Use of unresolved identifier - app development with Swift Project 2 - ios

Sorry - I realise this is a complete beginner question, but I've googled for half a day now and still can't resolve the issue myself.
I'm using xCode 8.3 and trying to complete the apple - app development with swift course - end of unit project 2. I'm told (by the Apple book) I should be able to run the app without build failures, even if it isn't finished.
I get an unresolved identifier error when I add the following code to my ViewControler file, inside the class ViewController: UIViewController.
func updateUI() {
correctWordLabel.text = game.formattedWord
scoreLabel.text = "Wins: \(totalWins), Losses: \(totalLosses)"
treeImageView.image = UIImage(named: "Tree \(currentGame.incorrectMovesRemaining)")
}
xCode suggests I change it to Game.formattedWord, but when i do get 'Instance member 'formattedWord' cannot be used on type 'Game' ViewController.Swift'.
Could someone please help?
I've checked the sample code from Apple about 100 times and they are def saying it should be game.formattedWord in the code.
Thank you!

Try correctWordLabel.text = currentGame.formattedWord
I think it’s a typo.
Earlier in your code you create an instance of the Game struct called currentGame so you are accessing the formattedWord variable inside that instance. That’s why you couldn’t change it to Game. Game is like the blueprint of the struct. currentGame is your actual ‘thing’ Hope that makes some sense.

Related

Swift migration: 'Notification' is ambiguous for type lookup in this context' in some places

I'm making a migration from Swift 2.3 to Swift 5 with a lot of pain and well, I'm ending the migration but I'm still getting an error in some places of the code:
Notification' is ambiguous for type lookup in this context
I recieved before this error but now I'm getting this in places like
var notifications = [Notification]
self.notifications = (sql.execute() as NSArray) as! [Notification]
and
func isAlreadyExists(notification: Notification) -> Bool {
I thought to change Notification name but the app is not mine and is big... very big and is not possible to do this and well, I don't know what to do.
Thanks in advance.
Edit:
Tried to do the same as suggested in How can I disambiguate a type and a module with the same name? but doing "import (class|struct|func|protocol|enum) Module.Symbol" desn't works (I see where Notification is in the project but doesn't work ProjectName.class).
Finally, it worked by changing the class name and adding it to a file called <Project_name>-Bridging-Header.
Doing this I could call the class with var example = <Project_name>.<className>

Today-Widget "Unable to load" error

From time to time widget crashing with "unable to load" error.
Is anyone know how to fix it?
Widget haven't requests to server or smth else.
Unable to load in today extension mostly appears when:
You extension crash due to some reason
It takes more memory than what is provided by the system. (Memory Limit : max 16MB approx.)
Debug your app extension to find out the exact problem.
Refer to Xcode's Debug Gauge for Memory and CPU utilization.
Edit:
Debugging today extension
You can debug your extension the same way you debug your main project. Just select that particular target scheme in your Xcode and run the project.
Now try using the breakpoints and other print statements in the extension’s code and you are good to go. Happy coding..😊
REBOOT the device.
This saved me.
I have faced this error
I used a custom view. But forgot to check Is initial viewController.
Set an entry point form "show attribute inspector" as an initial view controller
I have faced the same issue where it wasn't showing anything. Even my debug option was not working. I found an article online which helped me a lot. I would like to recommend this here.
Most of the time it is the size of the content view that crashes the widget. in that case, use this code snippet in TodayViewController.
Code snippet
override func viewWillAppear(_ animated: Bool)
{
var currentSize: CGSize = self.preferredContentSize
currentSize.height = 200.0
self.preferredContentSize = currentSize
}
Link for further research.
Make sure you have more than 0 rows
I have built a today-widget similar to Building a Simple Widget for the Today View.
I had none of the above issues. Mine was 0 row (I had no data for this particular day and hence, 0 row). I did not expect that it could be the problem since in the main-app, you can have empty table-view.
If you see unable to load message, make sure you have at least 1 row.
Set this in viewDidLoad:
extensionContext?.widgetLargestAvailableDisplayMode = .expanded
In my case NotificationCenter.framework was accidentally deleted from Link Binary With Libraries in Build Phases tab in widget target.

