Delay a method call in objective-c - ios

Question

I know this can be done by using:
[self performSelector:#selector(myMethod) withObject:nil afterDelay:3.0]
However, the problem is that I want only 1 method call do be done.
With this function the calls will stack on top of each other. I want to make a call and if another call is made the first one will be dismissed. Ideas?

Answer 1

Once the method is executing then there is no way of stopping it.
But you can cancel if it is not fired. You can do something like this
//.... your code
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:#selector(myMethod) object:nil];
[self performSelector:#selector(myMethod) withObject:nil afterDelay:3.0];
//.... your code
In this way you can cancel previous perform request only if the myMethod is not being fired.

Answer 2

In the Code Snippet Library in Xcode you can find one called GCD: Dispatch After, which looks like this:
double delayInSeconds = 2.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
<#code to be executed on the main queue after delay#>
});
Pretty self-explanatory.

Answer 3

EDIT: Now that I know that you want to only use the most recent, you could instead use:
[self cancelPreviousPerformRequestsWithTarget:self selector:#selector(myMethod) object:nil];
See this link for more info.
ORIGINAL POST:
You could just have a BOOL that is set to NO when it reaches that section and is then reset to YES after the method is performed.
So, for example, it would look something like:
if (boolVal) {
boolVal = NO;
[self performSelector:#selector(myMethod) withObject:nil afterDelay:3.0];
}
then in your myMethod, have:
boolVal = YES;

Answer 4

You should perform this selector in some other thread to avoid stack as you asked.
use
[self performSelector:(SEL) onThread:(NSThread *) withObject:(id) waitUntilDone:(BOOL)];
In that selector you can add delay what ever you want. As this process will run in separate thread so will not stop others for the delay