Android-RadioButton单项选择Demo

package com.lxt008;

import com.lxt008.R;

import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class Activity01 extends Activity
{
    /**
     * 创建TextView对象
     * 创建RadioGroup对象
     * 创建4个RadioButton对象
     */
    TextView        m_TextView;
    RadioGroup        m_RadioGroup;
    RadioButton        m_Radio1, m_Radio2, m_Radio3, m_Radio4;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        /**
         * 获得TextView对象
         * 获得RadioGroup对象
         * 获得4个RadioButton对象
         */
        m_TextView = (TextView) findViewById(R.id.TextView01);
        m_RadioGroup = (RadioGroup) findViewById(R.id.RadioGroup01);
        m_Radio1 = (RadioButton) findViewById(R.id.RadioButton1);
        m_Radio2 = (RadioButton) findViewById(R.id.RadioButton2);
        m_Radio3 = (RadioButton) findViewById(R.id.RadioButton3);
        m_Radio4 = (RadioButton) findViewById(R.id.RadioButton4);

        /* 设置事件监听  */
        m_RadioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId)
            {
                // TODO Auto-generated method stub
                if (checkedId == m_Radio2.getId())
                {
                    DisplayToast("正确答案：" + m_Radio2.getText() + "，恭喜你，回答正确！");
                }
                else
                {
                    DisplayToast("请注意，回答错误！");
                }
            }
        });
    }
    
    /* 显示Toast  */
    public void DisplayToast(String str)
    {
        Toast toast = Toast.makeText(this, str, Toast.LENGTH_LONG);
        //设置toast显示的位置
        toast.setGravity(Gravity.TOP, 0, 220);
        //显示该Toast
        toast.show();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <TextView  
    android:id="@+id/TextView01"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
  <RadioGroup
    android:id="@+id/RadioGroup01"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:layout_x="3px"
    android:layout_y="54px" 
    >
    <RadioButton
      android:id="@+id/RadioButton1"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/RadioButton1"
    />
    <RadioButton
      android:id="@+id/RadioButton2"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/RadioButton2"
    />
    <RadioButton
      android:id="@+id/RadioButton3"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/RadioButton3"
    />
    <RadioButton
      android:id="@+id/RadioButton4"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/RadioButton4"
    />
    </RadioGroup>    
</LinearLayout>