ibeacon app development using swift

everyone, I am a new one to iOS app development using swift.
I am studying a ibeacon app sample code which downloaded from the https://github.com/SelimSalihovic/CityOS-iBeacon-Swift-Tutorial.
while I was running the code, there are errors in the code as shown the following page, could you help me how to solve it, please! Thanks in advance!
The first one is easily solveable by unwrapping the value (the exclamation mark)
NSUUID(UUIDString: "B9407F30-F5F8-466E-AFF9-25556B57FE6D")!
Second and third error are due to the beacons array not declaring the content's type (AnyObject means it can't be any class, which is not guaranteed to have the properties the code is looking for) so just go to line 16 and make the following change
var beacons : [CLBeacon] = []
However this will still not compile because the LocationServices framework hasn't been imported in the project, to do so just add
import CoreLocation
There will be some more errors now, specifically at line 26 and 55 in BeaconTableViewController
Fix-It has the right suggestion for these, basically you need to cast note.object by adding as! [CLBeacon] and remove the unwrapping on switch proximity because the value isn't optional
The code now compiles properly for me, I'm not sure it will work because I can't test right now, but it should be a step in the right direction
Good luck with your journey in iBeacons, they're a pretty fun technology to work with

App stuck in splash screen on iOS 9 with no error

My app gets stuck on splash screen in iOS 9 both on iPhone and simulator. I can run it on iOS 8 or lower on device and simulator with no problem. My colleague working on the same app has exactly the same problem.
There is no error or anything, just hangs on splash screen. If I stop it on xcode and try to run it from the phone or simulator directly, it would run without any problem.
By the way, I don't see didFinishLaunchingWithOptions or willFinishLaunchingWithOptions getting called!
In your "answer" you include the code:
+(void)initialize
{
titles = #[NSLocalizedString(#"CODE", nil), NSLocalizedString(#"ERROR", nil), NSLocalizedString(#"TROUBLESHOOTING", nil)];
}
This is indeed the source of your issue. It's wise to be very careful when implementing +load or +initialize. #bbum has a great article on exactly that topic.
+initialize is invoked the first time the class (or category) is touched - when the class is initialized +initialize is called by the class loading mechanism. There is no guarantee of when in the class loading process this may happen, which is part of your problem.
In your case you are using NSLocalizedString - which under the hood can be fairly heavy. It has dependancies on several other classes (NSString, etc) and can potentially access the file system. As #bbum points out in his article, that can lead to serious trouble. In your case, this may be a nasty deadlock.
Move your titles = #[NSLocalizedString... line to a more appropriate place in your object, like an initializer, awakeAfterUsingCoder:, etc. and your immediate problem should be solved. After doing so you should check your entire codebase for instances where +initialize and +load are implemented and audit them to make sure those uses are in line with #bbum 's recommendations.
OK I found the problem. It sounds ridiculous though!!
I am using UITabBarController and inside the first controller I have a UITableViewController with a customised datasource class which would initiate a hard code table header and these headers are localised!!
+ (void)initialize {
titles = #[NSLocalizedString(#"CODE", nil), NSLocalizedString(#"ERROR", nil), NSLocalizedString(#"TROUBLESHOOTING", nil)];
}
After I traced the stacks, I realised the process gets stuck right there with no trace and error! I still don't know why!
So I came up with a workaround:
+ (void)initialize {
titles = #[#"Code",#"Error",#"Troubleshooting"];
}
And only retrieve the localised value when returning the text:
- (NSString *)titleAt:(NSInteger)index {
return NSLocalizedString(titles[index],nil);
}
I have both debug and release set to NO
You sure "any SDK" also has arm64?
Ok, I think I found the answer.
You have to specify arm64 in all "Valid Architectures".
If you don't specify arm64 or forget one the app won't start and stays on the splashscreen.
Just verified this.
Is this an Xcode 7 bug?

unable to execute command: Segmentation fault: 11 swift frontend command failed due to signal (use -v to see invocation)

