当应用程序终止或关闭时，如何保留后台 android 服务运行

Question

大家好
我有新闻应用程序，我想在每次更新时推送通知。
我使用 socketIO 从服务器监听， Android 服务的问题我想在关闭时保持服务运行 |杀了。当应用运行和我在 onStartCommand START_STICKY_COMPATIBILITY 中 return 时，我已经开始我的服务它在应用程序关闭时正常工作，但小时服务被 OS 杀死但不会重新启动有帮助吗？

注意：我忽略了应用程序的电池优化

我的服务Class:

class ServicesMain: Service() {
    override fun onBind(p0: Intent?): IBinder? {
       return  null;
    }
    @SuppressLint("TrulyRandom")
    fun handleSSLHandshake() {
        try {
            val trustAllCerts = arrayOf<TrustManager>(object : X509TrustManager {
                override fun getAcceptedIssuers(): Array<X509Certificate>? {
                    return null;
                }

                override fun checkClientTrusted(certs: Array<X509Certificate>, authType: String) {}
                override fun checkServerTrusted(certs: Array<X509Certificate>, authType: String) {}
            })
            val sc = SSLContext.getInstance("SSL")
            sc.init(null, trustAllCerts, SecureRandom())
            HttpsURLConnection.setDefaultSSLSocketFactory(sc.socketFactory)
            HttpsURLConnection.setDefaultHostnameVerifier { arg0, arg1 -> true }
        } catch (ignored: Exception) {
        }
    }
@RequiresApi(Build.VERSION_CODES.O)
fun  startSocket(){
    handleSSLHandshake()
    runBroadcast()
    Log.d("TAG", "BroadcastReceiver: ")
    Timer().schedule(object : TimerTask() {
        override fun run() {
            Log.d("TAG", "run: ${socket!!.connected()} ")

        }

    }, 0, 10000)



}
    private var socket: Socket? = null;

    @SuppressLint("RestrictedApi")
    @RequiresApi(Build.VERSION_CODES.O)
    fun runBroadcast() {
        val myHostnameVerifier = HostnameVerifier { _, _ ->
            return@HostnameVerifier true
        }

        val trustAllCerts = arrayOf<TrustManager>(object : X509TrustManager {
            override fun checkClientTrusted(chain: Array<X509Certificate>, authType: String) {}

            override fun checkServerTrusted(chain: Array<X509Certificate>, authType: String) {}

            override fun getAcceptedIssuers(): Array<X509Certificate> {
                return arrayOf()
            }
        })

        val sslContext = SSLContext.getInstance("TLS")
        sslContext.init(null, trustAllCerts, null)

        val okHttpClient = OkHttpClient.Builder()
                .hostnameVerifier(myHostnameVerifier)
                .sslSocketFactory(sslContext.socketFactory, trustAllCerts[0] as X509TrustManager)
                .readTimeout(0, TimeUnit.MILLISECONDS).writeTimeout(0, TimeUnit.MILLISECONDS).build()

        val options = IO.Options()
        options.transports = arrayOf(Polling.NAME)
        options.webSocketFactory = okHttpClient
        options.callFactory=okHttpClient
        options.secure = true
        socket = IO.socket("https://....", options);

        socket!!.connect().on("message", Emitter.Listener { args ->


            val jsonObject = JSONObject(args[0] as String)

            val calendarTime = jsonObject.getLong("starttime") - (Calendar.getInstance().timeInMillis)

            println(calendarTime)

            val builder = Constraints.Builder()
                    .setRequiredNetworkType(NetworkType.CONNECTED)
            val data: Data.Builder = Data.Builder()
            data.putStringArray("data", arrayOf<String>(jsonObject.getString("title"), jsonObject.getString("subject"), jsonObject.getString("id")))


            val oneTimeWorkRequest = OneTimeWorkRequest.Builder(NotificationEvetns::class.java).setInputData(data.build()).setConstraints(builder.build())
                    .setInitialDelay(calendarTime, TimeUnit.MILLISECONDS).addTag(jsonObject.getString("id")).build()
            this.let { WorkManager.getInstance(it).enqueue(oneTimeWorkRequest) }
        })


}

    override fun onTaskRemoved(rootIntent: Intent?) {

        super.onTaskRemoved(rootIntent)
        Log.d("TAG", "onTaskRemoved: ")
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        Log.d("TAG", "onStartCommand: ")

        return  START_STICKY_COMPATIBILITY
    }




    @RequiresApi(Build.VERSION_CODES.O)
    override fun onCreate() {
        super.onCreate()

        startSocket()
    }


    override fun onDestroy() {
        super.onDestroy()
        socket?.disconnect()
    }

    override fun onTrimMemory(level: Int) {
        super.onTrimMemory(level)
        Log.d("TAG", "onTrimMemory: ")
    }

}

Answer 1

你不能，在 Android 的现代版本上不行。您可以创建一个最不可能被杀死的前台服务（在前台应用程序之外），但您不能指望它不会被杀死。而是编写您的代码，以便它不需要 - 主要是通过使用 WorkManager 来触发后台工作。除非你正在写一个服务器，在这种情况下我会说你应该使用另一个 OS，Android 是不合适的。

对于来自您提到的服务器的消息，我会使用 FCM 推送消息而不是长期的直接服务器连接。

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