style/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="xx"
style="@style/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</com.example.king.kingcustomview.kingAutoLinearLayout>