How do I change the rate or period of a repeating task using ScheduledExecutorService?

Question

I have a modified version of the bluetooth chat sample app. I have set up a `ScheduledExecutorService` which sends a command over bluetooth at a predefined rate using `scheduleAtFixedRate`. I have set up a `PreferenceActivity` to allow the period to be modified by the user. But I'm unsure how to get the actual recurring tasks to happen with the updated period. Do I need to cancel and restart the `ScheduledExecutorService` somehow? Here's the relevant parts of my code. ``` private ScheduledExecutorService scheduleTaskExecutor; public long ReadInterval = 1; ... @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); scheduleTaskExecutor = Executors.newScheduledThreadPool(5); ... // This schedule a task to run every 1 second: scheduleTaskExecutor.scheduleAtFixedRate(new Runnable() { public void run() { // If you need update UI, simply do this: runOnUiThread(new Runnable() { public void run() { // update your UI component here. if (connected == true…

Accepted Answer

I improved the answer a bit (mainly because I too had to use `ScheduledExecutorService`). Please use this code instead of the previous one I posted, because the previous one was really on performance, for no good reason.

```
private ScheduledExecutorService scheduledExecutorService;
private ScheduledFuture<?> futureTask;
private Runnable myTask;

@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);

// Your executor, you should instanciate it once for all
    scheduledExecutorService = Executors.newScheduledThreadPool(5);

// Since your task won't change during runtime, you can instanciate it too once for all
    myTask = new Runnable()
    {
        @Override
        public void run()
        {
            // Your code to run periodically
        }
    };
}

/**
 * This method will reschedule "myTask" with the new param time
 */
public void changeReadInterval(long time)
{
    if(time > 0)
    {       
        if (futureTask != null)
        {
            futureTask.cancel(true);
        }

futureTask = scheduledExecutorService.scheduleAtFixedRate(myTask, 0, time, TimeUnit.SECONDS);
    }
}
```

Now, to reschedule your task during runtime, use the method `changeReadInterval(time);`

It will cancel the previous "timer" if it has been set and will reschedule a new one.

How do I change the rate or period of a repeating task using ScheduledExecutorService?

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