最近在做一个埋点的sdk，由于埋点是分批上传的，不是每次都上传，所以会有个进程保活的机制，这也是自研推送的实现技术之一：如何保证Android进程的存活。
对于Android来说，保活主要有以下一些方法：
开启前台Service（效果好，推荐） Service中循环播放一段无声音频（效果较好，但耗电量高，谨慎使用） 双进程守护（Android 5.0前有效） JobScheduler（Android 5.0后引入，8.0后失效） 1 像素activity保活方案（不推荐） 广播锁屏、自定义锁屏（不推荐） 第三方推送SDK唤醒（效果好，缺点是第三方接入）
下面是具体的实现方案：
1.监听锁屏广播，开启1个像素的Activity
最早见到这种方案的时候是2015年，有个FM的app为了向投资人展示月活，在Android应用中开启一个1像素的Activity。
由于Activity的级别是比较高的，所以开启1个像素的Activity的方式就可以保证进程是不容易被杀掉的。
具体来说，定义一个1像素的Activity，在该Activity中动态注册自定义的广播。
class OnePixelActivity : AppCompatActivity() { private lateinit var br: BroadcastReceiver override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) //设定一像素的activity val window = window window.setGravity(Gravity.LEFT or Gravity.TOP) val params = window.attributes params.x = 0 params.y = 0 params.height = 1 params.width = 1 window.attributes = params //在一像素activity里注册广播接受者 接受到广播结束掉一像素 br = object : BroadcastReceiver() { override fun onReceive(context: Context, intent: Intent) { finish() } } registerReceiver(br, IntentFilter("finish activity")) checkScreenOn() } override fun onResume() { super.onResume() checkScreenOn() } override fun onDestroy() { try { //销毁的时候解锁广播 unregisterReceiver(br) } catch (e: IllegalArgumentException) { } super.onDestroy() } /** * 检查屏幕是否点亮 */ private fun checkScreenOn() { val pm = this@OnePixelActivity.getSystemService(Context.POWER_SERVICE) as PowerManager val isScreenOn = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH) { pm.isInteractive } else { pm.isScreenOn } if (isScreenOn) { finish() } }}
2， 双进程守护
双进程守护，在Android 5.0前是有效的，5.0之后就不行了。首先，我们定义定义一个本地服务，在该服务中播放无声音乐，并绑定远程服务
class LocalService : Service() { private var mediaPlayer: MediaPlayer? = null private var mBilder: MyBilder? = null override fun onCreate() { super.onCreate() if (mBilder == null) { mBilder = MyBilder() } } override fun onBind(intent: Intent): IBinder? { return mBilder } override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int { //播放无声音乐 if (mediaPlayer == null) { mediaPlayer = MediaPlayer.create(this, R.raw.novioce) //声音设置为0 mediaPlayer?.setVolume(0f, 0f) mediaPlayer?.isLooping = true//循环播放 play() } //启用前台服务，提升优先级 if (KeepLive.foregroundNotification != null) { val intent2 = Intent(applicationContext, NotificationClickReceiver::class.java) intent2.action = NotificationClickReceiver.CLICK_NOTIFICATION val notification = NotificationUtils.createNotification(this, KeepLive.foregroundNotification!!.getTitle(), KeepLive.foregroundNotification!!.getDescription(), KeepLive.foregroundNotification!!.getIconRes(), intent2) startForeground(13691, notification) } //绑定守护进程 try { val intent3 = Intent(this, RemoteService::class.java) this.bindService(intent3, connection, Context.BIND_ABOVE_CLIENT) } catch (e: Exception) { } //隐藏服务通知 try { if (Build.VERSION.SDK_INT < 25) { startService(Intent(this, HideForegroundService::class.java)) } } catch (e: Exception) { } if (KeepLive.keepLiveService != null) { KeepLive.keepLiveService!!.onWorking() } return Service.START_STICKY } private fun play() { if (mediaPlayer != null && !mediaPlayer!!.isPlaying) { mediaPlayer?.start() } } private inner class MyBilder : GuardAidl.Stub() { @Throws(RemoteException::class) override fun wakeUp(title: String, discription: String, iconRes: Int) { } } private val connection = object : ServiceConnection { override fun onServiceDisconnected(name: ComponentName) { val remoteService = Intent(this@LocalService, RemoteService::class.java) this@LocalService.startService(remoteService) val intent = Intent(this@LocalService, RemoteService::class.java) this@LocalService.bindService(intent, this, Context.BIND_ABOVE_CLIENT) } override fun onServiceConnected(name: ComponentName, service: IBinder) { try { if (mBilder != null && KeepLive.foregroundNotification != null) { val guardAidl = GuardAidl.Stub.asInterface(service) guardAidl.wakeUp(KeepLive.foregroundNotification?.getTitle(), KeepLive.foregroundNotification?.getDescription(), KeepLive.foregroundNotification!!.getIconRes()) } } catch (e: RemoteException) { e.printStackTrace() } } } override fun onDestroy() { super.onDestroy() unbindService(connection) if (KeepLive.keepLiveService != null) { KeepLive.keepLiveService?.onStop() } }}
然后再定义一个远程服务，绑定本地服务。
