Activity、BroadcastReceiver、Service共同工作的简单例子

? Activity 好像是應用程式的眼睛，提供與User 互動之窗。

? BroadcastReceiver 好像是耳朵，接收來自各方的Intent。

? Service 好像是手，提供符合Intent 意圖之服務。

10.2.1 操作情境：

1. 此程式一開始，畫面出現兩個按鈕如下：

2. 按下<call_service>按鈕，暫停15 秒：

3. 等待15 秒後，委託Alarm Manager 發出intent。當BroadcastReceiver 接到intent時，就啟動NotifyService，此服務會回傳字串，顯示於ac01 畫面的Title 區域：

4. 按下<Exit>，程式就結束了。

10.2.2 撰寫步驟：
Step-1: 建立Android 專案：kx02。
Step-2: 撰寫BroadcastReceiver 的子類別：AlarmReceiver，其程式碼如下：、

package com.misoo.kx02;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class AlarmReceiver extends BroadcastReceiver {
@Override public void onReceive(Context context, Intent intent) {
context.startService(new Intent(context, NotifyService.class));
}}

Step-3: 撰寫Service 的子類別：NotifyService，其程式碼如下：

package com.misoo.kx02;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
public class NotifyService extends Service{
@Override protected void onCreate() {
ac01 app = ac01.getApp();
app.btEvent("from NotifyService"); }
@Override public IBinder onBind(Intent intent) { return null; }
}

Step-4: 撰寫Activity 的子類別：ac01，其程式碼如下：

package com.misoo.kx02;
import java.util.Calendar;
import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
public class ac01 extends Activity implements OnClickListener{
private static ac01 appRef = null;
private Button btn, btn2; boolean k = false;
@Override protected void onCreate(Bundle icicle) {
super.onCreate(icicle);
appRef = this; setContentView(R.layout.cs);
btn = (Button)findViewById(R.id.call_service);
btn.setOnClickListener(this);
btn2 = (Button)findViewById(R.id.exit);
btn2.setOnClickListener(this);
}
public static ac01 getApp() { return appRef; }
public void btEvent( String data ) { setTitle(data); }
public void onClick(View arg0) {
if(arg0 == btn){
setTitle("Waiting... Alarm=15");
Intent intent = new Intent(ac01.this, AlarmReceiver.class);
PendingIntent p_intent = PendingIntent.getBroadcast(ac01.this, 0, intent, 0);
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.SECOND, 15);
// Schedule the alarm!
AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), p_intent); }
if(arg0 == btn2){
Intent intent = new Intent(ac01.this, AlarmReceiver.class);
PendingIntent p_intent = PendingIntent.getBroadcast(ac01.this, 0, intent, 0);
AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
am.cancel(p_intent); finish();
}}}

Step-5: 修改AndroidManifest.xml 的內容，更改為：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.misoo.kx02">
<application android:icon="@drawable/icon">
<activity android:name=".ac01" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".AlarmReceiver">
</receiver>
<service android:name=".NotifyService">
</service>
</application>
</manifest>