我当前的Android应用程序使用的是>
archWorkerRuntimeVersion = '2.3.0-beta02' api "androidx.work:work-runtime:$archWorkerRuntimeVersion" api "androidx.work:work-runtime-ktx:$archWorkerRuntimeVersion"我正在通过LiveData观察工人状态，如下所示：-
WorkManager.getInstance(applicationContext).getWorkInfoByIdLiveData(experimentRequest.id).observe(lifeCycleOwner, observer)其中lifeCycleOwner是我的Activity，而观察者是静态val
private val observer = object : Observer<WorkInfo> { override fun onChanged(it: WorkInfo?) { Log.e("Worker", "this is our single observer $it $this") if (it == null) return repository.storeCurrentWorkId(it.id) } }
observe(lifeCycleOwner, observer)的注释指出：-
/** * Adds the given observer to the observers list within the lifespan of the given * owner. The events are dispatched on the main thread. If LiveData already has data * set, it will be delivered to the observer. * <p> * The observer will only receive events if the owner is in {@link Lifecycle.State#STARTED} * or {@link Lifecycle.State#RESUMED} state (active). * <p> * If the owner moves to the {@link Lifecycle.State#DESTROYED} state, the observer will * automatically be removed. * <p> * When data changes while the {@code owner} is not active, it will not receive any updates. * If it becomes active again, it will receive the last available data automatically. * <p> * LiveData keeps a strong reference to the observer and the owner as long as the * given LifecycleOwner is not destroyed. When it is destroyed, LiveData removes references to * the observer & the owner. * <p> * If the given owner is already in {@link Lifecycle.State#DESTROYED} state, LiveData * ignores the call. * <p> * If the given owner, observer tuple is already in the list, the call is ignored. * If the observer is already in the list with another owner, LiveData throws an * {@link IllegalArgumentException}. * * @param owner The LifecycleOwner which controls the observer * @param observer The observer that will receive the events */尽管此陈述似乎并不成立
If it becomes active again, it will receive the last available data automatically.除非我误解了它的含义。
我指的是，当我的活动再次活跃时，我将收到最新（最后）的可用数据。
从我的测试来看并非如此，我收到的唯一数据是在我的活动再次变为活动后发送的任何新数据。
我在做什么错？
我的活动开始后，有什么方法可以接收最新数据？
更新
我创建了以下简单的Android应用程序来展示此问题。
此Android应用包含三个活动。
Dummy Main Activity Worker Activity Dummy Second Activity我的测试涉及
1). Starting App with Dummy Main Activity, navigating to WorkerActivity, starting Worker and waiting for the worker to SUCCEED 2). Starting App with Dummy Main Activity, navigating to WorkerActivity, starting Worker, then navigate to Dummy Second Activity and returning to WorkerActivity 3). Starting App with Dummy Main Activity, navigating to WorkerActivity, starting Worker, then return to Dummy Main Activity and returning to WorkerActivity工作者活动开始，并观察LiveData，如下所示
class WorkerActivity : AppCompatActivity(), Observer<WorkInfo?> { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_ninth) findViewById<Button>(R.id.start_work_tags_button).setOnClickListener { doSomeWork() } findViewById<Button>(R.id.start_work_button).setOnClickListener { startActivity(Intent(this@WorkerActivity, Seventh::class.java)) } } private fun doSomeWork() { val ninthRequest: OneTimeWorkRequest = manufactureOneTimeWorkRequest(NinthWorker::class.java) WorkManager.getInstance(applicationContext) .beginUniqueWork(UNIQUE_WORK_NAME, ExistingWorkPolicy.KEEP, ninthRequest) .enqueue() val workInfos = WorkManager.getInstance(applicationContext).getWorkInfoByIdLiveData(ninthRequest.id) workInfos.observe(this as LifecycleOwner, this as Observer<in WorkInfo>) } private fun manufactureOneTimeWorkRequest(klazz: Class<out CoroutineWorker>): OneTimeWorkRequest { return OneTimeWorkRequest.Builder(klazz).addTag(WORK_IN_PROGRESS_TAG + "${UUID.randomUUID()}").build() } companion object { private const val WORK_IN_PROGRESS_TAG = "SYNC-IN-PROGRESS-TAG" private const val UNIQUE_WORK_NAME = "SYNC-UNIQUE_WORK_NAME" } override fun onChanged(workInfo: WorkInfo?) { Log.e("NINTH", "onChanged($workInfo)") } }使用两个“虚拟”活动来使
