详解Android 8.0以上系统应用如何保活

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 = [e-mail](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)
      [e-mail](remoteservice)
      val intent = intent(this@localservice, remoteservice::class.java)
      [e-mail](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)
        [e-mail](13691, notification)
      }
    }
  }

  private val connection = object : serviceconnection {
    override fun onservicedisconnected(name: componentname) {
      val remoteservice = intent(this@remoteservice,
          localservice::class.java)
      [e-mail](remoteservice)
      [e-mail](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

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。