簡單概括一下原理：要完成單選框顯示，我們需要使用到RadioGroup和RadioButton(單選框)，RadioGroup用於對單選框進行分組，相同組內的單選框只有一個單選框能被選中。(例子程式碼請見下方備註欄)
 RadioGroup.check(R.id.dotNet);將id名為dotNet的單選框設定成選中狀態。
(RadioButton) findViewById(radioGroup.getCheckedRadioButtonId());//獲取被選中的單選框。
RadioButton.getText();//獲取單選框的值
呼叫setOnCheckedChangeListener()方法，處理單選框被選擇事件，把RadioGroup.OnCheckedChangeListener例項作為引數傳入

1、佈局檔案：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <RadioGroup
        android:id="@+id/radioGroup1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="78dp"
        android:layout_marginTop="85dp" >

        <RadioButton
            android:id="@+id/radio0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="true"
            android:text="@string/text_java" />

        <RadioButton
            android:id="@+id/radio1"
            android:layout_width="wrap_content"
            android:layout_height="73dp"
            android:text="@string/text_NET" />

        <RadioButton
            android:id="@+id/radio2"
            android:layout_width="162dp"
            android:layout_height="95dp"
            android:text="@string/text_PHP" />
    </RadioGroup>

</RelativeLayout>
 

2、佈局檔案中引用的string.xml的值

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">lession16-radio</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>
    
   
	<string name="text_java">JAVA專業</string>
    
	<string name="text_NET">NET專業</string>
	<string name="text_PHP">PHP專業</string>
</resources>
 

3、MainActivity中的程式碼：

package com.example.lession16_radio;

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

public class MainActivity extends Activity {
	private RadioGroup group_temo;
	private RadioButton checkRadioButton;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		group_temo=(RadioGroup) findViewById(R.id.radioGroup1);
		
		//改變預設值
		group_temo.check(R.id.radio2);
		
		//獲取預設被選中值
		checkRadioButton=(RadioButton) group_temo.findViewById(group_temo.getCheckedRadioButtonId());
		
		
		Toast.makeText(this, "預設的選項的值是:"+checkRadioButton.getText(), Toast.LENGTH_LONG).show();
		
		//註冊事件
		group_temo.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
			
			@Override
			public void onCheckedChanged(RadioGroup group, int checkedId) {
				//點選事件獲取的選擇物件
				checkRadioButton=(RadioButton) group_temo.findViewById(checkedId);
				Toast.makeText(getApplicationContext(), "獲取的ID的物件"+checkRadioButton.getText(), Toast.LENGTH_LONG).show();
				
			}
		});
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

效果圖：

佈局有點不美觀，以實現效果為主，呵呵！