I have an iOS swift program that compiles and runs fine on Xcode Beta2. When I downloaded beta4, I got a few syntax errors for the new swift language which I corrected. I now get this error:
<unknown>:0: error: unable to execute command: Segmentation fault: 11
<unknown>:0: error: swift frontend command failed due to signal (use -v to see invocation)
The problem is that it does not tell me where this error is so that I can further troubleshoot it. Where can I type -v in order to "see the invocation" and troubleshoot further? Without this, there is absolute no way to figure out the problem. Thanks in advance.
Here's how I was able to find out what the problem was:
Click on the issue in the issue navigator (⌘ + 4, then click on the line with the red ! at the start)
At the bottom of the file that appears, there should be a line that says something like:
1. While emitting IR SIL function #_TToZFC4Down8Resource12getInstancesfMS0_U__FTSS6paramsGVSs10DictionarySSPSs9AnyObject__9onSuccessGSqFGSaQ__T__7onErrorGSqFT5errorCSo7NSError8responseGSqCSo17NSHTTPURLResponse__T___T_ for 'getInstances' at /path/to/file.swift:112:5
The location where your error occurred is at the end of that line. (In this case, on line 112 of file.swift in getInstances).
I was trying to add the PayPal framework to my iOS Project (Xcode 7.2 and Objective C language). When building it did not throw any error, but when I tried to archive the Project and make the IPA, I was getting that error
unable to execute command: Segmentation fault: 11
Screenshot:
After struggling for a long time, I disabled the Bitcode in Project's Target > Build Settings > Enable Bitcode. Now the project can be archived. Please check the following screenshot.
Can't really give a straight solution on this (although I'm sure it's an Apple bug), but I just came across the exact same error message and happen to solve it. Here's what I did:
In General
Comment out recently changed Swift code (check commits) until the app compiles again
Command-click each called method in the failing line and check if there could be an ambiguity
My Example
In my case (I was using the XMPPFramework written in Objective-C) the failing code looked like this:
for roomMessage: XMPPRoomMessage in self.messages {
let slices = split(roomMessage.nickname(), { $0 == "_" }, allowEmptySlices: false)
}
Once I replaced roomMessage.nickname() with "0_test" the code didn't fail any more. So I command-clicked the method nickname() (twice) and here's what I saw:
My guess was that the Swift 1.1 compiler has problems with figuring out which method to call if the exact type of an object is not clear. So I made the type of roomMessage explicit and got another error which I fixed by removing the braces behind the nickname() method call. This made my app build again. Here's the working code:
for roomMessage: XMPPRoomMessageCoreDataStorageObject in self.messages {
let slices = split(roomMessage.nickname, { $0 == "_" }, allowEmptySlices: false)
}
I hope this helps someone out there to investigate the issue more quickly than I did.
I also had the same problem,
when I cleaned the derived data
Remove all removed derived data from Trash as well.
Stop Xcode, restart it and clean build
It should be fixed now.
In my case this error because I use Class name for variable
var MYClass : MYClass {
get {
return.....
}
}
And this fixes my problem
var myClass : MYClass {
get {
return.....
}
}
My problem was that I tried to mimic static variables with the so-called module approach (the Module design pattern). So, I had something like that (just a simple static reference to an operation queue declared at the level of a swift file):
let globalQueue: NSOperationQueue = {
let queue = NSOperationQueue()
queue.suspended = false
queue.maxConcurrentOperationCount = NSOperationQueueDefaultMaxConcurrentOperationCount
return queue
}()
So, that worked fine in Xcode 6.x.x, but ceased to compile in Xcode 7beta. Just want you guys to be aware of it.
P.S. In general, I managed to find out what was wrong from the logs (see the screenshot attached). Hope this saves you some time.
I got Segmentation fault when I called a protocol function the same protocols extension.
I had a code something in the line with this:
protocol Rotatable {
func rotate() -> Self
}
extension Rotatable {
func rotate(steps: Int) {
for _ 0..<steps { self.rotate() }
}
}
When I later made an object and declared that it would follow the Rotatable protocol I got Segmentation fault 11 and the program crashed.
Ex: this would cause Segmentation fault and crash Xcode
struct SomeStruct : Rotatable {
}
If I however first implemented the function rotate() in SomeStruct and then afterwards declared that it conformed to Rotatable there where no problem.
I had a similar today and tried the steps described here including removing files I had recently modified. Nothing seemed to work. I tried something that had been suggested when SourceKit would crash in Xcode.
I when into the derived data directory and deleted everything. The location is listed under "Preferences -> Locations -> Derived Data" There is an arrow icon right next to the path which opens finder with that directory selected. Select all the directories inside and delete them. Close Xcode and Reopen it. That made the problem disappear for me.
