简单学习

首先导入库

implementation "android.arch.work:work-runtime-ktx:1.0.0-alpha01"

然后简单操作,因为还没看别人咋写的，就知道有这个类，就看提示有啥方法开始操作
简单写了3个worker，就是延迟在一个文件里写下当前时间而已。

    fun startWork() {
        var constraint = Constraints.Builder().setRequiredNetworkType(NetworkType.CONNECTED).build()
        var inputData = Data.Builder().putString("title", "title1").build()

        var reques = OneTimeWorkRequest.Builder(MyWorker::class.java).setInitialDelay(20, TimeUnit.SECONDS).addTag("work1").setConstraints(constraint).build()
        var reques2 = OneTimeWorkRequest.Builder(MyWorker::class.java).setInitialDelay(50, TimeUnit.SECONDS).addTag("work2").setInputData(inputData).build()
        var reques3 = OneTimeWorkRequest.Builder(MyWorker::class.java).setInitialDelay(50, TimeUnit.SECONDS).addTag("work3").build()
        WorkManager.getInstance().beginWith(reques, reques2).then(reques3).enqueue()
    }

    fun getStatus() {
        WorkManager.getInstance().getStatusesByTag("work1")?.observeForever(object :android.arch.lifecycle.Observer<MutableList<WorkStatus>> {
            override fun onChanged(t: MutableList<WorkStatus>?) {
                println("00=================${t?.size}")
                (0 until (t?.size?:0)).forEach {
                    var workstaus = t!![it]
                    println("${it}==============${workstaus.id}====${workstaus.state}//${workstaus.state.isFinished}==${workstaus.tags}")
                }
            }
        })
        println("111===========${WorkManager.getInstance().getStatusesByTag("work2")}====${WorkManager.getInstance().getStatusesByTag("work2")?.value?.size}")
    }

    public class MyWorker : Worker() {
        var formate = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.CHINA)
        override fun doWork(): WorkerResult {
            var smg = formate.format(Date(System.currentTimeMillis()))
            inputData.apply {
                smg = this.getString("title", "") +"  "+ smg
            }
            UtilNormal.saveWords(smg) //就是把这个字符串写入sdcard的文件。
            return WorkerResult.SUCCESS
        }
    }

补充

Constraints.Builder().setRequiresCharging(false) 这个boolean值的作用，如果设置为true，那么必须插上电源这个任务才会运行。 这里插上电源，我试了下，必须是交流电。用数据线连接到电脑上的不算。
begin(a).then(b)的效果，a执行完，并且dowork（）返回WorkerResult.SUCCESS ，b才会执行。
如果a返回了FAILED,那么b不会执行的，如果a返回retry，那么a就会等待时机再次尝试，直到返回成功，b才会执行。

测试中发现。点开start以后，我就打开应用程序，点了强制停止，然后发现过了一会它又成了运行状态了【强制停止不是灰色的，又可以点击了】
而且studio的日志里看到下边的东西

22:44:17.247 : Failed execv(/system/bin/dex2oat --runtime-arg -classpath --runtime-arg  --debuggable --instruction-set=arm --instruction-set-features=smp,-div,-atomic_ldrd_strd --runtime-arg -Xrelocate --boot-image=/system/framework/boot.art --runtime-arg -Xms64m --runtime-arg -Xmx512m --instruction-set-variant=cortex-a53 --instruction-set-features=default --dex-file=/data/app/com.charliesong.demo0327-1/split_lib_dependencies_apk.apk --oat-file=/data/dalvik-cache/arm/data@app@com.charliesong.demo0327-1@split_lib_dependencies_apk.apk@classes.dex) because non-0 exit status

22:44:18.887 D/PackageManagerHelper: androidx.work.impl.background.systemjob.SystemJobService enabled
22:44:18.887  D/Schedulers: Created SystemJobScheduler and enabled SystemJobService
22:44:18.897  D/PackageManagerHelper: androidx.work.impl.background.firebase.FirebaseJobService could not be disabled
    java.lang.IllegalArgumentException: Component class androidx.work.impl.background.firebase.FirebaseJobService does not exist in com.charliesong.demo0327

