最近在做项目的时候，设计小哥给到了如下需求：

image.png

看上去简单，xml写起来：

<RadioGroup
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal">

                <RadioButton
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:text="xxx" />

                <RadioButton
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:text="xxx" />
            </LinearLayout>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal">

                <RadioButton
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:text="xxx" />

                <RadioButton
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:text="xxx" />
            </LinearLayout>
        </RadioGroup>

然而悲伤的事情来了，RadioGroup失去了它的单选功能，有且只有同一行的RadioButton可以单选。这是怎么回事呢？看看RadioGroup源码：

    @Override
    public void addView(View child, int index, ViewGroup.LayoutParams params) {
        if (child instanceof RadioButton) {
            final RadioButton button = (RadioButton) child;
            if (button.isChecked()) {
                mProtectFromCheckedChange = true;
                if (mCheckedId != -1) {
                    setCheckedStateForView(mCheckedId, false);
                }
                mProtectFromCheckedChange = false;
                setCheckedId(button.getId());
            }
        }

        super.addView(child, index, params);
    }

这里仅仅判断了RadioButton！这限制就大了。

当然解决方案也有多种：
1.重写RadioGroup，在子View的操作上做文章。
2.布局不变，动态的判断点击的RadioButton来清除其它的RadioGroup。
3.使用RecyclerView来刷新整个列表

我使用到的方法就是第三种，原因在于RecyclerView通过GridLayoutManager可以动态的变换整个列表的列数(非常实用)，而且不用去写RadioGroup里面的布局结构，只需要根据传入的List即可轻松实现。
话不多说，快看看代码吧
布局：

<RadioGroup
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <android.support.v7.widget.RecyclerView
                android:id="@+id/radio_rv"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
</RadioGroup>

是不是很简单啊

RecyclerView rv = UiUtils.find(view, R.id.radio_rv);
RadioRecycleAdapter radioAdapter = new RadioRecycleAdapter(mApplication, valueList);
radioAdapter.setOnItemClickListener((holder, pos) -> {
    //TODO
});
rv.setLayoutManager(new GridLayoutManager(mApplication, 2));
rv.setAdapter(radioAdapter);
rv.addItemDecoration(new SpaceItemDecoration(49));

public class RadioRecycleAdapter extends RecyclerView.Adapter<RadioRecycleAdapter.MyViewHolder> {

    private Context mContext;
    private List<String> mDatas;
    private int mSelectedItem = -1;

    public interface OnItemClickListener {
        void onItemClick(String holder, int pos);
    }

    private OnItemClickListener mListener;

    public void setOnItemClickListener(OnItemClickListener listener) {
        this.mListener = listener;
    }

    public RadioRecycleAdapter(Context mContext, List<String> datas) {
        this.mContext = mContext;
        this.mDatas = datas;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        MyViewHolder holder = new MyViewHolder(LayoutInflater.from(mContext).inflate(R.layout.item_radio, parent, false));
        return holder;
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        holder.radioButton.setText(mDatas.get(position));
        holder.radioButton.setChecked(position == mSelectedItem);
        holder.radioButton.setTag(position);
        holder.radioButton.setOnClickListener(v -> {
            mSelectedItem = (int) v.getTag();
            notifyItemRangeChanged(0, mDatas.size());
            if (mListener != null) {
                mListener.onItemClick(mDatas.get(holder.getLayoutPosition()), holder.getLayoutPosition());
            }
        });
    }

    @Override
    public int getItemCount() {
        return mDatas.size();
    }

    public void addData(String data, int pos) {
        mDatas.add(pos, data);
        notifyItemInserted(pos);
    }

    public void removeData(int pos) {
        mDatas.remove(pos);

        notifyDataSetChanged();
        notifyItemRemoved(pos);
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {
        RadioButton radioButton;

        public MyViewHolder(View itemView) {
            super(itemView);

            radioButton = (RadioButton) itemView.findViewById(R.id.radio_rb);
        }
    }
}

效果可以看最上面的图片。Over