Label not changing countdown timer SpriteKit Objective C? - objective-c

Question

Edit no.2 , Ok, I think I have boiled this right down to the point now. I have used all your advice, and tested with breakpoints, so thank you.
The last bit I need to do, is run this wait action.
if (timerStarted == YES) {
[countDown runAction:[SKAction waitForDuration:1]];
if (countDownInt > 0) {
countDown.text = [NSString stringWithFormat:#"%i", countDownInt];
countDownInt = countDownInt - 1.0;
[self Timer];
}else{
countDown.text = [NSString stringWithFormat:#"Time Up!"];
}
The runAction: section doesn't seem to work. I am guessing this is because I have selected the wrong node to put in the place of the (SKLabelNode "countDown"). Which node could I use to run this code?
Thank you everyone who has helped so far

Answer 1

Here's an example of how to implement a countdown timer in SpriteKit.
First, declare a method that creates 1) a label node to display the time left and 2) the appropriate actions to update the label, wait for one second, and rinse/lather/repeat
- (void) createTimerWithDuration:(NSInteger)seconds position:(CGPoint)position andSize:(CGFloat)size {
// Allocate/initialize the label node
countDown = [SKLabelNode labelNodeWithFontNamed:#"Chalkduster"];
countDown.position = position;
countDown.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeLeft;
countDown.fontSize = size;
[self addChild: countDown];
// Initialize the countdown variable
countDownInt = seconds;
// Define the actions
SKAction *updateLabel = [SKAction runBlock:^{
countDown.text = [NSString stringWithFormat:#"Time Left: %ld", countDownInt];
--countDownInt;
}];
SKAction *wait = [SKAction waitForDuration:1.0];
// Create a combined action
SKAction *updateLabelAndWait = [SKAction sequence:#[updateLabel, wait]];
// Run action "seconds" number of times and then set the label to indicate
// the countdown has ended
[self runAction:[SKAction repeatAction:updateLabelAndWait count:seconds] completion:^{
countDown.text = #"Time's Up";
}];
}
and then call the method with the duration (in seconds) and the label's position/size.
CGPoint location = CGPointMake (CGRectGetMidX(self.view.frame),CGRectGetMidY(self.view.frame));
[self createTimerWithDuration:20 position:location andSize:24.0];

Answer 2

I would not use the update method. Use SKActions to make a timer. For an example
id wait = [SKAction waitForDuration:1];
id run = [SKAction runBlock:^{
// After a second this is called
}];
[node runAction:[SKAction sequence:#[wait, run]]];
Even though this will only run once, you can always embed this in an SKActionRepeatForever if you want to be called every second or whatever time interval.
Source:
SpriteKit - Creating a timer