afterDelay efficiency and cancelPreviousPerformRequestsWithTarget - ios

Question

Two fold question:
Am I using the afterDelay in a correct/efficient manor? I'm new to objective-c so just wanted to be sure I'm using it properly.
Whenever I call the this again before the time is up, it starts running two methods (which makes sense). After some research I found cancelPreviousPerformRequestWithTarget but it seems to cancel out the ability to call the method again. I wasn't sure if there was a better way to handle this.
[self beginShow:5 myIncrease:0.1];
- (void)beginShow:(CGFloat)duration myIncrease:(CGFloat)myIncrease{
CGFloat currentTime = 0.0;
while(duration > currentTime){
[self performSelector:#selector(setRed) withObject:nil afterDelay:currentTime];
[self performSelector:#selector(setTorchToLevelOn) withObject:nil afterDelay:currentTime];
currentTime = currentTime+myIncrease;
[self performSelector:#selector(setBlack) withObject:nil afterDelay:currentTime];
[self performSelector:#selector(setTorchToLevelOff) withObject:nil afterDelay:currentTime];
currentTime = currentTime+myIncrease;
[self performSelector:#selector(setPurple) withObject:nil afterDelay:currentTime];
[self performSelector:#selector(setTorchToLevelOn) withObject:nil afterDelay:currentTime];
currentTime = currentTime+myIncrease;
[self performSelector:#selector(setDefault) withObject:nil afterDelay:currentTime];
[self performSelector:#selector(setTorchToLevelOff) withObject:nil afterDelay:currentTime];
currentTime = currentTime+myIncrease;
}
}

Answer 1

try this code, i think you need this
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:#selector(method name) object:nil];

Answer 2

The answer to first question is NO. This logic could be performed using NSTimer and macro NS_ENUM to declare enumeration type YourState that has several states(for example YourStateDefault = 0, YourStateRed, YourStateBlack, YourStatePurple).
Why so? Because it gives you control on the logic flow and easy-to-maintain/debug solution. You could check what the state of the system just by referring to the currentState property(read below).
than
(void)beginShow:(CGFloat)duration myIncrease:(CGFloat)myIncrease {
check if a timer running, than deactivate it.
set currentState to the initial state value.
setup new timer with repeatInterval = myIncrease, set value of remainTime == duration, action:#selector(toggleState)
run timer.
}
(void) toggleState {
it should change current state saved in currentState property to the next one and call update UI logic. The toggle action should be performed only for positive remainTime value.
If remainTime became negative you should deactivate timer and return, if it positive run logic.
Determinate which state should go next using switch statement based on currentState value. Set current state to new one and run [self changeUIAccordingToState: currentState].
You also need decrease "remainTime" on every toggle action.
}
(void)changeUIAccordingToState:(YourState)state {
it should change color and torchToLevel accordingly
}