布局文件main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Sex">

    <TextView
        android:id="@+id/show"
        android:textSize="20px"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="你的性别是：" />

    <RadioGroup
        android:id="@+id/sex"
        android:orientation="vertical"
        android:checkedButton="@+id/male"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
        <RadioButton
            android:id="@+id/male"
            android:text="男"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />
        <RadioButton
            android:id="@+id/female"
            android:text="女"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />
    </RadioGroup>

</LinearLayout>

定义Activity程序

package com.example.lenovo.myapplication;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;

public class Sex extends AppCompatActivity {

        private TextView show ;
        private RadioGroup sex ;
        private RadioButton male ;
        private RadioButton female ;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            this.show = (TextView) super.findViewById(R.id.show);
            this.sex = (RadioGroup) super.findViewById(R.id.sex);
            this.male = (RadioButton) super.findViewById(R.id.male);
            this.female = (RadioButton) super.findViewById(R.id.female);
            this.sex.setOnCheckedChangeListener(new OnCheckedChangeListenerImpl());
        }

        private class OnCheckedChangeListenerImpl implements RadioGroup.OnCheckedChangeListener {
            @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
                String temp = null;
                if (Sex.this.male.getId()==checkedId){
                    temp = Sex.this.male.getText().toString();
                }
                if (Sex.this.female.getId()==checkedId){
                    temp = Sex.this.female.getText().toString();
                }
                Sex.this.show.setText("你的性别是："+temp);
            }
        }
}