Implementing next threading solutions in Swift / Objective-C

Question

I started to learn programming for iOS and I want to find out how to implement next Java functions with threads in Swi

Answer 1

For 2, I would use serial queue:

dispatch_queue_t myQueue;

And implement my queue as of below:

myQueue = dispatch_queue_create("my_serial_queue", DISPATCH_QUEUE_SERIAL);

dispatch_async(myQueue, ^{
    for (int i = 0; i < 10000; i++) {
        usleep(100);
    }
    NSLog(@"Task 1 done");
});

dispatch_async(myQueue, ^{
    NSLog(@"Task 2 done");
});

Answer 2

my answer for the first (1) solution (wait until all threads finish its execution):

dispatch_group_t group = dispatch_group_create();
dispatch_group_async(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
    // block1
    NSLog(@"Task Block1");
    [NSThread sleepForTimeInterval:6.0];
    NSLog(@"Task Block1 End");
});


dispatch_group_async(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
    // block2
    NSLog(@"Task Block2");
    [NSThread sleepForTimeInterval:5.0];
    NSLog(@"Task Block2 End");
});


dispatch_group_wait(group, DISPATCH_TIME_FOREVER); // blocks current thread

for second solution (2)

I didn't find for GCD method like isRunning, so I just use Boolean variable

before starting async task set variable isRunning to true ... ... when async task is finished we can use next callback:

dispatch_group_notify(_signInitThread, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^ {
    isRunning = false;
});