"UIScreen' doesn't have the member 'main' - swift3

Environment:
Xcode Version 8.1 beta (8T47)
Apple Swift version 3.0.1 (swiftlang-800.0.56 clang-800.0.42)
The Swift 3.0.1 compiler flagged 'UIScreen' as '...no member'.
...but the UIScreen file does have 'main':
#available(iOS 2.0, *)
open class UIScreen : NSObject, UITraitEnvironment {
#available(iOS 3.2, *)
open class var screens: [UIScreen] { get } // all screens currently attached to the device
open class var main: UIScreen { get } // the device's internal screen
I found numerous instances of a particular class not having a certain member.
And this was after converting the code to Swift 3.0.1 thru Xcode helper conversion function.
What gives?
Note: I was able to access UIScreen.main.scale via playground.
It appears that I'm working with a corrupt swift file.

Swift3.0.1 Since UIScreen is UIKit framework's class.So make sure you have imported.
import UIKit

Related

Add button in SwiftUI Stepper not hittable during XCTest

My stepper is defined as follows (Standalone WatchOS app)
Stepper(value: $myCount) {
Text("\(myCount)").font(.footnote).accessibilityIdentifier("count_label")
}.accessibilityIdentifier("my_stepper")
It is fully functional on the real / simulator devices. During a test case, defined below, I am unable to invoke the increment button. (I get an error and the button itself is not hittable, ever)
XCTAssertTrue(app.steppers["my_stepper"].waitForExistence(timeout: 10))
XCTAssertFalse(app.steppers["my_stepper"].buttons["Remove"].isEnabled)
XCTAssertTrue(app.steppers["my_stepper"].buttons["Add"].isEnabled)
-> (Error) app.steppers["my_stepper"].buttons["Add"].tap()
Error kAXErrorCannotComplete performing AXAction
kAXScrollToVisibleAction on element AX element pid
I tried to forceTap (using coordinates) with no luck. Any idea how to invoke the increment action?
While the increment and decrement buttons exist in the view stack, they are not hittable. Likely a bug in SwiftUI that impacts either WatchOS or all platforms. Best way I have found to temporarily get past the issue is using the following tutorial :
app.steppers["my_stepper"].coordinate(withNormalizedOffset: CGVector(dx: 0.9, dy: 0.5)).tap()
This is a workaround that will probably fail on different devices. For me, it would only work with Ultra 49mm watchOS 9.0. Accepting this until a better answer is found.

How to convert a complex UIKit View into a SwiftUI View?

there's a lot of code in here but please be patient I will try to explain my question
so i am trying to convert Apple's AvDepthCapture project which is in UIKit as a SwiftUI project, so i copied all the supporting files, i will attach the image for the same below, the shaders folder contain the metal files for applying filters
so I created a class same as the cameraviewcontroller and added all the properties as follows -
class CameraViewController: UIViewController, AVCapturePhotoCaptureDelegate, AVCaptureVideoDataOutputSampleBufferDelegate, AVCaptureDepthDataOutputDelegate, AVCaptureDataOutputSynchronizerDelegate, ObservableObject {
private var previewView: PreviewMetalView!
}
now when i run my app on my device it asks for camera permission but then shows a white screen instead of opening the camera and the PreviewMetalView file that i copied earlier directly from the original UIKit project,
the declaration is causing error
private var previewView: PreviewMetalView!
this line, it quits my app and says unexpectedly found nil when unwrapping an optional value but the code is the same as that of the UIKit project and UIKit project works perfectly fine on my device then why is it throwing this error!?, please help i can provide both the UIKit project and my SwiftUI project file if you want to see i really can't figure it out
there's a lot of code but this specific line is throwing error, I declared a type of PreviewMetalView but now PreviewMetalView has an initialiser which takes in a type NSCoder so what should I write there ??
like I would be declaring my variable as
var previewView = PreviewMetalView(coder: NSCoder)
what to put in place of NSCoder ?
when I opened the original UIKit project the previewView is defined as an IBOutlet to a Container View which is then linked to the CameraViewController but I cannot find where is it initialised please help!

