I'm working on a portion of my application where I animate messages based on a users progress through time. So, essentially timed out messages.
I have a counter and two labels:
var timer = NSTimer()
var timerCount = 0
@IBOutlet weak var bannerLabel: UILabel!
@IBOutlet weak var messageLabel: UILabel!
I have an NSTimer that's calling a count method (countingUp) where my timerCount
variable is incremented. Of course the method fires every second as one would expect. The countingUp
method calls a method called updateLabels
(each second).
func countingUp() {
// other irrelevant stuff
updateLabels()
timerCount++
}
func updateLabels() {
if timerCount == 1 {
animateMessage(messageLabel, delay: 7.0)
animateBanner(bannerLabel, delay: 7.0)
bannerLabel.text = "Message 1"
messageLabel.text = "Blah Blah"
}
// quite a few more of these conditions, though
// I use a switch in my app.
}
And here are my animation methods:
func animateBanner(banner: UILabel, delay: Double){
UIView.animateWithDuration(1.2, animations: {
banner.alpha = 1.0
})
if delay > 0.0 {
UIView.animateWithDuration(3, delay: delay, options: [], animations: {
banner.alpha = 0.1
}, completion: nil)
}
}
func animateMessage(label: UILabel, delay: Double){
label.alpha = 0.0
UIView.animateWithDuration(1.2, animations: {
label.center.y -= 20
label.alpha = 1.0
})
UIView.animateWithDuration(1.2, delay: delay, options: [], animations: {
label.alpha = 0.1
}, completion: nil)
}
To prove that my method is being called and that my label is indeed at alpha of 0
I've taken a screen shot:
My animations fade out perfectly, but they never fade in, they just appear. What is the reason for this?
The animation happens in a completion block, so basically you are running two animations at the same time, I indicate what is happening in the code in the code below.
func animateMessage(label: UILabel, delay: Double){
label.alpha = 0.0
//1 - Start animation 1
UIView.animateWithDuration(1.2, animations: {
//3 - Finish animation 1
label.center.y -= 20
label.alpha = 1.0
})
//2 - Start animation 2
UIView.animateWithDuration(1.2, delay: delay, options: [], animations: {
//4 - Finish animation 2
label.alpha = 0.1
}, completion: nil)
}
What you can do is to call one animation on the completion of the other animation:
func animateMessage(label: UILabel, delay: Double){
label.alpha = 0.0
UIView.animateWithDuration(1.2, delay: delay, options: [], animations: {
label.center.y -= 20
label.alpha = 1.0
}, completion:{finished in
if (finished) {
UIView.animateWithDuration(1.2, delay: delay, options: [], animations: {
label.alpha = 0.1
}, completion: nil)
}
})