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单项选择（RadioGroup）
RadioGroup 是 LinearLayout 的子类，继承关系如下：
android.view.ViewGroup
android.widget.LinearLayout
android.widget.RadioGroup
RadioGroup 类方法
RadioGroup 示例
完整工程：http://download.csdn.net/detail/sweetloveft/9402088
下述程序中，主要学习 RadioGroup 的用法，需要注意单选按钮的处理逻辑是通过监听 RadioGroup 完成的，具体处理哪个单选按钮则是通过 getId() 完成的。
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;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.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 {@Overridepublic void onCheckedChanged(RadioGroup group, int checkedId) {// TODO Auto-generated method stubfor (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" ><TextViewandroid: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" /><RadioGroupandroid:id="@+id/radioGroup"android:layout_width="match_parent"android:layout_height="wrap_content"android:padding="30dp" ><RadioButtonandroid:id="@+id/radioButton1"android:layout_width="160dp"android:layout_height="wrap_content"android:layout_gravity="center"android:text="@string/os1" /><RadioButtonandroid:id="@+id/radioButton2"android:layout_width="160dp"android:layout_height="wrap_content"android:layout_gravity="center"android:text="@string/os2" /><RadioButtonandroid:id="@+id/radioButton3"android:layout_width="160dp"android:layout_height="wrap_content"android:layout_gravity="center"android:text="@string/os3" /><RadioButtonandroid:id="@+id/radioButton4"android:layout_width="160dp"android:layout_height="wrap_content"android:layout_gravity="center"android:text="@string/os4" /><RadioButtonandroid:id="@+id/radioButton5"android:layout_width="160dp"android:layout_height="wrap_content"android:layout_gravity="center"android:text="@string/os5" /><RadioButtonandroid: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-sdkandroid:minSdkVersion="8"android:targetSdkVersion="19" /><applicationandroid: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>
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