RadioGroup拦截点击并判断

需求

每次点击radiobutton前需要弹框提示用户，点确定则切换radiobutton，点取消什么也不做。

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.RadioButton;
import android.widget.RadioGroup;


public class MyRadioGroup extends RadioGroup {
    private final String TAG = "laocuo";

    private int checkId;
    private AlertDialog dialog;

    public MyRadioGroup(Context context, AttributeSet attrs) {
        super(context, attrs);
        dialog = new AlertDialog.Builder(getContext())
                .setTitle("title")
                .setMessage("message")
                .setPositiveButton("yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface anInterface, int i) {
                        Log.d(TAG, "setPositiveButton");
                        check(checkId);
                    }
                })
                .setNegativeButton("no", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface anInterface, int i) {
                        Log.d(TAG, "setNegativeButton");
                    }
                })
                .create();
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        int count = getChildCount();
        for (int i=0;i