Android应用保活实践

最近在做的项目中需要app在后台常驻，用于实时上传一些健康信息数据，便于后台实时查看用户的健康状况。自从Android7.0以上后台常驻实现越来越难，尤其是8.0及以上。关于保活的文章比比皆是，但是效果并不理想，关于保活的方法也就常说的哪几种，重点在于怎么组合运用。最终实现效果为：用户不主动强制杀死的话，能够一直存活(小米，华为，vivo，oppo，三星)。其中三星s8，华为nova2s用户强制杀死也能存活。

项目结构

image

常见的保活方案

关于Android应用保活的文章很多，这里不再阐述，可自行百度。重点在于运用这样方案来实现保活功能。

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代码实现

1.监听锁屏广播，开启1个像素的Activity。

在锁屏的时候启动一个1个像素的Activity，当用户解锁以后将这个Activity结束掉。

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

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 &amp;&amp; !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 &amp;&amp; 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()
        }
    }
}

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和JobService是安卓在api 21中增加的接口，用于在某些指定条件下执行后台任务。

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.播放无声音乐

这里使用的是有声的mp3文件，只是在代码中把声音设置成了0；如果使用真正的无声的音乐文件，在oppo手机上按下返回键会被立刻杀死，并且在三星手机，华为nova2s强制杀死也会被杀死，所有使用了有声的文件。

5.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。

定义一个通知工具类，兼容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)
    }
}

使用

将保活的功能封装成了一个单独的库，依赖该库即可。

app中使用：

KeepLive.startWork(this, KeepLive.RunMode.ROGUE, ForegroundNotification("Title", "message",
        R.mipmap.ic_launcher, object : ForegroundNotificationClickListener {
    override fun foregroundNotificationClick(context: Context, intent: Intent) {
        //点击通知回调

    }
}), object : KeepLiveService {
    override fun onStop() {
        //可能调用多次，跟onWorking匹配调用
    }

    override fun onWorking() {
        //一直存活，可能调用多次
    }
})

清单文件配置：

<!--权限配置-->
<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
<uses-permission android:name="android.permission.GET_TASKS" />
<uses-permission android:name="android.permission.REORDER_TASKS" />

 <!--保活相关配置-->
<receiver android:name="com.xiyang51.keeplive.receiver.NotificationClickReceiver" />
<activity android:name="com.xiyang51.keeplive.activity.OnePixelActivity" />

<service android:name="com.xiyang51.keeplive.service.LocalService" />
<service android:name="com.xiyang51.keeplive.service.HideForegroundService" />
<service
    android:name="com.xiyang51.keeplive.service.JobHandlerService"
    android:permission="android.permission.BIND_JOB_SERVICE" />
<service
    android:name="com.xiyang51.keeplive.service.RemoteService"
    android:process=":remote" />

免费获取更多安卓开发架构的资料（包括Fultter、高级UI、性能优化、架构师课程、 NDK、Kotlin、混合式开发（ReactNative+Weex）和一线互联网公司关于android面试的题目汇总可以加入【腾讯@安卓中高级进阶】