SwiftUI fails to build preview with compiling error

When I go to view my SwiftUI through the canvas preview in Xcode 11.3.1 I am getting the error
Compiling failed: 'Color' is only available in iOS 13.0 or newer
But the project itself builds successfully and the simulator loads without any issues. I have tried clearing the build folder, quitting Xcode and rebuilding but still no luck.
Any help would be great. Thanks in advance.
SwiftUI minimum deployment target is 13.0, so if you have project with support of older version, then all SwiftUI code (including preview providers) you have to prepend with availability modifier, like
#available(iOS 13.0, *) // << here !!
struct Demo: View {
var body: some View {
VStack {
Text("Hello")
}
}
}
You Should use Assets or Other option like Color Literal for Color.
Don't use the system Color option since your deployment target is 11.4.
Man, I've had a similar issue. The problem was that sometimes my preview worked sometimes it didn't... I reviewed the diagnostics and realized that there are some #_dynamicReplacement attributes mentioned (which are used, I guess, for hot reloading). It wasn't working when I've had a file with #available attributes opened in the (adjacent) editor. When I closed that editor everything worked back again.
Magic ✨
Also one more hint from my friend - when you have a file from another target (not the one hosting your Canvas-related code) in (adjacent) editor it behaves the same way.

Swift3 and addTarget Selector code converter suggestion

In my old Swift iOS app project I use code like his:
button!.addTarget(self,action:"ratingButtonTapped:",for:.touchDown)
where ratingButtonTapped is a function in the same class
The code converter gives error
"No method declared with Objective-C selector 'ratingButtonTapped:'"
and then suggests this solution
button!.addTarget(self,action:Selector("ratingButtonTapped:"),for:.touchDown)
The only problem is that even after applying the fix, it continues to give warning
"No method declared with Objective-C selector 'ratingButtonTapped:'"
where is then suggest to wrap it in parentheses to hide the warning
...
This is my function declaration in the same classd:
func ratingButtonTapped(_ sender: UIButton) {
}
...
I guess the way I did this dated and wrong in Swift 3 - but what is the correct way then? The class has a function with name ratingButtonTapped
button.addTarget(self, action: #selector(YourClassController. ratingButtonTapped(_:)), for: .touchUpInside)
func ratingButtonTapped(_ sender:UIButton){
}

Crash during UICollectionViewCell reordering after Swift 3.0 migration

I do have a strange issue in using the reorder feature in my app's UICollectionView. We have a custom layout which is implemented to show a decoration view. The collection view uses a flow based layout. When I move the first cell from its position to last cell position for reordering of the cells, the app crashes before it calls the collection view delegate's collectionView(moveItemAt: to) method.
Attached the stack trace of this issue. You can see that crash is happening in the bridging between NSIndexPath and IndexPath. I am not sure why it is happening inside UIKit. Searching for this issue found that it appears to be bug inside UIKIt which got introduced in Swift 3.0. I tested my old build which was built before swift 3.0 migration and it works without any crashes.
Can someone tell me how can I fix this issue?
Related bugs links
UICollectionView broken after Swift 3 migration?
https://bugs.swift.org/browse/SR-2103
https://bugs.swift.org/browse/SR-2417
func handleLongGesture(_ gesture: UILongPressGestureRecognizer) {
switch(gesture.state) {
case UIGestureRecognizerState.began:
if let movingPageIndexPath = collectionView.indexPathForItem(at: gesture.location(in: collectionView)) {
collectionView.beginInteractiveMovementForItem(at: movingPageIndexPath)
}
case UIGestureRecognizerState.changed:
collectionView.updateInteractiveMovementTargetPosition(gesture.location(in: collectionView))
case UIGestureRecognizerState.ended:
collectionView.endInteractiveMovement()
default:
collectionView.cancelInteractiveMovement()
}
}