最近项目原因，需要编写一后台运行的程序，在给定时间间隔下进行拍照，关键技术主要是：1、开启服务；2、在不不预览的情况下，进行拍照操作。3、使用AlarmManager进行定时操作。

资源清单如下：

android:minSdkVersion="13"
android:targetSdkVersion="15" />

android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
android:name=".MainActivity"
android:label="@string/title_activity_main" >

服务代码如下：

package com.yang.service;

import java.io.IOException;

import android.app.AlarmManager;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.hardware.Camera;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import android.view.SurfaceView;
import android.widget.Toast;

import com.yang.handle.PhotoHandler;
import com.yang.testservice.MainActivity;
import com.yang.testservice.R;

public class LocalService extends Service {

private AlarmManager am = null;
private Camera camera;

private final IBinder mBinder = new LocalBinder();

private NotificationManager mNM;

private int NOTIFICATION = R.string.local_service_started;

/**
* Class for clients to access. Because we know this service always runs in
* the same process as its clients, we don't need to deal with IPC.
*/
public class LocalBinder extends Binder {
public LocalService getService() {
return LocalService.this;
}

}

@Override
public void onCreate() {
mNM = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
showNotification();
init();
}

private void init() {
am = (AlarmManager) getSystemService(ALARM_SERVICE);

camera = openFacingBackCamera();

// 注册广播
IntentFilter filter = new IntentFilter();
filter.addAction("com.vegetables_source.alarm");
registerReceiver(alarmReceiver, filter);

Intent intent = new Intent();
intent.setAction("com.vegetables_source.alarm");
PendingIntent pi = PendingIntent.getBroadcast(this, 0, intent, 0);

am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(),
1000 * 10, pi);// 马上开始，每1分钟触发一次
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i("LocalService", "Received start id " + startId + ": " + intent);

return START_STICKY;
}

@Override
public void onDestroy() {
mNM.cancel(NOTIFICATION);

cancelAlertManager();

if (camera != null) {
camera.release();
camera = null;
}

Toast.makeText(this, R.string.local_service_stopped, Toast.LENGTH_SHORT)
.show();
}

@Override
public IBinder onBind(Intent intent) {
return mBinder;
}

/**
* Show a notification while this service is running.
*/
private void showNotification() {
CharSequence text = getText(R.string.local_service_started);

Notification notification = new Notification(R.drawable.stat_running,
text, System.currentTimeMillis());

PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
new Intent(this, MainActivity.class), 0);

notification.setLatestEventInfo(this,
getText(R.string.local_service_label), text, contentIntent);

mNM.notify(NOTIFICATION, notification);
}