I want to set property value, but getting the error "Cannot assign to the result of this expression".
let operationPageViewController:UIPageViewController = UIPageViewController(transitionStyle: UIPageViewControllerTransitionStyle.Scroll, navigationOrientation: UIPageViewControllerNavigationOrientation.Horizontal, options: nil)
operationPageViewController.viewControllers = ["firstViewController","secondViewController"]
This property is inaccessible or did I do something wrong?
As Christian wrote in the comment, you are supposed to give other arguments like direction, animated, and completion. You need to also make sure that the view controllers that you send are UIViewcontrollers, not string.
func setViewControllers(viewControllers: AnyObject[]!, direction: UIPageViewControllerNavigationDirection, animated: Bool, completion: ((Bool) -> Void)!)
Related
I've tried to replicate the "Usage" section of CalendarKit's documentation and I simply can't get the EventView.data when the user selects an EventView.
My controller conforms to DayViewController and the EventViews display normally on the DayView on my screen.
override func dayViewDidSelectEventView(_ eventview: EventView) {
print("Event has been selected: \(eventview.data)")
}
This is the method being executed when the user presses the EventView and the only problem is that "eventview has no member data". I've checked the definition of the library class and it really has no data member or no methods that would extract the event or anything.
Basically the question is - How do I get the event data here?
I understand that this is simple and I thank you for sparing some time in order to help.
thank you for your question. The documentation is not up-to-date, I'll make sure to update it.
Please, use the following approach to get the EventDescriptor which would help you identify the event in your application model layer. For example, you could use userInfo dictionary to store an event identifier.
override func dayViewDidSelectEventView(_ eventView: EventView) {
guard let descriptor = eventView.descriptor as? Event else {
return
}
print("Event has been selected: \(descriptor) \(String(describing: descriptor.userInfo))")
// You can use the userInfo dictionary to identify which event has been selected
}
It is giving me the Error: Cannot call value of non-function type 'HTTPURLResponse?'
It should be caused by #escaping but I cannot make it work in the sentence below. Please help, Swift 3.0, AlamofireImage.
There are other similar answers but cannot make them work with my code below.
func getNetworkImage(_ urlString: String, completion: #escaping ((UIImage) -> Void)) -> (ImageRequest) {
let queue = decoder.queue.underlyingQueue
let request = Alamofire.request(urlString)
let imageRequest = ImageRequest(request: request)
imageRequest.request.response(
queue: queue,
responseSerializer: Request.imageResponseSerializer(),
completionHandler: { response in
guard let image = response.result.value else {
return
}
let decodeOperation = self.decodeImage(image) { image in
completion(image)
self.cacheImage(image, urlString: urlString)
}
imageRequest.decodeOperation = decodeOperation
}
)
return imageRequest
}
The error message: Cannot call value of non-function type 'HTTPURLResponse?' is telling you that the instance variable value can not be accessed. The bad thing is that it is telling you this in the wrong line of code. That may be the reason why it was so difficult to find.
The structure of the response object has changed. You code:
guard let image = response.result.value else {
return
}
Won't work anymore because the response object is of type DefaultDataResponse not HTTPResponse...
In order to access the data/image you need to go with response.response. depending on what you want to access:
response.response?.value(forKey: "")
Check the other method calls and properties. I believe you will find the data you are looking for.
In my Objective C code I had this:
if ([view conformsToProtocol:#protocol(UITextInputTraits)]) {
id<UITextInputTraits> field = view;
field.enablesReturnKeyAutomatically = YES;
}
Now I'm trying to convert that to swift, so I did this:
if var field = view as? UITextInputTraits {
field.enabledReturnKeyAutomatically = true
}
I'm getting a compiler error saying that 'field' is immutable. What's the right way to accomplish this?
The problem is caused by Swift's peculiar way of dealing with optional protocol requirements. Optional protocol properties have no setter. (I regard this as a bug in the language.) You'll have to work around it.
You can say (horrible):
switch view {
case let field as UITextField:
field.enablesReturnKeyAutomatically = true
case let field as UITextView:
field.enablesReturnKeyAutomatically = true
default: break
}
Another way (equally horrible):
let setter = #selector(setter:UITextInputTraits.enablesReturnKeyAutomatically)
if view.responds(to:setter) {
view.perform(setter, with: 1 as NSNumber)
}
I'm reading many articles about how you shouldn't check an object for nil. It's a objC paradigm and it's a bad design and w/ swift it's been eliminated. So my question is, per example below, can you pass thru "group" as nil value? does the nil-checking mechanism happen when the function is called, hence removing the need to implement if(group==nil){..} ?
func deleteMembershipForGroup(group:GroupData){
}
You need to use an optional:
func deleteMembershipForGroup(group:GroupData?){
if let groupReal = group {
// not nil
}
}
Yes! Thomas Kilian is right and it works for me! You will then be able to pass a nil parameter. You will also notice that using optional variable, it will also removed the warning saying the variable "group" will always be true.
func deleteMembershipForGroup(group:GroupData?){
if let groupReal = group { <--- Warning gone!
// not nil
}
}
I'm trying to switch out a direct integer with a variable in swift, but for some reason I'm getting this error and I have no idea. The end goal is to get my currentValue (line 76) to replace the 100's on line 41 - could anyone let me know how I could accomplish this without the error? New to swift and having a hard time (background in objective-c, figured something this simple would not stop me in my tracks!)
Full .swift file here: http://pastebin.com/K6UHkNEv
EDIT:
// these values change the number of squares
let _gameView = CGOLView(gridWidth:100, gridHeight:100)
#IBOutlet weak var tileSizeSlider: UISlider!
#IBAction func sliderValueChanged(sender: UISlider) {
var currentValue = Int(sender.value)
print("\(currentValue)")
}
should work as:
// these values change the number of squares
let _gameView = CGOLView(gridWidth:currentValue, gridHeight:currentValue)
#IBOutlet weak var tileSizeSlider: UISlider!
#IBAction func sliderValueChanged(sender: UISlider) {
var currentValue = Int(sender.value)
print("\(currentValue)")
}
instead I get this error:
Use of unresolved identifier 'currentValue'
and if I try to create custom int's and input them:
var gridWidthValue = 50
var gridHeightValue = 50
like this:
let _gameView = CGOLView(gridWidth:gridWidthValue, gridHeight:gridHeightValue)
I get:
'ViewController.Type' does not have a member named 'gridHeightValue'
Any help would be appreciated - thanks stackoverflow community!
David.
currentValue is a local variable to sliderValueChanged.
Instead you should instantiate _gameView in init. Note however, you still won't be able to use currentValue.
If this is a one off sort of thing, you can always make _gameView an optional and then create it when you have adjusted the slider. This is admittedly a little clumsy.
I am not familiar with Conway's Game of Life, but looking at the code, it seems CGOLView's init does some adjustment based on the grid width and height. The reason I am mentioning this is that you could always change the view's frame size, however, you'd then also need to make some other mods to the tileViews for it to look proper.
As to why gridWidthValue/gridHeightValue is not working. Those are properties defined in an instance. Hence you would need to do somethign like self.gridWithValue to reference it. However, you cannot do that when defining the property such as
let _gameView = CGOLView(gridWidth:gridWidthValue, gridHeight:gridHeightValue)
This is also why instantiating _gameView in init is the way to go.
Your problem is that you cannot access the variable currentValue because it is inside of a function. You have to declare that value outside of the function to be able to use it outside of the function.