How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?

I think you're looking for dispatch_after(). It requires your block to accept no parameters, but you can just let the block capture those variables from your local scope instead.

int parameter1 = 12;float parameter2 = 144.1;// Delay execution of my block for 10 seconds.dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 10 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{    NSLog(@"parameter1: %d parameter2: %f", parameter1, parameter2);});

More: https://developer.apple.com/documentation/dispatch/1452876-dispatch_after

You can use dispatch_after to call a block later. In Xcode, start typing dispatch_after and hit Enter to autocomplete to the following:

Here's an example with two floats as "arguments." You don't have to rely on any type of macro, and the intent of the code is quite clear:

Swift 3, Swift 4

let time1 = 8.23let time2 = 3.42// Delay 2 secondsDispatchQueue.main.asyncAfter(deadline: .now() + 2.0) {    print("Sum of times: \(time1 + time2)")}

Swift 2

let time1 = 8.23let time2 = 3.42// Delay 2 secondsdispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(2.0 * Double(NSEC_PER_SEC))), dispatch_get_main_queue()) { () -> Void in        println("Sum of times: \(time1 + time2)")}

Objective C

CGFloat time1 = 3.49;CGFloat time2 = 8.13;// Delay 2 secondsdispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{    CGFloat newTime = time1 + time2;    NSLog(@"New time: %f", newTime);});

How about using Xcode built-in code snippet library?

Update for Swift:

Many up votes inspired me to update this answer.

The build-in Xcode code snippet library has dispatch_after for only objective-c language. People can also create their own Custom Code Snippet for Swift.

Write this in Xcode.

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(<#delayInSeconds#> * Double(NSEC_PER_SEC))), dispatch_get_main_queue(), {        <#code to be executed after a specified delay#>    })

Drag this code and drop it in the code snippet library area.

Bottom of the code snippet list, there will be a new entity named My Code Snippet. Edit this for a title. For suggestion as you type in the Xcode fill in the Completion Shortcut.

For more info see CreatingaCustomCodeSnippet.

Update Swift 3

Drag this code and drop it in the code snippet library area.

DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(<#delayInSeconds#>)) {    <#code to be executed after a specified delay#>}