22:44:18.897  D/PackageManagerHelper: androidx.work.impl.background.systemalarm.SystemAlarmService disabled
22:44:18.907  I/InstantRun: starting instant run server: is main process
22:44:18.907  D/ForceStopRunnable: Application was force-stopped, rescheduling.
22:44:18.987 D/SystemJobService: onStartJob for c4d275cb-10af-4c08-bc9b-0985f196cbd9
22:44:18.987  D/SystemJobScheduler: Scheduling work ID c4d275cb-10af-4c08-bc9b-0985f196cbd9 Job ID 40
22:44:18.987  D/SystemJobService: Job is already being executed by SystemJobService: c4d275cb-10af-4c08-bc9b-0985f196cbd9
22:44:18.997  D/SystemJobScheduler: Scheduling work ID c4d275cb-10af-4c08-bc9b-0985f196cbd9 Job ID 41
22:44:18.997  D/SystemJobScheduler: Scheduling work ID ce1865ad-3d30-4e0d-8474-f6d64307a973 Job ID 42
22:44:18.997 /SystemJobScheduler: Scheduling work ID ce1865ad-3d30-4e0d-8474-f6d64307a973 Job ID 43
22:44:18.997  D/Processor: Processor: processing c4d275cb-10af-4c08-bc9b-0985f196cbd9
22:44:19.017 D/WorkerWrapper: Worker result SUCCESS for c4d275cb-10af-4c08-bc9b-0985f196cbd9
22:44:19.027  D/Processor: Processor c4d275cb-10af-4c08-bc9b-0985f196cbd9 executed; isSuccessful = true, reschedule = false
22:44:19.027 D/SystemJobService: c4d275cb-10af-4c08-bc9b-0985f196cbd9 executed on JobScheduler
22:44:19.027 /SystemJobScheduler: Scheduling work ID ce1865ad-3d30-4e0d-8474-f6d64307a973 Job ID 44
22:44:19.037 /SystemJobScheduler: Scheduling work ID ce1865ad-3d30-4e0d-8474-f6d64307a973 Job ID 45
22:44:39.017 /SystemJobService: onStartJob for c4d275cb-10af-4c08-bc9b-0985f196cbd9
22:44:39.017 /SystemJobService: Job is already being executed by SystemJobService: c4d275cb-10af-4c08-bc9b-0985f196cbd9
22:44:39.017 /Processor: Processor: processing c4d275cb-10af-4c08-bc9b-0985f196cbd9
22:44:39.027 com.charliesong.demo0327 E/WorkerWrapper: Status for c4d275cb-10af-4c08-bc9b-0985f196cbd9 is SUCCEEDED; not doing any work
22:44:39.027 /Processor: Processor c4d275cb-10af-4c08-bc9b-0985f196cbd9 executed; isSuccessful = false, reschedule = false
22:44:39.027 /SystemJobService: c4d275cb-10af-4c08-bc9b-0985f196cbd9 executed on JobScheduler
22:44:48.087 /SystemJobService: onStartJob for ce1865ad-3d30-4e0d-8474-f6d64307a973
22:44:48.087 /Processor: Processor: processing ce1865ad-3d30-4e0d-8474-f6d64307a973
22:44:48.087 /SystemJobService: Job is already being executed by SystemJobService: ce1865ad-3d30-4e0d-8474-f6d64307a973
22:44:48.107 /WorkerWrapper: Worker result SUCCESS for ce1865ad-3d30-4e0d-8474-f6d64307a973
22:44:48.117 /WorkerWrapper: Setting status to enqueued for 95339398-f24f-439f-aab0-3dfbbe787d45
22:44:48.117 /Processor: Processor ce1865ad-3d30-4e0d-8474-f6d64307a973 executed; isSuccessful = true, reschedule = false
22:44:48.117 /SystemJobService: ce1865ad-3d30-4e0d-8474-f6d64307a973 executed on JobScheduler
22:44:48.127 /SystemJobScheduler: Scheduling work ID 95339398-f24f-439f-aab0-3dfbbe787d45 Job ID 46
22:44:48.127 /SystemJobScheduler: Scheduling work ID 95339398-f24f-439f-aab0-3dfbbe787d45 Job ID 47
22:45:09.017 /SystemJobService: onStartJob for ce1865ad-3d30-4e0d-8474-f6d64307a973
22:45:09.017 /Processor: Processor: processing ce1865ad-3d30-4e0d-8474-f6d64307a973
22:45:09.017 /SystemJobService: Job is already being executed by SystemJobService: ce1865ad-3d30-4e0d-8474-f6d64307a973
22:45:09.027 com.charliesong.demo0327 E/WorkerWrapper: Status for ce1865ad-3d30-4e0d-8474-f6d64307a973 is SUCCEEDED; not doing any work
22:45:09.027 /Processor: Processor ce1865ad-3d30-4e0d-8474-f6d64307a973 executed; isSuccessful = false, reschedule = false
22:45:09.027 /SystemJobService: ce1865ad-3d30-4e0d-8474-f6d64307a973 executed on JobScheduler
22:45:10.017 /SystemJobService: onStartJob for ce1865ad-3d30-4e0d-8474-f6d64307a973
22:45:10.017 /Processor: Processor: processing ce1865ad-3d30-4e0d-8474-f6d64307a973
22:45:10.017 /SystemJobService: Job is already being executed by SystemJobService: ce1865ad-3d30-4e0d-8474-f6d64307a973
22:45:10.027 com.charliesong.demo0327 E/WorkerWrapper: Status for ce1865ad-3d30-4e0d-8474-f6d64307a973 is SUCCEEDED; not doing any work
22:45:10.027 /Processor: Processor ce1865ad-3d30-4e0d-8474-f6d64307a973 executed; isSuccessful = false, reschedule = false
22:45:10.027 /SystemJobService: ce1865ad-3d30-4e0d-8474-f6d64307a973 executed on JobScheduler
22:45:58.907 /SystemJobService: onStartJob for 95339398-f24f-439f-aab0-3dfbbe787d45
22:45:58.907 /Processor: Processor: processing 95339398-f24f-439f-aab0-3dfbbe787d45
22:45:58.917 /SystemJobService: Job is already being executed by SystemJobService: 95339398-f24f-439f-aab0-3dfbbe787d45
22:45:58.927 /WorkerWrapper: Worker result SUCCESS for 95339398-f24f-439f-aab0-3dfbbe787d45
22:45:58.927 /Processor: Processor 95339398-f24f-439f-aab0-3dfbbe787d45 executed; isSuccessful = true, reschedule = false
22:45:58.927 /SystemJobService: 95339398-f24f-439f-aab0-3dfbbe787d45 executed on JobScheduler

