如何保存上次执行后台进程时的日期和时间

Question

当检测到新邮件时，我的应用程序检查收到的新电子邮件，发送通知。目前，我一直在检查邮件是否在过去30分钟内收到，以显示邮件，但WorkManager有时会在后台停止工作(如果您知道为什么请告诉我，是安卓以某种方式杀死了进程，还是我的配置不好？)还会错过邮件通知。不知何故，我需要保存上次通知显示时的数据和时间(执行后台进程)，但当WorkManager由于某种原因而停止工作时，我不知道如何将数据保存在WorkManager中。

WorkManager调用功能：

  @SuppressLint("RestrictedApi")
private fun startWorker(email: String, password: String) {

    if (enableMailNotifications == 1) {


        val constraints = Constraints.Builder()
            .setRequiredNetworkType(NetworkType.CONNECTED).build()

        val data = Data.Builder()
        data.put("email", email)
        data.put("password", password)


        val build: PeriodicWorkRequest = PeriodicWorkRequest.Builder(
            WorkerMan::class.java,
            15,
            TimeUnit.MINUTES,
            15,
            TimeUnit.MINUTES,

            )

            .addTag("WorkManager")
            .setInputData(data.build())
            .setConstraints(constraints)
            .build()

        WorkManager.getInstance(this)
            .enqueueUniquePeriodicWork("WorkManager", ExistingPeriodicWorkPolicy.REPLACE, build)
    }else{
        println("WorkManager not called: Mail Notifications are turned off")
    }
}

WorkManager类：

class WorkerMan(private val mContext: Context, workerParameters: WorkerParameters) :
    Worker(mContext, workerParameters) {


    @SuppressLint("RestrictedApi", "CheckResult")
    val email = inputData.getString("email")
    val password = inputData.getString("password")

    @SuppressLint("RestrictedApi")
    override fun doWork(): Result {


        println("WorkManager: Work called")
        Thread.sleep(5000)


        val session = Session.getDefaultInstance(Properties())
        val store = session.getStore("imaps")
        store.connect(
            "*****************",
            993,
            email,
            password
        )
        val inbox = store.getFolder("INBOX")
        inbox.open(Folder.READ_ONLY)


        val messages = inbox.search(
            FlagTerm(Flags(Flags.Flag.SEEN), false)
        )


        Arrays.sort(
            messages
        ) { m1: Message, m2: Message ->
            try {
                return@sort m2.sentDate.compareTo(m1.sentDate)
            } catch (e: MessagingException) {
                throw RuntimeException(e)
            }
        }





        Thread.sleep(1000)
        println("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ")
        println("WorkManager Started")
        println("WorkMananager email: " + email)
        val current = LocalTime.now()
        println("WorkMananager time: " + current)
        println("Messages amount: " + messages.size)
        println("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ")

        for (message in messages) {


            if (message.receivedDate.toInstant() >= Instant.now().minusMillis(1000 * 33 * 60)) {


                Thread.sleep(3000)
                println("=====================================================")
                println("NOTIFIKACIJA")

                var title = ""
                for (element in message.from) {
                    title += element.toString().substringAfter("<").substringBefore(">")
                    title += " "
                }
                println("Title :" + title)
                println("Subject :" + message.subject)
                println("Datum i vreme : " + message.receivedDate)

                title.replace("[", "")
                title.replace("]", "")



                FirebaseMessaging.getInstance().token.addOnSuccessListener { token: String ->
                    if (!TextUtils.isEmpty(token)) {
                        Log.d("TAG", "retrieve token successful : $token")
                        try {
                            send(token, message.subject, title)
                        } catch (e: MessagingException) {
                            e.printStackTrace()
                        }
                    } else {
                        Log.w("TAG", "token should not be null...")
                    }
                }.addOnFailureListener { e: Exception? -> }.addOnCanceledListener {}
                    .addOnCompleteListener { task: Task<String> ->
                        Log.v(
                            "TAG",
                            "This is the token : " + task.result
                        )
                    }


//
            }


        }
        println("=====================================================")
        Log.d("WorkManager", "Job finished")

        return Result.Success();
    }

}


fun send(to: String?, body: String?, title: String?): String? {
    try {
        val apiKey =
            "*******************************************"
        val url = URL("https://fcm.googleapis.com/fcm/send")
        val conn = url.openConnection() as HttpURLConnection
        conn.doOutput = true
        conn.requestMethod = "POST"
        conn.setRequestProperty("Content-Type", "application/json")
        conn.setRequestProperty("Authorization", "key=$apiKey")
        conn.doOutput = true
        val message = JSONObject()
        message.put("to", to)
        message.put("priority", "high")
        val notification = JSONObject()
        notification.put("title", title)
        notification.put("body", body)
        message.put("notification", notification)
        val os = conn.outputStream
        os.write(message.toString().toByteArray())
        os.flush()
        os.close()
        val responseCode = conn.responseCode
        println("\nSending 'POST' request to URL : $url")
        println("Post parameters : $message")
        println("Response Code : $responseCode")
        println("Response Code : " + conn.responseMessage)
        val `in` = BufferedReader(InputStreamReader(conn.inputStream))
        var inputLine: String?
        val response = StringBuffer()
        while (`in`.readLine().also { inputLine = it } != null) {
            response.append(inputLine)
        }
        `in`.close()

        // print result
        println(response.toString())
        return response.toString()
    } catch (e: Exception) {
        e.printStackTrace()
    }
    return "error"
}

Answer 1

我看到了很多线程：：doWork方法中的睡眠调用。doWork执行会占用您多长时间？

您应该注意，它有一个限制- 10分钟，从java文档：

给工作人员最多十分钟的时间来完成其执行并返回{@link androidx.work.ListenableWorker.Result}。在这段时间结束后，工人将被通知停止工作。

此外，在没有开始工作的情况下，可能会发生以下情况：

当工作的所有先决条件都完成时，它就有资格执行。如果其中任何一个先决条件失败或被取消，工作将永远不会运行。

所以也许你的案子还没开始呢？

关于保存时间戳，您可以将其保存到永久存储，如数据库或共享偏好。