WorkerActivity作为LifeCycle所有者成为“活动中”
我在测试1中看到的日志）。显示在这里：-
2020-01-14 10:54:36.114 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityCreated() org.vulgaris.behave.sixth.DummyMainActivity@cdc2743 2020-01-14 10:54:36.228 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStarted() org.vulgaris.behave.sixth.DummyMainActivity@cdc2743 2020-01-14 10:54:36.230 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityResumed() org.vulgaris.behave.sixth.DummyMainActivity@cdc2743 2020-01-14 10:54:43.324 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityPaused() org.vulgaris.behave.sixth.DummyMainActivity@cdc2743 2020-01-14 10:54:43.343 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityCreated() org.vulgaris.behave.ninth.WorkerActivity@abd837d 2020-01-14 10:54:43.386 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStarted() org.vulgaris.behave.ninth.WorkerActivity@abd837d 2020-01-14 10:54:43.387 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityResumed() org.vulgaris.behave.ninth.WorkerActivity@abd837d 2020-01-14 10:54:43.776 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStopped() org.vulgaris.behave.sixth.DummyMainActivity@cdc2743 2020-01-14 10:54:43.778 23452-23452/org.vulgaris.behave E/APPLICATION: onActivitySaveInstanceState() org.vulgaris.behave.sixth.DummyMainActivity@cdc2743 2020-01-14 10:54:48.812 23452-23452/org.vulgaris.behave E/WorkerActivity: onChanged(WorkInfo{mId='f3655bdd-3b1d-4e59-a896-3798ec860856', mState=ENQUEUED, mOutputData=Data {}, mTags=[org.vulgaris.behave.worker.NinthWorker, SYNC-IN-PROGRESS-TAG691b47cb-143f-42fc-8d88-903880e1f699], mProgress=Data {}}) 2020-01-14 10:54:48.826 23452-23584/org.vulgaris.behave E/NinthWorker: doWork 56fd9de0-ad8e-4275-b8a0-28e0cd045b9c inputData = Data {} 2020-01-14 10:54:48.829 23452-23452/org.vulgaris.behave E/WorkerActivity: onChanged(WorkInfo{mId='f3655bdd-3b1d-4e59-a896-3798ec860856', mState=RUNNING, mOutputData=Data {}, mTags=[org.vulgaris.behave.worker.NinthWorker, SYNC-IN-PROGRESS-TAG691b47cb-143f-42fc-8d88-903880e1f699], mProgress=Data {}}) 2020-01-14 10:55:48.851 23452-23583/org.vulgaris.behave I/WM-WorkerWrapper: Worker result SUCCESS for Work [ id=f3655bdd-3b1d-4e59-a896-3798ec860856, tags={ org.vulgaris.behave.worker.NinthWorker, SYNC-IN-PROGRESS-TAG691b47cb-143f-42fc-8d88-903880e1f699 } ] 2020-01-14 10:55:48.902 23452-23452/org.vulgaris.behave E/WorkerActivity: onChanged(WorkInfo{mId='f3655bdd-3b1d-4e59-a896-3798ec860856', mState=SUCCEEDED, mOutputData=Data {}, mTags=[org.vulgaris.behave.worker.NinthWorker, SYNC-IN-PROGRESS-TAG691b47cb-143f-42fc-8d88-903880e1f699], mProgress=Data {}})我在测试2中看到的日志）。显示在这里：-
2020-01-14 10:59:20.726 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityCreated() org.vulgaris.behave.sixth.DummyMainActivity@6a03dee 2020-01-14 10:59:20.780 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStarted() org.vulgaris.behave.sixth.DummyMainActivity@6a03dee 2020-01-14 10:59:20.781 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityResumed() org.vulgaris.behave.sixth.DummyMainActivity@6a03dee 2020-01-14 10:59:23.781 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityPaused() org.vulgaris.behave.sixth.DummyMainActivity@6a03dee 2020-01-14 10:59:23.799 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityCreated() org.vulgaris.behave.ninth.WorkerActivity@2fe5636 2020-01-14 10:59:23.836 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStarted() org.vulgaris.behave.ninth.WorkerActivity@2fe5636 2020-01-14 10:59:23.837 