I wonder how to animate a node to which I assign a few seconds until next action takes place.
For example, if a button is pressed, a node begins to move for three seconds, and after the three seconds pass away, a picture or text appears on the screen.
Should I use NSTimer and NSTimerInterval?
Try to use this fairly simple approach that will help you to manage animation. This animation will take 3 seconds and at the end it will execute a completion handler.
UIView.animateWithDuration(3.0, animations: { () -> Void in
//animate object here
}) { (state: Bool) -> Void in
// hide animated object here
}
Related
The following code from here shows how to do a fade-out for NSView in Swift:
NSAnimationContext.runAnimationGroup({ context in
context.duration = 1
self.view.animator().alphaValue = 0
}, completionHandler: {
self.view.isHidden = true
self.view.alphaValue = 1
})
I am using this code to display a status notification -> i.e. the text appears, stays for around a few seconds, and then fades out. Is there a way to delay the start of the fade out to accomplish this?
Is there a way to delay the start of the fade out to accomplish this?
One way is to use NSTimer to run your animation after whatever delay you choose. For example, you could pass a block containing your code to +scheduledTimerWithTimeInterval:repeats:block:, and once the interval expires the block will run.
I want to know if it is possible to suspend and then resume a work item on the main queue whilst maintaining the '.asyncAfter' time. If not, is there a workaround to achieve this?
At a certain point, I queue up the following DispatchWorkItem:
dispatchWorkItem = DispatchWorkItem(qos: .userInteractive, block: {
self.view.backgroundColor = UIColor.workoutBackgroundColor
self.runTimer()
self.timerButton.animateableTrackLayer.removeAnimation(forKey: "strokeEndAnimation")
self.isRestState = false
})
I queue this up using:
DispatchQueue.main.asyncAfter(deadline: delayTime, execute: self.dispatchWorkItem))
(delayTime being a parameter to the function)
Now, the problem I am running into is how can I suspend this work item if the user performs a 'pause' action in my app.
I have tried using the DispatchQueue.main.suspend() method but the work item continues to execute after the specified delay time. From what I have read, this method should suspend the queue and this queued work item since it is not being executed. (Please correct me if I am wrong there!)
What I need to achieve is the work item is 'paused' until the user performs the 'resume' action in the app which will resume the work item from where the delay time left off.
This works on background queues that I have created when I do not need to make UI updates; however, on the main queue is appears to falter.
One workaround I have considered is when the user performs the pause action, storing the time left until the work item was going to be executed and re-adding the work item to the queue with that time on the resume action. This seems like a poor quality approach and I feel there is a more appropriate method to this.
On that, is it possible to create a background queue that on execution, executes a work item on the main queue?
Thanks in advance!
On that, is it possible to create a background queue that on execution, executes a work item on the main queue?
You are suggesting something like this:
var q = DispatchQueue(label: "myqueue")
func configAndStart(seconds:TimeInterval, handler:#escaping ()->Void) {
self.q.asyncAfter(deadline: .now() + seconds, execute: {
DispatchQueue.main.async(execute: handler())
})
}
func pause() {
self.q.suspend()
}
func resume() {
self.q.resume()
}
But my actual tests seem to show that that won't work as you desire; the countdown doesn't resume from where it was suspended.
One workaround I have considered is when the user performs the pause action, storing the time left until the work item was going to be executed and re-adding the work item to the queue with that time on the resume action. This seems like a poor quality approach and I feel there is a more appropriate method to this.
It isn't poor quality. There is no built-in mechanism for pausing a dispatch timer countdown, or for introspecting the timer, so if you want to do the whole thing on the main queue your only recourse is just what you said: maintain your own timer and the necessary state variables. Here is a rather silly mockup I hobbled together:
class PausableTimer {
var t : DispatchSourceTimer!
var d : Date!
var orig : TimeInterval = 0
var diff : TimeInterval = 0
var f : (()->Void)!
func configAndStart(seconds:TimeInterval, handler:#escaping ()->Void) {
orig = seconds
f = handler
t = DispatchSource.makeTimerSource()
t.schedule(deadline: DispatchTime.now()+orig, repeating: .never)
t.setEventHandler(handler: f)
d = Date()
t.resume()
}
func pause() {
t.cancel()
diff = Date().timeIntervalSince(d)
}
func resume() {
orig = orig-diff
t = DispatchSource.makeTimerSource()
t.schedule(deadline: DispatchTime.now()+orig, repeating: .never)
t.setEventHandler(handler: f)
t.resume()
}
}
That worked in my crude testing, and seems to be interruptible (pausable) as desired, but don't quote me; I didn't spend much time on it. The details are left as an exercise for the reader!
I want to synchronize setFocusModeLockedWithLensPosition, setWhiteBalanceModeLockedWithDeviceWhiteBalanceGains and setExposureModeCustomWithDuration calls.
