由于项目下一个版本添加了商品选择需求，需要添加一组单选标签流，考虑标签选项不是很多，最好选择用自定义RadioGroup实现。
重点在于onMeasure方法中计算每一行的宽带进行分行，onLayout方法中设置每个RadioButton的位置。
先看效果图
Paste_Image.png
CustomRadioGroup.java代码（注释非常详细，不在做详解）
package com.dengxiao.customradiogrouptag;
import android.content.Context;
import android.util.AttributeSet;
import android.util.SparseArray;
import android.view.View;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Dengxiao on 2016/12/2.
*/
public class CustomRadioGroup extends RadioGroup {
private List rowViews;//存放每行radioBotton的集合
private int horizontalSpacing =20;//默认水平间距
private int verticalSpacing = 10;//默认垂直间距
private Context mContext;
private OnclickListener listener;
public void setListener(OnclickListener listener) {
this.listener = listener;
}
public CustomRadioGroup(Context context) {
this(context, null);
}
public CustomRadioGroup(Context context, AttributeSet attrs) {
super(context, attrs);
this.mContext = context;
rowViews = new ArrayList<>();
}
//设置水平间距（单位dp）
public void setHorizontalSpacing(int horizontalSpacing_dp) {
this.horizontalSpacing = dip2px(mContext, horizontalSpacing_dp);
}
//设置垂直间距（单位dp）
public void setVerticalSpacing(int verticalSpacing_dp) {
this.verticalSpacing = dip2px(mContext, verticalSpacing_dp);
;
}
public int dip2px(Context context, float dipValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dipValue * scale + 0.5f);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
rowViews.clear();//清空集合
//获取屏幕总宽度(包含默认paddingleft和paddingright)
int width = MeasureSpec.getSize(widthMeasureSpec);
//去除默认宽带与实际宽带进行比较
int nopaddingWidth = width - getPaddingLeft() - getPaddingRight();
RowView rowView = null;
//遍历所有的view进行分行
for (int i = 0; i < getChildCount(); i++) {
View childView = getChildAt(i);//获取对应的view
childView.measure(0, 0);//通知父view进行测量
if (rowView == null) {
rowView = new RowView();
}
if (rowView.getRowViews().size() == 0) {//如果当前行一个view都没有，，直接添加，不用比较
rowView.addChidView(childView);
} else if (rowView.getRowWidth() + horizontalSpacing + childView.getMeasuredWidth() > nopaddingWidth) {
//如果当前的行宽度+水平间距+当前view的宽带大于nopaddingWidth，则需要换行
rowViews.add(rowView);//将之前的行保存起来
rowView = new RowView();//重新创建一行，，将当前的view保存起来
rowView.addChidView(childView);
} else {
rowView.addChidView(childView);//当前childView添加后没有超出nopaddingWidth，可以将childView添加到当前行
}
// 如果当前childView是最后一个子View，会造成最后一行line丢失
if (i == getChildCount() - 1) {
rowViews.add(rowView);
}
}
//计算layout所有行需要的高度
int heght = getPaddingTop() + getPaddingBottom();//加上padding值
for (int i = 0; i < rowViews.size(); i++) {
heght += rowViews.get(i).getRowHeight();//添加每行高度
}
heght += (rowViews.size() - 1) * verticalSpacing;//添加垂直间距高度
setMeasuredDimension(width, heght);//向父view申请宽带和高度
if (getChildCount() == 0) {
setMeasuredDimension(0, 0);
}
}
//将每个view放到对应的位置
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
int paddingLeft = getPaddingLeft();
int paddingTop = getPaddingTop();
for (int i = 0; i < rowViews.size(); i++) {
RowView rowView = rowViews.get(i);//获取到当前的line对象
//后面每一行的top值要相应的增加,当前行的top是上一行的top值+height+垂直间距
if (i > 0) {
paddingTop += rowViews.get(i - 1).getRowHeight() + verticalSpacing;
}
List viewList = rowView.getRowViews();//获取line的子View集合
for (int j = 0; j < viewList.size(); j++) {
View childView = viewList.get(j);//获取当前的子View
if (j == 0) {
//每行的第一个子View,需要靠左边摆放
childView.layout(paddingLeft, paddingTop, paddingLeft + childView.getMeasuredWidth(),
paddingTop + childView.getMeasuredHeight());
} else {
//摆放后面的子View，需要参考前一个子View的right
View preView = viewList.get(j - 1);//获取前一个子View
int left = preView.getRight() + horizontalSpacing;//前一个VIew的right+水平间距
childView.layout(left, preView.getTop(), left + childView.getMeasuredWidth(), preView.getBottom());
}
}
}
}
public interface OnclickListener{
void OnText(String text);
}
class RowView {
private List lineViews;//用于存放每行的view
private int rowWidth;//行宽
private int rowHeight;//行高
public RowView() {
lineViews = new ArrayList<>();
}
public List getRowViews() {
return lineViews;
}
public int getRowWidth() {
return rowWidth;
}
public int getRowHeight() {
return rowHeight;
}
//存放view到rowViews
public void addChidView(View view) {
if (!lineViews.contains(view)) {
((RadioButton)view).setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(listener!=null){
listener.OnText(((RadioButton)v).getText().toString().trim());
}
}
});
//更新高度和宽度
if (lineViews.size() == 0) {
//第一次添加view,不用添加水平间距
rowWidth = view.getMeasuredWidth();
} else {
//不是第一次添加，需要添加水平间距
rowWidth += view.getMeasuredWidth() + horizontalSpacing;
}
//height应该是所有子view中高度最大的那个
rowHeight = Math.max(view.getMeasuredHeight(), rowHeight);
lineViews.add(view);
}
}
}
}
Activity使用方法
CustomRadioGroup customRadioGroup1 = (CustomRadioGroup) findViewById(R.id.customRadioGroup);
setSpacing(customRadioGroup1,12,8);
for (int i = 0; i < str1.length; i++) {
RadioButton radioButton = (RadioButton) this.getLayoutInflater().inflate(R.layout.radiobutton_addcart, null); radioButton.setText(str1[i]);
customRadioGroup1.addView(radioButton);
}customRadioGroup1.setListener(new CustomRadioGroup.OnclickListener() {
@Override public void OnText(String text) {
text1 = text;
mTextView.setText(text1 + text2 + text3);
}});