How to make thread sleep for seconds in iOS?

Question

In iOS env, is it possible to make current thread sleep for seconds, then execute my code? NSTimer, GDC or any technique is okay for me.

Answer 1

Use the class method + (void)sleepForTimeInterval:(NSTimeInterval)ti

The variable NSTimeInterval is of type double and represents the number of seconds to sleep

// Block for .5 seconds
[NSThread sleepForTimeInterval:.5];

Answer 2

it cannot be easier.

sleep(seconds);

Answer 3

Either

[self performSelector:@selector(YourFunctionName) withObject:(can be Self or Object from other Classes) afterDelay:(Time Of Delay)];`

or

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 1 * NSEC_PER_SEC), 
    dispatch_get_main_queue(), ^{
    //your method 
});

Answer 4

It would be better if you shared what you have done but it here you go.

There are a few options you can go with:

Option 1

// Standard Unix calls
sleep(); 
usleep();

Some documentation regarding the sleep function can be found here. You'll find that they are actually C functions but since Objective-C is a strict superset of C we can still use the sleep and usleep functions.

Option 2

[NSThread sleepForTimeInterval:2.000];//2 seconds

The Apple documentation for this method states:

Sleeps the thread for a given time interval.

Discussion

No run loop processing occurs while the thread is blocked.

Option 3

 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 
                              1 * NSEC_PER_SEC),
                dispatch_get_main_queue(),
                ^{ 
                     // Do whatever you want here. 
                 });

The Grand Central Dispatch route is a pretty good way of doing things as well. Here is the Apple Documentation for Grand Central Dispatch which is quite a good read.

There is also this question that might be pretty useful How to Wait in Objective-C

Answer 5

it depends how you are creating (spawning) your threads. For example if you are creating your thread with NSThread class, you can use the two class methods :

sleepUntilDate:
sleepForTimeInterval:

But generally it's a bad idea to handle the threading management yourself, because multithreading programming is very hard. You can use GCD or operations queues for example to handle the multithreading in your application.