Is there a logic order to call thoses functions ?
What i want to do is to start Running session when i am sure that focus, balance and exposure are properly set (i want to set values, not in automatic)
I have tried to lock the configuration, then call the 3 functions, then unlock, then startRunning on session. I put nil in the 3 completion handler parameters.
What i see in this case is that my image preview is not pretty (kind of blue filter). I have to wait before having a good image quality. What i want is to display the image only when it is good. I want do be notified.
So i tried to cascade my 3 calls with completion handler. in some cases, the completion handler is not called. I suppose this is when i want to put my lens position to 0.4 and the current lens position is 0.4.
So i don't know which is the best method.
Thanks
You can set your camera options in completion handler like this. It will wait till focus has been set to set exposure and the same principle will work with white balance and exposure. You can read more about camera setting here.
var AVCGains:AVCaptureWhiteBalanceGains = AVCaptureWhiteBalanceGains()
AVCGains.redGain = 1.0;
AVCGains.greenGain = 1.0;
AVCGains.blueGain = 1.0;
self.camera?.focusMode = .locked
self.camera?.exposureMode = .locked
self.camera?.whiteBalanceMode = .locked
self.camera?.setFocusModeLockedWithLensPosition(focus_point, completionHandler: {(timestamp:CMTime) -> Void in
print("Focus applied")
self.camera?.setExposureModeCustomWithDuration(CMTimeMake(1,10), iso: 100, completionHandler: {(timestamp:CMTime) -> Void in
print("Exposure applied")
self.camera?.setWhiteBalanceModeLockedWithDeviceWhiteBalanceGains(AVCGains, completionHandler: {(timestamp:CMTime) -> Void in
print("White Balance applied")
// All settings have been applied, start running session
})
})
})
So I would like to make a block of code that will run inside the sprite node every frame. The result would be me tapping and creating a bubble there that would then float up using sine. Is that possible to code into the bubble? Sorry if this seems vague, I'm just not sure what to call it. The closest thing I can think of it cloning and each clone runs the same script every frame. Anyways, Here's what I have now.
let bubble = SKSpriteNode(imageNamed:"bubble")
bubble.position.x = CGFloat(rand())*self.frame.width
bubble.position.y = -20
//Code for bubble to run each frame
self.addChild(bubble)
I think that what you are looking for is enumerateChildNodesWithName. When it is called, it will run the code it contains on every node with the name you put in it.
bubble.name = "bubble"
If you name bubble "bubble", all of its child nodes will also be named "bubble".
enumerateChildNodesWithName("bubble"){node, stop in
let bubbleChild:SKSpriteNode = node as! SKSpriteNode
//Run the code telling them what to do here. You should make it so that
//it can figure out how to move the node a slight amount based on its position
}
You could call this by putting it in a function that is called by a timer, and the timer should be called frequently, like every 0.017 seconds (Approximately 60 times a second) so that the motion is smooth. For example:
var timer = NSTimer.scheduledTimerWithTimeInterval(NSTimeInterval(0.017), target: self, selector: Selector("moveBubbles:"), userInfo: nil, repeats: true)
Then, to make a function that the timer calls:
func moveBubbles(timer: NSTimer!){
//enumerateChildNodesWithName here
}
There is more information on enumerateChildNodesWithName here, and more information on NSTimer here.
Are there any known cases where running an SKAction using runAction does not complete?
I launch several 'runAction' on different SKNode. In order to synchronize all these actions, I use a counter that is incremented inside the completion block of each SKAction. When the counter reach the exact number of launched SKAction then the animations is completed.
From time to time one SKAction does not complete then the animation never complete.
// Several actions are launched...
myNode.runAction(myActions,completion:{
checkCompletion()
})
// Check if all actions completed
//
// numberOfLaunchedActions: number of actions launched
// logDebug: some log helper
func checkCompletion() {
// This counter is initialized earlier
numberOfCompletedActions++
logDebug(">> Actions completed: \(numberOfCompletedActions)/\(numberOfLaunchedActions)")
if numberOfCompletedActions == numberOfLaunchedActions {
/// some statements
logDebug("Animation Completed!")
}
}
Actions are dynamically generated and are composed of sequence of following actions:
waitForDuration
scaleTo
moveBy
hide
unhide
No removeFromParent nor runAction nor runBlock.
The action I focus my attention on is the following:
let waitAction = SKAction.waitForDuration(0.4)
let scaleAction = SKAction.scaleTo(0.1, duration: 2.0)
scaleAction.timingMode = .EaseOut
let myAction = SKAction.sequence([
waitAction,
scaleAction,
])
There is one known case: adding action after Remove from parent in a sequence: SKAction runAction does not execute completion block
As explained in comment:
Remove from parent is causing the rest of the actions in the
sequence not to be called, since the involved node is no longer in
the scene. The sequence didn't complete, therefore the completion
block shouldn't be called.