class RemoteService : Service() { private var mBilder: MyBilder? = null override fun onCreate() { super.onCreate() if (mBilder == null) { mBilder = MyBilder() } } override fun onBind(intent: Intent): IBinder? { return mBilder } override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int { try { this.bindService(Intent(this@RemoteService, LocalService::class.java), connection, Context.BIND_ABOVE_CLIENT) } catch (e: Exception) { } return Service.START_STICKY } override fun onDestroy() { super.onDestroy() unbindService(connection) } private inner class MyBilder : GuardAidl.Stub() { @Throws(RemoteException::class) override fun wakeUp(title: String, discription: String, iconRes: Int) { if (Build.VERSION.SDK_INT < 25) { val intent = Intent(applicationContext, NotificationClickReceiver::class.java) intent.action = NotificationClickReceiver.CLICK_NOTIFICATION val notification = NotificationUtils.createNotification(this@RemoteService, title, discription, iconRes, intent) this@RemoteService.startForeground(13691, notification) } } } private val connection = object : ServiceConnection { override fun onServiceDisconnected(name: ComponentName) { val remoteService = Intent(this@RemoteService, LocalService::class.java) this@RemoteService.startService(remoteService) this@RemoteService.bindService(Intent(this@RemoteService, LocalService::class.java), this, Context.BIND_ABOVE_CLIENT) } override fun onServiceConnected(name: ComponentName, service: IBinder) {} }}/** * 通知栏点击广播接受者 */class NotificationClickReceiver : BroadcastReceiver() { companion object { const val CLICK_NOTIFICATION = "CLICK_NOTIFICATION" } override fun onReceive(context: Context, intent: Intent) { if (intent.action == NotificationClickReceiver.CLICK_NOTIFICATION) { if (KeepLive.foregroundNotification != null) { if (KeepLive.foregroundNotification!!.getForegroundNotificationClickListener() != null) { KeepLive.foregroundNotification!!.getForegroundNotificationClickListener()?.foregroundNotificationClick(context, intent) } } } }}
3，JobScheduler
JobScheduler是Android从5.0增加的支持一种特殊的任务调度机制，可以用它来实现进程保活，不过在Android8.0系统中，此种方法也失效。
首先，我们定义一个JobService，开启本地服务和远程服务。
@SuppressWarnings(value = ["unchecked", "deprecation"])@RequiresApi(Build.VERSION_CODES.LOLLIPOP)class JobHandlerService : JobService() { private var mJobScheduler: JobScheduler? = null override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int { var startId = startId startService(this) if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { mJobScheduler = getSystemService(Context.JOB_SCHEDULER_SERVICE) as JobScheduler val builder = JobInfo.Builder(startId++, ComponentName(packageName, JobHandlerService::class.java.name)) if (Build.VERSION.SDK_INT >= 24) { builder.setMinimumLatency(JobInfo.DEFAULT_INITIAL_BACKOFF_MILLIS) //执行的最小延迟时间 builder.setOverrideDeadline(JobInfo.DEFAULT_INITIAL_BACKOFF_MILLIS) //执行的最长延时时间 builder.setMinimumLatency(JobInfo.DEFAULT_INITIAL_BACKOFF_MILLIS) builder.setBackoffCriteria(JobInfo.DEFAULT_INITIAL_BACKOFF_MILLIS, JobInfo.BACKOFF_POLICY_LINEAR)//线性重试方案 } else { builder.setPeriodic(JobInfo.DEFAULT_INITIAL_BACKOFF_MILLIS) } builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY) builder.setRequiresCharging(true) // 当插入充电器，执行该任务 mJobScheduler?.schedule(builder.build()) } return Service.START_STICKY } private fun startService(context: Context) { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { if (KeepLive.foregroundNotification != null) { val intent = Intent(applicationContext, NotificationClickReceiver::class.java) intent.action = NotificationClickReceiver.CLICK_NOTIFICATION val notification = NotificationUtils.createNotification(this, KeepLive.foregroundNotification!!.getTitle(), KeepLive.foregroundNotification!!.getDescription(), KeepLive.foregroundNotification!!.getIconRes(), intent) startForeground(13691, notification) } } //启动本地服务 val localIntent = Intent(context, LocalService::class.java) //启动守护进程 val guardIntent = Intent(context, RemoteService::class.java) startService(localIntent) startService(guardIntent) } override fun onStartJob(jobParameters: JobParameters): Boolean { if (!isServiceRunning(applicationContext, "com.xiyang51.keeplive.service.LocalService") || !isServiceRunning(applicationContext, "$packageName:remote")) { startService(this) } return