工作经理不使用setInitialDelay安排工作

Question

因此，我有一个工人，必须在第二天运行时，它的计划。因此，如果工作在今天晚上8点启动，那么我需要在第二天上午9点执行这项工作。所以我使用的是OneTimeWorkRequest和setInitialDelay()。

这是代码

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)

但是第二天醒来的时候，我检查了一下，结果工作没有执行。为什么没安排好呢？我计算第二天的时间戳有什么问题吗？

Answer 1

正如我们在Google的问题跟踪器中看到的这里：

不幸的是，一些设备在最近的菜单中将应用程序实现为强制停止。Android股票并不能做到这一点。当一个应用程序被强制停止时，它不能执行作业、接收警报或广播等等。因此，不幸的是，我们解决它是不可行的-问题在于操作系统，没有解决办法。

因此，您需要一个Service来维护您的应用程序。另外，当Service被终止时(不管原因是什么)，它应该重新启动并初始化您的工作人员，以确保它的执行并保持工作任务的存活。下面是使用STICKY IntentService实现这种想法的方法。

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>