我正在撰写有关JobScheduler的教程,并发现了一种奇怪的行为。 我要求在1秒钟内安排3个不同的作业(.setOverrideDeadline(1000)),但它们都被提交并运行了两次...以下是代码:
public class MyApplication extends Application {
private static final int JOB_ID_HanlderThread = 100;
private static final int JOB_ID_ExecutorService = 200;
private static final int JOB_ID_AsyncTask = 300;
JobScheduler mJobScheduler;
ExecutorService myExecutorServiceForJobs=null;
private static MyApplication INSTANCE;
public static MyApplication getInstance(){
return INSTANCE;
}
/**
* Called when the application is starting, before any activity, service,
* or receiver objects (excluding content providers) have been created.
* Implementations should be as quick as possible (for example using
* lazy initialization of state) since the time spent in this function
* directly impacts the performance of starting the first activity,
* service, or receiver in a process.
* If you override this method, be sure to call super.onCreate().
*/
@Override
public void onCreate() {
Log.e("MyApplication", "*********************** onCreate *****************************");
super.onCreate();
//use only for the ExceutorService case
INSTANCE=this;
//instanciate your JobScheduler
mJobScheduler= (JobScheduler) getSystemService(JOB_SCHEDULER_SERVICE);
Log.e("MyApplication", "onCreate: JobScheduler instanciate");
//this first example use the HandlerThread (no need of executor service)
//---------------------------------------------------------------------
//define your JobServices here
JobInfo.Builder builder = new JobInfo.Builder(JOB_ID_HanlderThread,
new ComponentName( getPackageName(),
MyJobServiceUsingHandlerThread.class.getName() ) );
//begin in one second
builder.setOverrideDeadline(1000);
int returnedValue;
//the return value is failure(0) or success(1) not the JobId if success (Javadoc wrong)
returnedValue=mJobScheduler.schedule( builder.build() );
//launch it
if( returnedValue <= 0 ) {
//If something goes wrong (manage exception/error is better than logging them)
Log.e("MyApplication", "onCreate: JobScheduler launch the task failure");
}else{
//nothing goes wrong
Log.e("MyApplication", "onCreate: JobScheduler launch the task suceess JOB_ID_HanlderThread "+returnedValue);
}
//this second example use ExecutorService
//---------------------------------------
//then again define your Job and launch it
JobInfo.Builder builder1 = new JobInfo.Builder(JOB_ID_ExecutorService,
new ComponentName( getPackageName(),
MyJobServiceUsingExecutor.class.getName() ) );
//begin in one second
builder1.setOverrideDeadline(1000);
//launch it
returnedValue=mJobScheduler.schedule( builder1.build() );
if( returnedValue <= 0 ) {
//If something goes wrong (manage exception/error is better than logging them)
Log.e("MyApplication", "onCreate: JobScheduler launch the task failure");
}else{
//nothing goes wrong
Log.e("MyApplication", "onCreate: JobScheduler launch the task suceess JOB_ID_ExecutorService "+returnedValue);
}
//this third example use AsyncTask
//--------------------------------
//then again define your Job and launch it
JobInfo.Builder builder2 = new JobInfo.Builder(JOB_ID_AsyncTask,
new ComponentName( getPackageName(),
MyJobServiceUsingAsyncTask.class.getName() ) );
//begin in one second
builder2.setOverrideDeadline(1000);
//launch it
returnedValue=mJobScheduler.schedule( builder2.build() );
if( returnedValue <= 0 ) {
//If something goes wrong (manage exception/error is better than logging them)
Log.e("MyApplication", "onCreate: JobScheduler launch the task failure");
}else{
//nothing goes wrong
