Work Manager未能按设置的初始延迟调度Work

Question

Work Manager未能按设置的初始延迟调度Work

5

所以我有一个工作程序，必须从预定时间的第二天开始运行。因此，如果工作在今晚8点激活，则需要在明天上午9点执行工作。因此，我使用OneTimeWorkRequest和setInitialDelay()。

以下是代码：

val currentTime = System.currentTimeMillis()
// calculate the timestamp for next dat 9AM 
val calendar = Calendar.getInstance()

calendar.set(Calendar.HOUR_OF_DAY, 9) 
calendar.set(Calendar.MINUTE, 0)
calendar.set(Calendar.SECOND, 0)
// next day
calendar.add(Calendar.DAY_OF_MONTH, 1)

val tomorrowTime = calendar.timeInMillis
val timeDiffBetweenNowAndTomorrow = tomorrowTime - currentTime

Timber.i("Tomorrow date is ${calendar.timeInMillis}")
Timber.i("Difference between now and tomorrow ${timeDiffBetweenNowAndTomorrow}")

val randomWorkRequest = OneTimeWorkRequestBuilder<RandomWallpaperWorker>()
                    .setInitialDelay(timeDiffBetweenNowAndTomorrow, TimeUnit.MILLISECONDS)
                    .build()

WorkManager.getInstance().enqueue(randomWorkRequest)

但我检查了一下，第二天早上我醒来时，工作并没有执行。为什么它没有被调度？我计算明天的时间戳的方式有问题吗？

- Sriram R

OneTimeWorkRequestBuilder<T> 是您自定义的类吗？您是否想要消除标准构建器，因为需要在参数中传递类类型？ - aminography

这只是与工作管理器依赖项一起提供的Kotlin快捷方式。您可以在结尾处添加“-ktx”以获得Kotlin友好的语法，并使用每个架构组件。 - Sriram R

干得好！ - aminography

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- aminography · Accepted Answer

正如我们在Google问题跟踪器中这里看到的：

不幸的是，一些设备将从“最近使用”菜单中终止应用程序视为强制停止。默认的Android操作系统不会这样做。当应用程序被强制停止时，它无法执行作业、接收警报或广播等操作。因此，我们无法解决这个问题——问题出在操作系统上，并且没有解决方法。

因此，您需要一个 Service 来保持您的应用程序活动状态。并且当该 Service 被终止（无论原因何在），它应该再次启动并初始化您的 worker，以确保其执行并保持 worker 任务的活动状态。以下是使用 STICKY IntentService 实现此想法的示例代码。

WallpaperService.kt

import android.app.IntentService
import android.app.Service
import android.content.Context
import android.content.Intent
import android.util.Log
import androidx.work.OneTimeWorkRequestBuilder
import androidx.work.WorkManager
import java.util.*
import java.util.concurrent.TimeUnit

class WallpaperService : IntentService("WallpaperService") {

    override fun onHandleIntent(intent: Intent?) {
        intent?.apply {
            when (intent.action) {
                ACTION_SETUP_WORKER -> {
                    setupWorker()
                }
            }
        }
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        super.onStartCommand(intent, flags, startId)
        // Define service as sticky so that it stays in background
        return Service.START_STICKY
    }

    private fun setupWorker() {
        val calendar = Calendar.getInstance()
        val currentTime = calendar.timeInMillis

        // for removing from recent apps test
        // calendar.add(Calendar.SECOND, 10)

        calendar.set(Calendar.HOUR_OF_DAY, 9)
        calendar.set(Calendar.MINUTE, 0)
        calendar.set(Calendar.SECOND, 0)
        calendar.set(Calendar.MILLISECOND, 0)
        calendar.add(Calendar.DAY_OF_MONTH, 1)

        val tomorrowTime = calendar.timeInMillis
        val timeDiffBetweenNowAndTomorrow = tomorrowTime - currentTime

        Log.i("WallpaperService", "************  Tomorrow date is ${calendar.timeInMillis}")
        Log.i("WallpaperService", "************  Difference between now and tomorrow $timeDiffBetweenNowAndTomorrow")

        val randomWorkRequest = OneTimeWorkRequestBuilder<RandomWallpaperWorker>()
            .setInitialDelay(timeDiffBetweenNowAndTomorrow, TimeUnit.MILLISECONDS)
            .build()
        WorkManager.getInstance().enqueue(randomWorkRequest)
    }

    companion object {

        const val ACTION_SETUP_WORKER = "ACTION_SETUP_WORKER"

        fun setupWorker(context: Context) {
            val intent = Intent(context, WallpaperService::class.java)
            intent.action = ACTION_SETUP_WORKER
            context.startService(intent)
        }
    }

}

RandomWallpaperWorker.kt

import android.content.Context
import android.util.Log
import androidx.work.Worker
import androidx.work.WorkerParameters

class RandomWallpaperWorker(val context: Context, params: WorkerParameters) : Worker(context, params) {

    override fun doWork(): Result {

        // Do what you want here...

        Log.e("RandomWallpaperWorker", "*****************  DONE!" )
        WallpaperService.setupWorker(context)
        return Result.SUCCESS
    }

}

MainActivity.kt

import android.os.Bundle
import android.support.v7.app.AppCompatActivity

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        WallpaperService.setupWorker(applicationContext)
    }

}

Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.aminography.workerapplication">

    <application ... >

        ...

        <service android:name=".WallpaperService" android:enabled="true"/>

    </application>

</manifest>