另外当start执行了N次以后，可以看到get到的也是N次的信息,除非卸载重装，否则start了n次tag为xxx的work，到时候getbytag就能获取N次

06-10 22:53:50.047 com.charliesong.demo0327 I/System.out: 0==============2140871e-f14a-498e-bc41-e6728b91a7ae====SUCCEEDED//true==[work1]
06-10 22:53:50.047 com.charliesong.demo0327 I/System.out: 1==============85ed6feb-b5d2-4c5b-a3c6-c005ea60054e====SUCCEEDED//true==[work1]
06-10 22:53:50.047 com.charliesong.demo0327 I/System.out: 2==============87b3b5d9-000d-4ef2-ba7e-2c005fc29da8====SUCCEEDED//true==[work1]
06-10 22:53:50.047 com.charliesong.demo0327 I/System.out: 3==============c4d275cb-10af-4c08-bc9b-0985f196cbd9====SUCCEEDED//true==[work1]

不过有点奇怪的是，我start里就有3个任务，可每次都有4条日志,前2条的work ID是一样的，就是job ID 不一样，不懂。

06-10 22:59:49.737 xxx D/SystemJobScheduler: Scheduling work ID bbef65fb-aca0-4b8f-96a1-50da7234e5c8 Job ID 8
06-10 22:59:49.737 xxx D/SystemJobScheduler: Scheduling work ID bbef65fb-aca0-4b8f-96a1-50da7234e5c8 Job ID 9
06-10 22:59:49.737 xxxx D/SystemJobScheduler: Scheduling work ID cb3f7b83-9b8b-4e8d-aeb3-915d2498ff3f Job ID 10
06-10 22:59:49.737 xxx D/SystemJobScheduler: Scheduling work ID cb3f7b83-9b8b-4e8d-aeb3-915d2498ff3f Job ID 11

测试

卸载重装app，然后开启一个任务

        val oneTimeRequest= OneTimeWorkRequestBuilder<Worker2>().setConstraints(constraints).setInputData(data)
                .addTag("worker2")
                .build()

