阅读《Android 从入门到精通》(10)——单项选择
16lz
2021-01-23
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" > <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>
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