java - 我的 ScheduledThreadPoolExecutor 没有关闭

Question

我有一个带有 ScheduledThreadPoolExecutor 的 Android 库。它每两秒执行一次任务来检查条件，并在应用程序调用库的enable()函数时启动。当应用程序调用disable()函数时，该函数会取消ScheduledFuture任务并在执行器上调用shutdownNow()。问题是它没有停止。在应用程序的日志中，我可以看到禁用()被调用，并查看到达 Exec Shutdown 的位置，但我仍然看到 Exec Runnable 消息在后台运行。事实上，它会一直运行，直到我杀死该应用程序。有什么想法为什么任务没有停止吗？相关代码如下:

private ScheduledThreadPoolExecutor exec;
private ScheduledFuture<?> sf;


private void enable(){
            exec = new ScheduledThreadPoolExecutor(1);
            long period = 2000; 
            exec.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
            exec.setContinueExistingPeriodicTasksAfterShutdownPolicy(false);
            sf = exec.scheduleAtFixedRate(new SwitchCheck(), 0, period, TimeUnit.MILLISECONDS);
}


private void disable(){  
        if(exec != null) {
            try {
                Log.d(LOG_TAG,"Exec Shutdown");
                sf.cancel(true);
                exec.shutdownNow();
                exec = null;
            } catch (Exception e){
                e.printStackTrace();
            }
        }
}

class SwitchCheck implements Runnable {

    @Override
    public void run() {
        Log.e(LOG_TAG, "***Exec Runnable***");

    }
}

这是相关的logcat。 updateVisibility 被调用的地方就是我离开 Activity 的地方。

01-13 10:28:41.941 2584-2584/com.genericappname I/Core: onEnable in ENABLING
01-13 10:28:41.941 2584-2584/com.genericappname D/Core: SDK state change from ENABLING to ENABLED
01-13 10:28:41.941 2584-3650/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:41.941 2584-3650/com.genericappname D/Core: ThisId: 0 thisExpectedId: 23
01-13 10:28:42.241 2584-2584/com.genericappname D/Core: enable ENABLED
01-13 10:28:42.251 2584-3694/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:45.491 2584-2584/com.genericappname V/ActivityThread: updateVisibility : ActivityRecord{38270d8e token=android.os.BinderProxy@177d3607 {com.genericappname/com.genericappname.Demo}} show : true
01-13 10:28:45.501 2584-2584/com.genericappname D/SRIB_DCS: log_dcs ThreadedRenderer::initialize entered! 
01-13 10:28:45.501 2584-2669/com.genericappname D/mali_winsys: new_window_surface returns 0x3000,  [1440x2560]-format:1
01-13 10:28:45.561 2584-2584/com.genericappname D/ViewRootImpl: changeCanvasOpacity: opaque=false
01-13 10:28:45.891 2584-2584/com.genericappname D/DEMO: onPause
01-13 10:28:45.941 2584-3650/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:45.951 2584-2584/com.genericappname D/Core: disable
01-13 10:28:45.951 2584-2584/com.genericappname D/Core: SDK state change from ENABLED to DISABLING
01-13 10:28:45.951 2584-2584/com.genericappname I/Core: onDisable
01-13 10:28:45.951 2584-2584/com.genericappname D/Core: SDK state change from DISABLING to INITIALIZED
01-13 10:28:45.951 2584-2584/com.genericappname D/Core: Exec Shutdown
01-13 10:28:46.001 2584-2584/com.genericappname I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@177d3607 time:87045589
01-13 10:28:46.011 2584-2584/com.genericappname D/DEMO: onStop
01-13 10:28:46.011 2584-2584/com.genericappname D/DEMO: onDestroy
01-13 10:28:47.941 2584-3650/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:47.941 2584-3650/com.genericappname D/Core: ThisId: 0 thisExpectedId: 23
01-13 10:28:49.941 2584-3650/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:49.941 2584-3650/com.genericappname D/Core: ThisId: 0 thisExpectedId: 23
01-13 10:28:51.941 2584-3650/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:51.941 2584-3650/com.genericappname D/Core: ThisId: 0 thisExpectedId: 23
01-13 10:28:53.941 2584-3650/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:53.941 2584-3650/com.genericappname D/Core: ThisId: 0 thisExpectedId: 23
01-13 10:28:55.941 2584-3650/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:55.941 2584-3650/com.genericappname D/Core: ThisId: 0 thisExpectedId: 23
01-13 10:28:57.951 2584-3650/com.genericappname E/Core: ***Exec Runnable***
01-13 10:28:57.951 2584-3650/com.genericappname D/Core: ThisId: 0 thisExpectedId: 23

Answer 1

在调用 disable 之前第二次调用该方法时会发生什么:

private void enable(){
            exec = new ScheduledThreadPoolExecutor(1); // Creates a NEW scheduler and takes the place of the old one. But the old one still exists and does its duty!
            long period = 2000; 
            exec.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
            exec.setContinueExistingPeriodicTasksAfterShutdownPolicy(false);
            sf = exec.scheduleAtFixedRate(new SwitchCheck(), 0, period, TimeUnit.MILLISECONDS);
}

exec 将指向一个新的执行器，第一个执行器将继续执行任务。

您需要检查是否

1. 您已经有一个尚未关闭的执行程序。
2. 您已经有了任务计划。如果是这样，enable 就是一个空操作。