Android可换行的RadioGroup,有时候需要换行显示的单选列表，当然可以有多种实现方式，比如recycleview或者listview实现，本文采用的是RadioGroup+rediobutton方式实现。
一、首先自定义view
public class WrapRadioGroup extends RadioGroup {
private static final String TAG = "RadioGroupEx";
public WrapRadioGroup(Context context) {
super(context);
}
public WrapRadioGroup(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
//调用ViewGroup的方法，测量子view
measureChildren(widthMeasureSpec, heightMeasureSpec);
//最大的宽
int maxWidth = 0;
//累计的高
int totalHeight = 0;
//当前这一行的累计行宽
int lineWidth = 0;
//当前这行的最大行高
int maxLineHeight = 0;
//用于记录换行前的行宽和行高
int oldHeight;
int oldWidth;
int count = getChildCount();
//假设 widthMode和heightMode都是AT_MOST
for (int i = 0; i < count; i++) {
View child = getChildAt(i);
MarginLayoutParams params = (MarginLayoutParams) child.getLayoutParams();
//得到这一行的最高
oldHeight = maxLineHeight;
//当前最大宽度
oldWidth = maxWidth;
int deltaX = child.getMeasuredWidth() + params.leftMargin + params.rightMargin;
if (lineWidth + deltaX + getPaddingLeft() + getPaddingRight() > widthSize) {//如果折行,height增加
//和目前最大的宽度比较,得到最宽。不能加上当前的child的宽,所以用的是oldWidth
maxWidth = Math.max(lineWidth, oldWidth);
//重置宽度
lineWidth = deltaX;
//累加高度
totalHeight += oldHeight;
//重置行高,当前这个View，属于下一行，因此当前最大行高为这个child的高度加上margin
maxLineHeight = child.getMeasuredHeight() + params.topMargin + params.bottomMargin;
// Log.v(TAG, "maxHeight:" + totalHeight + "---" + "maxWidth:" + maxWidth);
} else {
//不换行，累加宽度
lineWidth += deltaX;
//不换行，计算行最高
int deltaY = child.getMeasuredHeight() + params.topMargin + params.bottomMargin;
maxLineHeight = Math.max(maxLineHeight, deltaY);
}
if (i == count - 1) {
//前面没有加上下一行的搞，如果是最后一行，还要再叠加上最后一行的最高的值
totalHeight += maxLineHeight;
//计算最后一行和前面的最宽的一行比较
maxWidth = Math.max(lineWidth, oldWidth);
}
}
//加上当前容器的padding值
maxWidth += getPaddingLeft() + getPaddingRight();
totalHeight += getPaddingTop() + getPaddingBottom();
setMeasuredDimension(widthMode == MeasureSpec.EXACTLY ? widthSize : maxWidth,
heightMode == MeasureSpec.EXACTLY ? heightSize : totalHeight);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int count = getChildCount();
//pre为前面所有的child的相加后的位置
int preLeft = getPaddingLeft();
int preTop = getPaddingTop();
//记录每一行的最高值
int maxHeight = 0;
for (int i = 0; i < count; i++) {
View child = getChildAt(i);
MarginLayoutParams params = (MarginLayoutParams) child.getLayoutParams();
//r-l为当前容器的宽度。如果子view的累积宽度大于容器宽度，就换行。
if (preLeft + params.leftMargin + child.getMeasuredWidth() + params.rightMargin + getPaddingRight() > (r - l)) {
//重置
preLeft = getPaddingLeft();
//要选择child的height最大的作为设置
preTop = preTop + maxHeight;
maxHeight = getChildAt(i).getMeasuredHeight() + params.topMargin + params.bottomMargin;
} else { //不换行,计算最大高度
maxHeight = Math.max(maxHeight, child.getMeasuredHeight() + params.topMargin + params.bottomMargin);
}
//left坐标
int left = preLeft + params.leftMargin;
//top坐标
int top = preTop + params.topMargin;
int right = left + child.getMeasuredWidth();
int bottom = top + child.getMeasuredHeight();
//为子view布局
child.layout(left, top, right, bottom);
//计算布局结束后，preLeft的值
preLeft += params.leftMargin + child.getMeasuredWidth() + params.rightMargin;
}
}
}
二、布局直接引用
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<csu.xiaoya.robotApp.ui.view.WrapRadioGroup
android:id="@+id/rg_bls"
android:layout_width="438dp"
android:layout_height="179dp"
android:layout_below="@id/monitor_remd"
android:layout_alignParentRight="true"
android:layout_marginTop="@dimen/dp_15"
android:layout_marginRight="@dimen/dp_24"
android:orientation="horizontal"
android:padding="1dp"
app:maxWidth="300dp">
<RadioButton
android:id="@+id/rb_date_day"
android:layout_width="@dimen/dp_84"
android:layout_height="@dimen/dimen_48"
android:background="@drawable/bls_am_2h_sg"
android:button="@null"
android:checked="true"
android:layout_marginLeft="@dimen/dp_10"
android:gravity="center"
android:text="随机血糖"
android:textColor="@color/white"
android:textSize="@dimen/sp_10" />
<RadioButton
android:id="@+id/rb_date_week"
android:layout_width="@dimen/dp_84"
android:layout_height="@dimen/dimen_48"
android:layout_marginLeft="@dimen/dp_10"
android:background="@drawable/bls_am_2h_sg"
android:button="@null"
android:gravity="center"
android:text="空腹血糖"
android:textColor="@color/white"
android:textSize="@dimen/sp_10" />
<RadioButton
android:layout_width="@dimen/dp_84"
android:layout_height="@dimen/dimen_48"
android:layout_marginLeft="@dimen/dp_10"
android:background="@drawable/bls_am_2h_sg"
android:button="@null"
android:gravity="center"
android:text="早餐后2小时"
android:textColor="@color/white"
android:textSize="@dimen/sp_10" />
<RadioButton
android:layout_width="@dimen/dp_84"
android:layout_height="@dimen/dimen_48"
android:layout_marginLeft="@dimen/dp_10"
android:background="@drawable/bls_am_2h_sg"
android:button="@null"
android:gravity="center"
android:text="早餐后2小时"
android:textColor="@color/white"
android:textSize="@dimen/sp_10" />
<RadioButton
android:layout_width="@dimen/dp_84"
android:layout_height="@dimen/dimen_48"
android:layout_marginLeft="@dimen/dp_10"
android:layout_marginTop="@dimen/dp_10"
android:background="@drawable/bls_am_2h_sg"
android:button="@null"
android:gravity="center"
android:text="早餐后2小时"
android:textColor="@color/white"
android:textSize="@dimen/sp_10" />
</csu.xiaoya.robotApp.ui.view.WrapRadioGroup>
</LinearLayout>三、背景样式bls_am_2h_sg
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:width="84dp" android:height="48dp" android:state_checked="false">
<shape android:shape="rectangle">
<solid android:color="#ff27b074" />
<corners android:bottomLeftRadius="5dp" android:bottomRightRadius="5dp" android:topLeftRadius="5dp" android:topRightRadius="5dp" />
</shape>
</item>
<item android:width="88dp" android:height="50dp" android:state_checked="true">
<shape android:shape="rectangle">
<solid android:color="#ff27b074" />
<corners android:bottomLeftRadius="5dp" android:bottomRightRadius="5dp" android:topLeftRadius="5dp" android:topRightRadius="5dp" />
</shape>
</item>
</selector>
