我正在实施 Firebase Jobdispatcher,触发时间指定在 10 到 20 秒之间。这是我安排工作的代码:
public static void scheduleCompatibleJob(Context context) {
FirebaseJobDispatcher dispatcher = new FirebaseJobDispatcher(new GooglePlayDriver(context));
Job myJob = dispatcher.newJobBuilder()
.setService(DataTrackerJobService.class) // the JobService that will be called
.setTag("api_trigger")
.setRecurring(true)
.setLifetime(Lifetime.FOREVER)
.setTrigger(Trigger.executionWindow(10, 20)) // 10 to 20 seconds
.setReplaceCurrent(true)
.setRetryStrategy(RetryStrategy.DEFAULT_LINEAR)
.setConstraints(Constraint.ON_ANY_NETWORK)
.build();
dispatcher.mustSchedule(myJob);
}
以及服务等级:
public class DataTrackerJobService extends JobService {
@Override
public boolean onStartJob(final JobParameters job) {
Log.e("start job", "started " + job);
(new Handler()).postDelayed(new Runnable() {
@Override
public void run() {
Log.e("handler", "run");
jobFinished(job, true);
}
}, 2000);
return true;
}
@Override
public boolean onStopJob(JobParameters job) {
Log.e("stop job", "stopped " + job);
return false;
}
}
作业调度程序正在运行,但 logcat 中的时间不正确。随着工作的每次重新安排,时间差距不断扩大,而且从来没有在10到20秒之间。
06-07 11:19:16.429 26174-26174/com.example.jobdispatcher E/start 作业:已启动 com.firebase.jobdispatcher.JobInspiration@f4250de4
06-07 11:19:18.432 26174-26174/com.example.jobdispatcher E/处理程序:运行
06-07 11:20:16.436 26174-26174/com.example.jobdispatcher E/start 作业:已启动 com.firebase.jobdispatcher.JobInspiration@f16ceb31
06-07 11:20:18.438 26174-26174/com.example.jobdispatcher E/处理程序:运行
06-07 11:21:58.519 26174-26174/com.example.jobdispatcher E/start 作业:已启动 com.firebase.jobdispatcher.JobInspiration@f4c635cd
06-07 11:22:00.520 26174-26174/com.example.jobdispatcher E/处理程序:运行
06-07 11:23:40.602 26174-26174/com.example.jobdispatcher E/start 作业:已启动 com.firebase.jobdispatcher.JobInspiration@f15f8e29
06-07 11:23:42.605 26174-26174/com.example.jobdispatcher E/处理程序:运行
06-07 11:25:52.642 26174-26174/com.example.jobdispatcher E/start 作业:已启动 com.firebase.jobdispatcher.JobInspiration@f48c1045
06-07 11:25:54.644 26174-26174/com.example.jobdispatcher E/处理程序:运行
06-07 11:28:52.652 26174-26174/com.example.jobdispatcher E/start 作业:已启动 com.firebase.jobdispatcher.JobInspiration@f3b49821
06-07 11:28:54.655 26174-26174/com.example.jobdispatcher E/处理程序:运行
06-07 11:32:04.688 26174-26174/com.example.jobdispatcher E/start 作业:已启动 com.firebase.jobdispatcher.JobInspiration@e7f3c1bd
06-07 11:32:06.690 26174-26174/com.example.jobdispatcher E/处理程序:运行
请检查 logcat 中的时间。指导我我在哪里出错了,或者它应该只以这种方式工作吗?基本上我想在 24 小时的时间间隔内实现它,但我想知道这是否有效,然后一次作业将在触发时间中指定的时间加倍后被调用。
如果您查看 Trigger 类的源代码,您会发现您不确定您的作业是否会在给定时间运行。
/**
* Creates a new ExecutionWindow based on the provided time interval.
*
* @param windowStart The earliest time (in seconds) the job should be
* considered eligible to run. Calculated from when the
* job was scheduled (for new jobs) or last run (for
* recurring jobs).
* @param windowEnd The latest time (in seconds) the job should be run in
* an ideal world. Calculated in the same way as
* {@code windowStart}.
* @throws IllegalArgumentException if the provided parameters are too
* restrictive.
*/
public static JobTrigger.ExecutionWindowTrigger executionWindow(int windowStart, int windowEnd) {
if (windowStart < 0) {
throw new IllegalArgumentException("Window start can't be less than 0");
} else if (windowEnd < windowStart) {
throw new IllegalArgumentException("Window end can't be less than window start");
}
return new JobTrigger.ExecutionWindowTrigger(windowStart, windowEnd);
}
还应该注意的是,只有当上一个重复工作完成后,才会开始下一个重复工作。因此,当你的工作时间长且成本高时,下一次执行时间可能会出乎意料。对于耗时的作业,您应该扩展 SimpleJobService。
为了创建重复任务,我使用 util 方法来创建适当的触发器:
public class JobDispatcherUtils {
public static JobTrigger periodicTrigger(int frequency, int tolerance) {
return Trigger.executionWindow(frequency - tolerance, frequency);
}
}
Usage:
class DataTrackerJobService extends SimpleJobService {
// ...
}
public static void scheduleCompatibleJob(Context context) {
FirebaseJobDispatcher dispatcher = new FirebaseJobDispatcher(new GooglePlayDriver(context));
Job myJob = dispatcher.newJobBuilder()
.setService(DataTrackerJobService.class) // the JobService that will be called
.setTag("api_trigger")
.setRecurring(true)
.setLifetime(Lifetime.FOREVER)
.setTrigger(JobDispatcherUtils.periodicTrigger(20, 1)) // repeated every 20 seconds with 1 second of tollerance
.setReplaceCurrent(true)
.setRetryStrategy(RetryStrategy.DEFAULT_LINEAR)
.setConstraints(Constraint.ON_ANY_NETWORK)
.build();
dispatcher.mustSchedule(myJob);
}
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