Log.e("MyApplication", "onCreate: JobScheduler launch the task suceess JOB_ID_AsyncTask "+returnedValue);
}
}
使用这段代码,我希望我的任务只运行一次,但是如果我查看日志,我得到了:10-20 06:45:13.118 13041-13041/? E/MyApplication: *********************** onCreate *****************************
10-20 06:45:13.122 13041-13041/? E/MyApplication: onCreate: JobScheduler instanciate
10-20 06:45:13.126 13041-13041/? E/MyApplication: onCreate: JobScheduler launch the task suceess JOB_ID_HanlderThread 1
10-20 06:45:13.127 13041-13041/? E/MyApplication: onCreate: JobScheduler launch the task suceess JOB_ID_ExecutorService 1
10-20 06:45:13.130 13041-13041/? E/MyApplication: onCreate: JobScheduler launch the task suceess JOB_ID_AsyncTask 1
10-20 06:45:13.559 13041-13041/? E/MyJobServiceHandler: onStartJob called <--------------------------------
10-20 06:45:13.572 13041-13041/? E/MyJobServiceExecutor: onStartJob called <--------------------------------
10-20 06:45:14.133 13041-13041/? E/MyJobServiceAsync: onStartJob called <--------------------------------
10-20 06:45:14.141 13041-13041/? E/MyJobServiceAsync: onStartJob called <--------------------------------
10-20 06:45:18.571 13041-13066/? E/MyHandler: The work is done in a separate thread called MyJobServiceUsingHandlerThread
10-20 06:45:18.573 13041-13041/? E/MyJobServiceHandler: onDestroy called, Looper is dead <******************************************
10-20 06:45:18.574 13041-13041/? E/MyJobServiceHandler: onStartJob called <--------------------------------
10-20 06:45:18.576 13041-13067/? E/MyRunnable: The work is done in a separate thread called MyJobServiceUsingExecutorService
10-20 06:45:18.577 13041-13041/? E/MyJobServiceExecutor: onDestroy called, executor service is dead <******************************************
10-20 06:45:18.577 13041-13041/? E/MyApplication: killMyExecutorServiceForJob called
10-20 06:45:18.577 13041-13041/? E/MyApplication: myExecutorServiceForJobs isShutDown
10-20 06:45:18.580 13041-13041/? E/MyJobServiceExecutor: onStartJob called <--------------------------------
10-20 06:45:19.145 13041-13070/? E/MyAsyncTask: The work is done in a separate thread called AsyncTask #1
10-20 06:45:19.145 13041-13041/? E/MyAsyncTask: The work is finished <******************************************
10-20 06:45:23.576 13041-13075/? E/MyHandler: The work is done in a separate thread called MyJobServiceUsingHandlerThread
10-20 06:45:23.577 13041-13041/? E/MyJobServiceHandler: onDestroy called, Looper is dead <******************************************
10-20 06:45:23.582 13041-13076/? E/MyRunnable: The work is done in a separate thread called MyJobServiceUsingExecutorService
10-20 06:45:23.584 13041-13041/? E/MyJobServiceExecutor: onDestroy called, executor service is dead <******************************************
10-20 06:45:23.584 13041-13041/? E/MyApplication: killMyExecutorServiceForJob called
10-20 06:45:23.584 13041-13041/? E/MyApplication: myExecutorServiceForJobs isShutDown
10-20 06:45:24.147 13041-13077/? E/MyAsyncTask: The work is done in a separate thread called AsyncTask #2
10-20 06:45:24.148 13041-13041/? E/MyAsyncTask: The work is finished <******************************************
在本教程中,我分别使用HandlerThread、ExecutorService和AsyncTask来运行三个任务,以解释如何在后台线程中执行工作。我展示了这些不同的技术,因为有些情况下您可能希望将作业排队到同一线程(HandlerThread)中,或者管理线程池(ExecutorService),或者只是使用未受管理的线程(AsyncTask)。
我在MyApplication:onCreate方法中定义了这些作业并安排它们的调度。
要深入了解代码,请访问GitHub:https://github.com/MathiasSeguy-Android2EE/JobSchedulerForGitHub。
setPeriodic
有同样的问题。有解决的办法吗? - ShahrozKhan91