How can I delay a method call for 1 second?

Question

Is there an easy way delay a method call for 1 second?

I have a UIImageView that reacts on a touch event. When the touch is detected, some animations happen in the app. After one second, I want to call another method. In this case, I can't use the animationDidStop selector.

Answer 1

performSelector:withObject:afterDelay:

文件参考

Answer 2

You could also use a block

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 1 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
    [object method]; 
});

Most of time you will want to use dispatch_get_main_queue, although if there is no UI in the method you could use a global queue .

Edit:

Swift 3 version:

DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
    object.method()
}

Equally, DispatchQueue.global().asyncAfter(... might also be a good option.

Answer 3

Best way to do is :

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

you can also pass nil as withObject parameter.

example :

[self performSelector:@selector(subscribe) withObject:self afterDelay:3.0 ];

Answer 4

There are already a lot of answers and they are all correct. In case you want to use the dispatch_after you should be looking for the snippet which is included inside the Code Snippet Library at the right bottom (where you can select the UI elements).

So you just need to call this snippet by writing dispatch in code:

Answer 5

您可以使用执行选择器为0.1秒延迟方法调用后面的代码执行此操作。

[self performSelector:@selector(InsertView)  withObject:nil afterDelay:0.1]; 

Answer 6

You can also:

[UIView animateWithDuration:1.0
                 animations:^{ self.view.alpha = 1.1; /* Some fake chages */ }
                 completion:^(BOOL finished)
{
    NSLog(@"A second lapsed.");
}];

This case you have to fake some changes to some view to get the animation work. It is hacky indeed, but I love the block based stuff. Or wrap up @mcfedr answer below.

---

waitFor(1.0, ^
{
    NSLog(@"A second lapsed");
});

---

typedef void (^WaitCompletionBlock)();
void waitFor(NSTimeInterval duration, WaitCompletionBlock completion)
{
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, duration * NSEC_PER_SEC),
                   dispatch_get_main_queue(), ^
    { completion(); });
}

Answer 7

你可以这样做

[self performSelector:@selector(MethodToExecute) withObject:nil afterDelay:1.0 ];

Answer 8

Swift 2.x

let delayTime = dispatch_time(DISPATCH_TIME_NOW, Int64(1 * Double(NSEC_PER_SEC)))
 dispatch_after(delayTime, dispatch_get_main_queue()) {
 print("do some work")
}

Swift 3.x --&-- Swift 4

DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
    print("do some work")
}

or pass a escaping closure

func delay(seconds: Double, completion: @escaping()-> Void) {
    DispatchQueue.main.asyncAfter(deadline: .now() + seconds, execute: completion)
}

Answer 9

There is a Swift 3 solution from the checked solution :

self.perform(#selector(self.targetMethod), with: self, afterDelay: 1.0)

And there is the method

@objc fileprivate func targetMethod(){

}

Answer 10

在Swift 3中使用

perform(<Selector>, with: <object>, afterDelay: <Time in Seconds>)

Answer 11

NOTE: this will pause your whole thread, not just the one method.
Make a call to sleep/wait/halt for 1000 ms just before calling your method?

Sleep(1000); // does nothing the next 1000 mSek

Methodcall(params); // now do the real thing

Edit: The above answer applies to the general question "How can I delay a method call for 1 second?", which was the question asked at the time of the answer (infact the answer was given within 7 minutes of the original question :-)). No Info was given about the language at that time, so kindly stop bitching about the proper way of using sleep i XCode og the lack of classes...