单项选择（RadioGroup）

RadioGroup 是 LinearLayout 的子类，继承关系例如以下：

android.view.ViewGroup
android.widget.LinearLayout
android.widget.RadioGroup

RadioGroup 类方法

RadioGroup 演示样例

完整project：http://download.csdn.net/detail/sweetloveft/9402088
下述程序中，主要学习 RadioGroup 的使用方法，须要注意单选button的处理逻辑是通过监听 RadioGroup 完毕的，详细处理哪个单选button则是通过 getId() 完毕的。

1.MainActivity.java

package com.sweetlover.activity;

import com.sweetlover.radiogroupdemo.R;

import android.app.Activity;

import android.os.Bundle;

import android.widget.RadioButton;

import android.widget.RadioGroup;

import android.widget.Toast;

import android.widget.RadioGroup.OnCheckedChangeListener;

import android.widget.TextView;

public class MainActivity extends Activity {

	private static final int BTN_NUM = 6;

	private TextView textView = null;

	private RadioGroup radioGroup = null;

	private RadioButton[] radioButton = null;

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		// TODO Auto-generated method stub

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		radioButton = new RadioButton[BTN_NUM];

		textView = (TextView)findViewById(R.id.textView1);

		radioGroup = (RadioGroup)findViewById(R.id.radioGroup);

		radioButton[0] = (RadioButton)findViewById(R.id.radioButton1);

		radioButton[1] = (RadioButton)findViewById(R.id.radioButton2);

		radioButton[2] = (RadioButton)findViewById(R.id.radioButton3);

		radioButton[3] = (RadioButton)findViewById(R.id.radioButton4);

		radioButton[4] = (RadioButton)findViewById(R.id.radioButton5);

		radioButton[5] = (RadioButton)findViewById(R.id.radioButton6);

		radioGroup.setOnCheckedChangeListener(new RadioGroupCheckedListener());

	}

	class RadioGroupCheckedListener implements OnCheckedChangeListener {

		@Override

		public void onCheckedChanged(RadioGroup group, int checkedId) {

			// TODO Auto-generated method stub

			for (int i = 0; i < BTN_NUM; i++) {

				if (checkedId == radioButton[i].getId() && radioButton[i].isChecked()) {

					CharSequence text = radioButton[i].getText();

					textView.setText(text);

					Toast.makeText(MainActivity.this, text, Toast.LENGTH_SHORT).show();

					break;

				}

			}

		}

	}

}

2.activity_main.xml

<?

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

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:padding="30dp"

    android:orientation="vertical" >

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_gravity="center"

        android:text="@string/system"

        android:textAppearance="?

android:attr/textAppearanceMedium" />

    <RadioGroup

        android:id="@+id/radioGroup"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:padding="30dp" >

        <RadioButton

            android:id="@+id/radioButton1"

            android:layout_width="160dp"

            android:layout_height="wrap_content"

            android:layout_gravity="center"

            android:text="@string/os1" />

        <RadioButton

            android:id="@+id/radioButton2"

            android:layout_width="160dp"

            android:layout_height="wrap_content"

            android:layout_gravity="center"

            android:text="@string/os2" />

        <RadioButton

            android:id="@+id/radioButton3"

            android:layout_width="160dp"

            android:layout_height="wrap_content"

            android:layout_gravity="center"

            android:text="@string/os3" />

        <RadioButton

            android:id="@+id/radioButton4"

            android:layout_width="160dp"

            android:layout_height="wrap_content"

            android:layout_gravity="center"

            android:text="@string/os4" />

        <RadioButton

            android:id="@+id/radioButton5"

            android:layout_width="160dp"

            android:layout_height="wrap_content"

            android:layout_gravity="center"

            android:text="@string/os5" />

        <RadioButton

            android:id="@+id/radioButton6"

            android:layout_width="160dp"

            android:layout_height="wrap_content"

            android:layout_gravity="center"

            android:text="@string/os6" />

    </RadioGroup>

</LinearLayout>

3.string.xml

<resources>

    <string name="app_name">RadioGroupDemo</string>

    <string name="system">操作系统</string>

    <string name="os1">Android</string>

    <string name="os2">Sysbian</string>

    <string name="os3">WinCE</string>

    <string name="os4">PalmOS</string>

    <string name="os5">Linux</string>

    <string name="os6">iPhoneOS</string>

</resources>

4.AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.sweetlover.radiogroupdemo"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="19" />

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity android:name="com.sweetlover.activity.MainActivity">

            <intent-filter>

                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>

            </intent-filter>

        </activity>

    </application>

</manifest>