如何使用 workmanager 检测新照片

Question

现在我正在使用 Firebase 上传照片，而且效果很好，并且能够重建这项工作以使用 workmanager，但我不知道如何将内容 URI 触发器传递给我的 workmanager 构建器。

val dispatcher = FirebaseJobDispatcher(GooglePlayDriver(applicationContext))
    val job = dispatcher.newJobBuilder()
            .setService(UploadJobService::class.java)
            .setTag(TAG)
            .setRecurring(true)
            .setTrigger(Trigger.executionWindow(0, 60))
            .setTrigger(Trigger.contentUriTrigger( Arrays.asList(
                    ObservedUri(Uri.parse(Environment.getExternalStorageDirectory().absolutePath), ObservedUri.Flags.FLAG_NOTIFY_FOR_DESCENDANTS))
            ))
            .setLifetime(Lifetime.FOREVER)
            .setReplaceCurrent(false)
            .setConstraints(
                    Constraint.ON_UNMETERED_NETWORK
            )
            .build()
    dispatcher.mustSchedule(job)

这是我用于 workmanager 的代码，它大部分时间都可以工作，但是当我拍照并删除时，这不起作用，因为间隔 15 分钟， 我如何注册新的唯一工作人员，当检测到新照片时将开始工作？

编辑：这是我使用的代码及其工作，但不确定我是否正确实现......

这是调度工作人员的方法：

public static void Checkfornewphotos(String ONE_MY_WORK) {
    OneTimeWorkRequest.Builder photoCheckBuilder =
            new OneTimeWorkRequest.Builder(MyWorker.class);
    photoCheckBuilder.setConstraints(new Constraints.Builder()
            .addContentUriTrigger(MediaStore.Images.Media.INTERNAL_CONTENT_URI, true)
            .addContentUriTrigger(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, true)
            .build());
    OneTimeWorkRequest Photocheck = photoCheckBuilder.build();
    WorkManager instance = WorkManager.getInstance();
    instance.enqueueUniqueWork(ONE_MY_WORK, ExistingWorkPolicy.REPLACE, Photocheck);
}

这是我的工人：

public class MyWorker extends Worker {

public MyWorker(
        @NonNull Context context,
        @NonNull WorkerParameters params) {
    super(context, params);
}

@Override
public Worker.Result doWork() {
    // Do your actual work
    try {
        Log.i(TAG, "mywork")
        Result.RETRY

    } catch (exception: Exception) {
        Log.i(TAG, "mywork")
        Result.SUCCESS
    }
    // Then start listening for more changes
    Checkfornewphotos(getTags().iterator().next());
}

}

Answer 1

WorkManager 不支持定期（即重复）内容 URI 触发器，但它支持将 OneTimeWorkRequest 与 addContentUriTrigger() 作为约束之一进行排队。

public static void scheduleWork(String tag) {
  OneTimeWorkRequest.Builder photoCheckBuilder =
      new OneTimeWorkRequest.Builder(MyWorker.class);
  photoCheckBuilder.setConstraints(new Constraints.Builder()
      .addContentUriTrigger(MediaStore.Images.Media.INTERNAL_CONTENT_URI, true)
      .addContentUriTrigger(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, true)
      .build());
  OneTimeWorkRequest photoCheckWork = photoCheckBuilder.build();
  WorkManager instance = WorkManager.getInstance();
  instance.enqueueUniqueWork(tag, ExistingPeriodicWorkPolicy.REPLACE, photoCheckWork);
}

因为它是OneTimeWorkRequest，它只会在第一次更改 URI 时触发 - 您需要在您的 Worker 完成后重新排队工作以捕捉下一次更改：

public class MyWorker extends Worker {

  public MyWorker(
    @NonNull Context context,
    @NonNull WorkerParameters params) {
    super(context, params);
  }

  @Override
  public Worker.Result doWork() {
    // Do your actual work

    // Then start listening for more changes
    scheduleWork(getTags().iterator().next());
  }
}