false } override fun onStopJob(jobParameters: JobParameters): Boolean { if (!isServiceRunning(applicationContext, "com.xiyang51.keeplive.service.LocalService") || !isServiceRunning(applicationContext, "$packageName:remote")) { startService(this) } return false } private fun isServiceRunning(ctx: Context, className: String): Boolean { var isRunning = false val activityManager = ctx .getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager val servicesList = activityManager .getRunningServices(Integer.MAX_VALUE) val l = servicesList.iterator() while (l.hasNext()) { val si = l.next() if (className == si.service.className) { isRunning = true } } return isRunning }}
4，提高Service优先级
在onStartCommand()方法中开启一个通知，提高进程的优先级。注意：从Android 8.0（API级别26）开始，所有通知必须要分配一个渠道，对于每个渠道，可以单独设置视觉和听觉行为。然后用户可以在设置中修改这些设置，根据应用程序来决定哪些通知可以显示或者隐藏。
首先，定义一个通知工具类，此工具栏兼容Android 8.0。
class NotificationUtils(context: Context) : ContextWrapper(context) { private var manager: NotificationManager? = null private var id: String = context.packageName + "51" private var name: String = context.packageName private var context: Context = context private var channel: NotificationChannel? = null companion object { @SuppressLint("StaticFieldLeak") private var notificationUtils: NotificationUtils? = null fun createNotification(context: Context, title: String, content: String, icon: Int, intent: Intent): Notification? { if (notificationUtils == null) { notificationUtils = NotificationUtils(context) } var notification: Notification? = null notification = if (Build.VERSION.SDK_INT >= 26) { notificationUtils?.createNotificationChannel() notificationUtils?.getChannelNotification(title, content, icon, intent)?.build() } else { notificationUtils?.getNotification_25(title, content, icon, intent)?.build() } return notification } } @RequiresApi(api = Build.VERSION_CODES.O) fun createNotificationChannel() { if (channel == null) { channel = NotificationChannel(id, name, NotificationManager.IMPORTANCE_MIN) channel?.enableLights(false) channel?.enableVibration(false) channel?.vibrationPattern = longArrayOf(0) channel?.setSound(null, null) getManager().createNotificationChannel(channel) } } private fun getManager(): NotificationManager { if (manager == null) { manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager } return manager!! } @RequiresApi(api = Build.VERSION_CODES.O) fun getChannelNotification(title: String, content: String, icon: Int, intent: Intent): Notification.Builder { //PendingIntent.FLAG_UPDATE_CURRENT 这个类型才能传值 val pendingIntent = PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT) return Notification.Builder(context, id) .setContentTitle(title) .setContentText(content) .setSmallIcon(icon) .setAutoCancel(true) .setContentIntent(pendingIntent) } fun getNotification_25(title: String, content: String, icon: Int, intent: Intent): NotificationCompat.Builder { val pendingIntent = PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT) return NotificationCompat.Builder(context, id) .setContentTitle(title) .setContentText(content) .setSmallIcon(icon) .setAutoCancel(true) .setVibrate(longArrayOf(0)) .setSound(null) .setLights(0, 0, 0) .setContentIntent(pendingIntent) }}
5，Workmanager方式
Workmanager是Android JetPac中的一个API，借助Workmanager，我们可以用它来实现应用饿保活。使用前，我们需要依赖Workmanager库，如下：
implementation "android.arch.work:work-runtime:1.0.0-alpha06"
Worker是一个抽象类，用来指定需要执行的具体任务。
public class KeepLiveWork extends Worker { private static final String TAG = "KeepLiveWork"; @NonNull @Override public WorkerResult doWork() { Log.d(TAG, "keep-> doWork: startKeepService"); //启动job服务 startJobService(); //启动相互绑定的服务 startKeepService(); return WorkerResult.SUCCESS; }}
然后，启动keepWork方法，
public void startKeepWork() { WorkManager.getInstance().cancelAllWorkByTag(TAG_KEEP_WORK); Log.d(TAG, "keep-> dowork startKeepWork"); OneTimeWorkRequest oneTimeWorkRequest = new OneTimeWorkRequest.Builder(KeepLiveWork.class) .setBackoffCriteria(BackoffPolicy.LINEAR, 5, TimeUnit.SECONDS) .addTag(TAG_KEEP_WORK) .build(); WorkManager.getInstance().enqueue(oneTimeWorkRequest); }
关于WorkManager，可以通过下面的文章来详细了解：WorkManager浅谈
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本文标题: 详解Android 8.0以上系统应用如何保活
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