dispatch_queue_t SerialQueue how check if is still running. ios GCD

Question

I need to do a validation and for this I need to know if the task is still running i use this code for launch the task

    ` SerialQueue = dispatch_queue_create("miColaEnSerie", NULL);
       dispatch_async(SerialQueue, ^{
    [self loadImageFriend:init finalWhitNumber:final img1WithArray:infoImages1 img2WithArray:infoImages2 img3WithArray:infoImages3];
    });`

Answer 1

If you have only one task at a time in your SerialQueue then you can add atomic property to a class like:

@property (assign) BOOL isSerialQueueRunning;

Then:

 isSerialQueueRunning = YES;
 dispatch_async(SerialQueue, ^{
    [self loadImageFriend:init finalWhitNumber:final img1WithArray:infoImages1 img2WithArray:infoImages2 img3WithArray:infoImages3];
    isSerialQueueRunning= NO;
 });

If however there are more tasks you add to SerialQueue you could change BOOL isSerialQueueRunning to NSInteger serialQueueTasks and increment/decrement it accordingly. Then verify if it's 0 which means nothing is in the queue at the moment.

Sometimes it's better to implement notifications to get information when the task is done and perform some action after that.