检查WorkManager Android之前是否已将WorkRequest命名为

Question

我使用PeriodicWorkRequest每15分钟为我执行一次任务.我想检查一下这个定期工作请求是否已经预定过.如果没有,请安排它.

     if (!PreviouslyScheduled) {
        PeriodicWorkRequest dataupdate = new PeriodicWorkRequest.Builder( DataUpdateWorker.class , 15 , TimeUnit.MINUTES).build();
        WorkManager.getInstance().enqueue(dataupdate);
      }

以前当我使用JobScheduler执行任务时,我曾经使用过

public static boolean isJobServiceScheduled(Context context, int JOB_ID ) {
    JobScheduler scheduler = (JobScheduler) context.getSystemService( Context.JOB_SCHEDULER_SERVICE ) ;

    boolean hasBeenScheduled = false ;

    for ( JobInfo jobInfo : scheduler.getAllPendingJobs() ) {
        if ( jobInfo.getId() == JOB_ID ) {
            hasBeenScheduled = true ;
            break ;
        }
    }

    return hasBeenScheduled ;
}

需要帮助构建用于工作请求的类似模块以帮助查找计划/活动工作请求.

Answer 1

将一些Tag设置为PeriodicWorkRequest任务:

    PeriodicWorkRequest work =
            new PeriodicWorkRequest.Builder(DataUpdateWorker.class, 15, TimeUnit.MINUTES)
                    .addTag(TAG)
                    .build();

然后在enqueue()工作之前使用TAG检查任务:

    WorkManager wm = WorkManager.getInstance();
    ListenableFuture<List<WorkStatus>> future = wm.getStatusesByTag(TAG);
    List<WorkStatus> list = future.get();
    // start only if no such tasks present
    if((list == null) || (list.size() == 0)){
        // shedule the task
        wm.enqueue(work);
    } else {
        // this periodic task has been previously scheduled
    }

但是如果你真的不需要知道它是否曾经安排过,你可以使用:

    static final String TASK_ID = "data_update"; // some unique string id for the task
    PeriodicWorkRequest work =
            new PeriodicWorkRequest.Builder(DataUpdateWorker.class,
                    15, TimeUnit.MINUTES)
                    .build();

    WorkManager.getInstance().enqueueUniquePeriodicWork(TASK_ID,
                ExistingPeriodicWorkPolicy.KEEP, work);

ExistingPeriodicWorkPolicy.KEEP表示该任务只安排一次,然后即使在设备重启后也会定期工作.如果您需要重新安排任务(例如,如果您需要更改任务的某些参数),则需要在此处使用ExistingPeriodicWorkPolicy.REPLACE