SpriteKit - Creating a timer
Solution 1:
In Sprite Kit do not use NSTimer
, performSelector:afterDelay:
or Grand Central Dispatch (GCD, ie any dispatch_...
method) because these timing methods ignore a node's, scene's or the view's paused
state. Moreover you do not know at which point in the game loop they are executed which can cause a variety of issues depending on what your code actually does.
The only two sanctioned ways to perform something time-based in Sprite Kit is to either use the SKScene update:
method and using the passed-in currentTime parameter to keep track of time.
Or more commonly you would just use an action sequence that starts with a wait action:
id wait = [SKAction waitForDuration:2.5];
id run = [SKAction runBlock:^{
// your code here ...
}];
[node runAction:[SKAction sequence:@[wait, run]]];
And to run the code repeatedly:
[node runAction:[SKAction repeatActionForever:[SKAction sequence:@[wait, run]]]];
Alternatively you can also use performSelector:onTarget:
instead of runBlock:
or perhaps use a customActionWithDuration:actionBlock:
if you need to mimick the SKScene update:
method and don't know how to forward it to the node or where forwarding would be inconvenient.
See SKAction reference for details.
UPDATE: Code examples using Swift
Swift 5
run(SKAction.repeatForever(SKAction.sequence([
SKAction.run( /*code block or a func name to call*/ ),
SKAction.wait(forDuration: 2.5)
])))
Swift 3
let wait = SKAction.wait(forDuration:2.5)
let action = SKAction.run {
// your code here ...
}
run(SKAction.sequence([wait,action]))
Swift 2
let wait = SKAction.waitForDuration(2.5)
let run = SKAction.runBlock {
// your code here ...
}
runAction(SKAction.sequence([wait, run]))
And to run the code repeatedly:
runAction(SKAction.repeatActionForever(SKAction.sequence([wait, run])))
Solution 2:
In Swift usable:
var timescore = Int()
var actionwait = SKAction.waitForDuration(0.5)
var timesecond = Int()
var actionrun = SKAction.runBlock({
timescore++
timesecond++
if timesecond == 60 {timesecond = 0}
scoreLabel.text = "Score Time: \(timescore/60):\(timesecond)"
})
scoreLabel.runAction(SKAction.repeatActionForever(SKAction.sequence([actionwait,actionrun])))
Solution 3:
I've taken the swift example above and added in leading zeros for the clock.
func updateClock() {
var leadingZero = ""
var leadingZeroMin = ""
var timeMin = Int()
var actionwait = SKAction.waitForDuration(1.0)
var timesecond = Int()
var actionrun = SKAction.runBlock({
timeMin++
timesecond++
if timesecond == 60 {timesecond = 0}
if timeMin / 60 <= 9 { leadingZeroMin = "0" } else { leadingZeroMin = "" }
if timesecond <= 9 { leadingZero = "0" } else { leadingZero = "" }
self.flyTimeText.text = "Flight Time [ \(leadingZeroMin)\(timeMin/60) : \(leadingZero)\(timesecond) ]"
})
self.flyTimeText.runAction(SKAction.repeatActionForever(SKAction.sequence([actionwait,actionrun])))
}