Android后台开启服务默默拍照

Android后台开启服务默默拍照

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：

<manifest xmlns:Android="http://schemas.android.com/apk/res/android"
    package="com.yang.testservice"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera.autofocus" />

    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.FLASHLIGHT" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <uses-feature android:name="android.hardware.camera.any" />

    <uses-sdk
        android:minSdkVersion="13"
        android:targetSdkVersion="15" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        <service android:name="com.yang.service.LocalService" />
    </application>

</manifest>

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);
 }

 private void cancelAlertManager() {
  Intent intent = new Intent();
  intent.setAction("com.vegetables_source.alarm");
  PendingIntent pi = PendingIntent.getBroadcast(this, 0, intent, 0);
  am.cancel(pi);

  // 注销广播
  unregisterReceiver(alarmReceiver);
 }

 BroadcastReceiver alarmReceiver = new BroadcastReceiver() {

  @Override
  public void onReceive(Context context, Intent intent) {
   if ("com.vegetables_source.alarm".equals(intent.getAction())) {

    if (camera != null) {
     SurfaceView dummy = new SurfaceView(getBaseContext());
     try {
      camera.setPreviewDisplay(dummy.getHolder());
     } catch (IOException e) {
      e.printStackTrace();
     }
     camera.startPreview();

     camera.takePicture(null, null, new PhotoHandler(
       getApplicationContext()));
    }

   }

  }
 };

 private Camera openFacingBackCamera() {
  Camera cam = null;
  Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
  ;
  for (int camIdx = 0, cameraCount = Camera.getNumberOfCameras(); camIdx < cameraCount; camIdx++) {
   Camera.getCameraInfo(camIdx, cameraInfo);
   if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
    try {
     cam = Camera.open(camIdx);
    } catch (RuntimeException e) {
     e.printStackTrace();
    }
   }
  }

  return cam;
 }
}

进行拍照存储的操作代码如下：

package com.yang.handle;

import java.io.File;
import java.io.FileOutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.os.Environment;
import android.widget.Toast;

public class PhotoHandler implements PictureCallback {

    private final Context context;

    public PhotoHandler(Context context) {
        this.context = context;
    }

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {

        File pictureFileDir = getDir();

        if (!pictureFileDir.exists() && !pictureFileDir.mkdirs()) {

            Toast.makeText(context, "Can't create directory to save image.",
                    Toast.LENGTH_LONG).show();
            return;

        }

        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss");
        String date = dateFormat.format(new Date());
        String photoFile = "Picture_" + date + ".jpg";

        String filename = pictureFileDir.getPath() + File.separator + photoFile;

        File pictureFile = new File(filename);
        System.out.println("filename is "+ filename);

        try {
            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();
            Toast.makeText(context, "New Image saved:" + photoFile,
                    Toast.LENGTH_LONG).show();
        } catch (Exception error) {
            Toast.makeText(context, "Image could not be saved.",
                    Toast.LENGTH_LONG).show();
        }
    }

    private File getDir() {
        File sdDir = Environment
          .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
        return new File(sdDir, "ServiceCamera");
    }
}

项目代码如下：

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