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityResumed() org.vulgaris.behave.ninth.WorkerActivity@2fe5636 2020-01-14 10:59:24.209 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStopped() org.vulgaris.behave.sixth.DummyMainActivity@6a03dee 2020-01-14 10:59:24.210 23452-23452/org.vulgaris.behave E/APPLICATION: onActivitySaveInstanceState() org.vulgaris.behave.sixth.DummyMainActivity@6a03dee 2020-01-14 10:59:30.564 23452-23452/org.vulgaris.behave E/WorkerActivity: onChanged(WorkInfo{mId='da800c85-485d-4cb5-9931-d3f20edf611e', mState=ENQUEUED, mOutputData=Data {}, mTags=[SYNC-IN-PROGRESS-TAG6c6ff5e2-b8a7-4f73-99e6-c112f7598287, org.vulgaris.behave.worker.NinthWorker], mProgress=Data {}}) 2020-01-14 10:59:30.585 23452-23452/org.vulgaris.behave E/WorkerActivity: onChanged(WorkInfo{mId='da800c85-485d-4cb5-9931-d3f20edf611e', mState=RUNNING, mOutputData=Data {}, mTags=[SYNC-IN-PROGRESS-TAG6c6ff5e2-b8a7-4f73-99e6-c112f7598287, org.vulgaris.behave.worker.NinthWorker], mProgress=Data {}}) 2020-01-14 10:59:30.585 23452-23585/org.vulgaris.behave E/NinthWorker: doWork 6407357d-0471-41ee-8ea2-6cedeaf1e463 inputData = Data {} 2020-01-14 10:59:31.749 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityPaused() org.vulgaris.behave.ninth.WorkerActivity@2fe5636 2020-01-14 10:59:31.767 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityCreated() org.vulgaris.behave.seventh.DummySecondActivity@3572f3a 2020-01-14 10:59:31.834 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStarted() org.vulgaris.behave.seventh.DummySecondActivity@3572f3a 2020-01-14 10:59:31.835 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityResumed() org.vulgaris.behave.seventh.DummySecondActivity@3572f3a 2020-01-14 10:59:32.211 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStopped() org.vulgaris.behave.ninth.WorkerActivity@2fe5636 2020-01-14 10:59:32.211 23452-23452/org.vulgaris.behave E/APPLICATION: onActivitySaveInstanceState() org.vulgaris.behave.ninth.WorkerActivity@2fe5636 2020-01-14 10:59:33.112 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityPaused() org.vulgaris.behave.seventh.DummySecondActivity@3572f3a 2020-01-14 10:59:33.128 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStarted() org.vulgaris.behave.ninth.WorkerActivity@2fe5636 2020-01-14 10:59:33.129 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityResumed() org.vulgaris.behave.ninth.WorkerActivity@2fe5636 I SHOULD SEE "WorkerActivity: onChanged(WorkInfo{mId='da800c85-485d-4cb5-9931-d3f20edf611e', mState=RUNNING, mOutputData=Data {}, mTags=[SYNC-IN-PROGRESS-TAG6c6ff5e2-b8a7-4f73-99e6-c112f7598287, org.vulgaris.behave.worker.NinthWorker], mProgress=Data {}})" HERE 2020-01-14 10:59:33.510 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityStopped() org.vulgaris.behave.seventh.DummySecondActivity@3572f3a 2020-01-14 10:59:33.512 23452-23452/org.vulgaris.behave E/APPLICATION: onActivityDestroyed() org.vulgaris.behave.seventh.DummySecondActivity@3572f3a 2020-01-14 11:00:30.624 23452-23583/org.vulgaris.behave I/WM-WorkerWrapper: Worker result SUCCESS for Work [ id=da800c85-485d-4cb5-9931-d3f20edf611e, tags={ SYNC-IN-PROGRESS-TAG6c6ff5e2-b8a7-4f73-99e6-c112f7598287, org.vulgaris.behave.worker.NinthWorker } ] 2020-01-14 11:00:30.673 23452-23452/org.vulgaris.behave E/WorkerActivity: onChanged(WorkInfo{mId='da800c85-485d-4cb5-9931-d3f20edf611e', mState=SUCCEEDED, mOutputData=Data {}, mTags=[SYNC-IN-PROGRESS-TAG6c6ff5e2-b8a7-4f73-99e6-c112f7598287, org.vulgaris.behave.worker.NinthWorker], mProgress=Data {}})这对于测试2不正确。正如我应该看到的“ ...最后自动获得的数据”。当恢复WorkerActivity时
为什么在恢复WorkerActivity后LiveData观察器不会自动触发？
我当前的Android应用程序使用archWorkerRuntimeVersion ='2.3.0-beta02'api“ androidx.work:work-runtime:$archWorkerRuntimeVersion” api“ androidx.work:work-runtime-ktx：$ ...
Lifecycle.DESTROYED状态