        WorkManager.getInstance().beginWith(oneTimeRequest).enqueue()

     class Worker2:Worker() {
        override fun doWork(): WorkerResult {
            println("start ${javaClass.simpleName}==================")
            Thread.sleep(3000)
            println("end ${javaClass.simpleName}================")
            val date=SimpleDateFormat("yyyyMMDD_HHmmss", Locale.getDefault()).format(Date())
            UtilFile.saveStringToTempFile("$date ${javaClass.simpleName}  ${inputData.getString("title","")} \r\n")
            return  WorkerResult.SUCCESS
        }
    }

日志

21:18:45.793  D/SystemJobScheduler: Scheduling work ID 17d724d0-757e-44e3-8814-1b7a933a3f46 Job ID 0
21:18:45.793  D/SystemJobScheduler: Scheduling work ID 17d724d0-757e-44e3-8814-1b7a933a3f46 Job ID 1
21:18:45.793  D/GreedyScheduler: Starting tracking for 17d724d0-757e-44e3-8814-1b7a933a3f46
D/ConstraintTracker: NetworkStateTracker: initial state = [ Connected=true Validated=true Metered=false NotRoaming=true ]
21:18:45.803  D/NetworkStateTracker: Registering broadcast receiver
21:18:45.803  D/WorkConstraintsTracker: Constraints met for 17d724d0-757e-44e3-8814-1b7a933a3f46
21:18:45.803  D/GreedyScheduler: Constraints met: Scheduling work ID 17d724d0-757e-44e3-8814-1b7a933a3f46
21:18:45.803  D/WorkConstraintsTracker: Constraints met for 17d724d0-757e-44e3-8814-1b7a933a3f46
21:18:45.803  D/GreedyScheduler: Constraints met: Scheduling work ID 17d724d0-757e-44e3-8814-1b7a933a3f46
21:18:45.813  D/Processor: Processor: processing 17d724d0-757e-44e3-8814-1b7a933a3f46
21:18:45.813  D/Processor: Work 17d724d0-757e-44e3-8814-1b7a933a3f46 is already enqueued for processing
I/System.out: start Worker2==================
21:18:45.873  D/ViewRootImpl: MSG_RESIZED_REPORT: ci=Rect(0, 24 - 0, 0) vi=Rect(0, 0 - 0, 0) or=2
21:18:45.883  D/NetworkStateTracker: Network broadcast received
21:18:45.923  I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@caf4359 time:15813324
21:18:46.803  D/SystemJobService: onStartJob for 17d724d0-757e-44e3-8814-1b7a933a3f46
21:18:46.803  D/Processor: Work 17d724d0-757e-44e3-8814-1b7a933a3f46 is already enqueued for processing
21:18:46.803  D/SystemJobService: Job is already being executed by SystemJobService: 17d724d0-757e-44e3-8814-1b7a933a3f46
21:18:48.843  I/System.out: end Worker2================
21:18:48.843  D/WorkerWrapper: Worker result SUCCESS for 17d724d0-757e-44e3-8814-1b7a933a3f46
21:18:48.853  D/Processor: Processor 17d724d0-757e-44e3-8814-1b7a933a3f46 executed; isSuccessful = true, reschedule = false
21:18:48.853  D/SystemJobService: 17d724d0-757e-44e3-8814-1b7a933a3f46 executed on JobScheduler

间隔时间重复执行某个work

看文章发现有个PeriodicWorkRequest可以执行重复的任务，试了下结果发现没重复啊，后来点击源码才看到，这玩意默认的最小间隔是15分钟。

    fun startRepeateWork(){
        var request=PeriodicWorkRequest.Builder(MyWorker::class.java,1,TimeUnit.MINUTES).addTag("hello").build()
        WorkManager.getInstance().enqueue(request)
        UtilNormal.saveUUID(this,request.id.toString())
    }

    fun getRepeatWorkStatus(){
        var str=UtilNormal.getUUID(this)
        if(TextUtils.isEmpty(str)){
            return
        }
        WorkManager.getInstance().getStatusById(UUID.fromString(str))?.apply {
            this.removeObserver(observerOnly)
            this.observeForever(observerOnly)
        }
    }

    val observerOnly=object:Observer<WorkStatus>{
        override fun onChanged(t: WorkStatus?) {
            t?.apply {
                println("onChanged==============${t.id}====${t.state}//${t.state.isFinished}==${t.tags}")
            }
        }
    }