问题
I'm new to swift & spritekit and wanted to know how is it possible to detect if the home button is pressed ?
The main problem is that I have NSTimer.scheduledTimerWithTimeInterval running to generate multiple characters in didMoveToView, and everything is going well, but when I pause the game with home button and restart the game a few seconds later, the characters floods out alot. I assume that the NSTimer had not been paused , therefore, flooding alot of characters when relaunching the app. I would want to know a simple solution and example, how will I pause when home button is pressed, and resuming when the app relaunches ? I would love to here from you!
testEnemy = NSTimer.scheduledTimerWithTimeInterval(1.2,
target: self,
selector: "timerUpdate",
userInfo: nil,
repeats: true)
///This is the part of the project code for generating the characters within the didMoveToView
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("appEnterIntoBackGround:"), name:UIApplicationDidEnterBackgroundNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("appBecomeActive:"), name:UIApplicationWillEnterForegroundNotification, object: nil)
//start the timer and calls the timerUpdate method every 1.0 seconds
myTimer = NSTimer.scheduledTimerWithTimeInterval(1.0,
target: self,
selector: "timerUpdate",
userInfo: nil,
repeats: true)
if(skview.level == 3) {
myTimer2 = NSTimer.scheduledTimerWithTimeInterval(1.0,
target: self,
selector: "timerUpdate",
userInfo: nil,
repeats: true)
}
testEnemy = NSTimer.scheduledTimerWithTimeInterval(1.2,
target: self,
selector: "timerUpdate",
userInfo: nil,
repeats: true)
}
func appEnterIntoBackGround(notification : NSNotification) {
let skview = self.view as! GameSKView!
print("App is in Background")
testEnemy.invalidate() //remove timer here when add enter into background.
if(skview.level == 3) {
myTimer2.invalidate()
}
myTimer.invalidate()
}
func appBecomeActive(notification : NSNotification) {
let skview = self.view as! GameSKView!
// print("App is active now")
//add your timer again when app enter into foreground
testEnemy = NSTimer.scheduledTimerWithTimeInterval(1.2,target: self,selector: "timerUpdate",userInfo: nil,repeats: true)
if(skview.level == 3) {
myTimer2 = NSTimer.scheduledTimerWithTimeInterval(1.0,
target: self,
selector: "timerUpdate",
userInfo: nil,
repeats: true)
}
testEnemy = NSTimer.scheduledTimerWithTimeInterval(1.2,
target: self,
selector: "timerUpdate",
userInfo: nil,
repeats: true)
}
回答1:
You can use NSNotificationCenter for that will fire a notification when you app enter into background or foreground as shown into below code:
var testEnemy : NSTimer?
override func didMoveToView(view: SKView) {
/* Setup your scene here */
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("appEnterIntoBackGround:"), name:UIApplicationDidEnterBackgroundNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("appBecomeActive:"), name:UIApplicationWillEnterForegroundNotification, object: nil)
testEnemy = NSTimer.scheduledTimerWithTimeInterval(1.2,
target: self,
selector: "timerUpdate",
userInfo: nil,
repeats: true)
}
And below is the helper methods:
func timerUpdate() {
print("called")
}
func appEnterIntoBackGround(notification : NSNotification) {
print("App is in Background")
testEnemy!.invalidate() //remove timer here when add enter into background.
}
func appBecomeActive(notification : NSNotification) {
print("App is active now")
//add your timer again when app enter into foreground
testEnemy = NSTimer.scheduledTimerWithTimeInterval(1.2,target: self,selector: "timerUpdate",userInfo: nil,repeats: true)
}
来源：https://stackoverflow.com/questions/33052867/how-to-pause-and-restart-nstimer-scheduledtimerwithtimeinterval-in-spritekit-sw