I think that some intermediate file is getting corrupted and the compiler does not know how to handle it.
I get this error because a silly mistake!!
in a class I defined
var url: String!?
:)
So it seems that this description is a multiple & generic error for a lot of reasons!!
This can happen as well if you are porting Objective-C code to Swift and you move an objective C protocol to swift. If you leave off the #objc at the protocol definition and you still have Objective-C code that uses that protocol you can get this error.
The solution in that case is adding #objc to the protocol
protocol MyPortedProtocol {}
changes to
#obcj protocol MyPortedProtocol {}
Also make sure any classes that implement this protocol add #objc to the methods
I did answer in "Swift compiler segmentation fault when building"
I had this error too, and i fixed like this:
check your project and find out which files are using twice and remove one, or delete all and re-add them.
Errors in my xCode
:0: error: filename "AttributedString.swift" used twice: '/Users/.../CNJOB/CNJOB/AttributedString.swift' and '/Users/.../CNJOB/CNJOB/AttributedString.swift'
:0: note: filenames are used to distinguish private declarations with the same name
:0: error: filename "APIClient.swift" used twice: '/Users/.../CNJOB/CNJOB/APIClient.swift' and '/Users/.../CNJOB/CNJOB/APIClient.swift'
:0: note: filenames are used to distinguish private declarations with the same name
Command /Applications/Xcode 3.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc failed with exit code 1
For me it's caused by adding the swift files to different targets (today extension in my case).
I forgot to add one #end after #implementation in a .m file that had multiple classes in it. Something like:
#implementation Adjust
#end
#implementation Data //#end For this class was missing
#implementation Create
#end
I got this bug because of line
self.textView.inputAccessoryView = self.toolbarItems;
If you delete it the error will gone.
My steps:
1)
Deleted Derived data
Cleared build folder Didn't help
Copied class files to another folder as backup and commented everything in this class. Error gone.
Commented code blocks one by one until
build was success.
For me the problem was mixing Generics, Extensions, and #objc.
It turns out Xcode doesn't like having #objc inside extensions of generic classes:
class FaultyClass<T: TypeValidator>: UIControl where T.ItemType == String {
}
extension FaultyClass: UITextFieldDelegate {
func textFieldDidEndEditing(_ textField: UITextField) {
}
}
The above code gives the error #objc is not supported within extensions of generic classes. So I moved the method to the class itself but didn't delete the empty extension. This got rid of the error but when I compiled the project I got the segmentation fault.
The solution was to move UITextFieldDelegate to the class declaration.
class GoodClass: <T: TypeValidator>: UIControl, UITextFieldDelegate where T.ItemType == String {
// MARK: - TextFieldDelegate
func textFieldDidEndEditing(_ textField: UITextField) {
}
}
My problem was in methods signatures:
func setCategory(categoryId: Int?, subcategoryId: Int?) -> FilterSettings {
func changeCategory(categoryId: Int?, subcategoryId: Int?, handler: #escaping (Int) -> ()) {
I don't get why compiler cannot handle such declarations.
In my case it was because of an inappropriate inout in the function parameters. So I suggest you to look for that as well.
For me it was something similar to what #LuisCien described in this answer https://stackoverflow.com/a/42803582/4075379
I didn't have any generics or #objc tags, but it was these lines of code that were causing the segmentation fault:
public extension CGFloat {
/// Whether this number is between `other - tolerance` and `other + tolerance`
func isEqual(to other: CGFloat, tolerance: CGFloat) -> Bool {
return (other - tolerance...other + tolerance).contains(self)
}
}
i.e. an extension on a primarily Objective-C primary type?
Very luckily, I was able to delete those lines because the project wasn't using anymore. That fixed the issue.
Dumb mistake. I referred to self in a Class method:
public class func FunctionName() -> UIImage {
let bundle = Bundle.init(for: type(of: self))
...
}
I run into this problem when building some legacy code whaich was not adapted for latest Swift versions.
Segmentation fault: 11
When you open Report navigator it contains some context like:
1. Apple Swift version 5.3.2 (swiftlang-1200.0.45 clang-1200.0.32.28)
2. While evaluating request IRGenSourceFileRequest(IR Generation for file "/Users/alex/Downloads/NSURLProtocolExample-Swift_complete/NSURLProtocolExample/AppDelegate.swift")
3. While emitting IR SIL function "#$s20NSURLProtocolExample11AppDelegateC11applicationAD29didFinishLaunchingWithOptionsSbSo13UIApplicationC_So12NSDictionaryCSgtF".
for 'application(application:didFinishLaunchingWithOptions:)' (at /Users/alex/Downloads/NSURLProtocolExample-Swift_complete/NSURLProtocolExample/AppDelegate.swift:17:3)
0 swift 0x000000010b2d3615 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 37
1 swift 0x000000010b2d2615 llvm::sys::RunSignalHandlers() + 85
2 swift 0x000000010b2d3bcf SignalHandler(int) + 111
3 libsystem_platform.dylib 0x00007fff2039bd7d _sigtramp + 29
...
To solve this issue:
comment the pointed line (line 17 in AppDelegate.swift)
Build and fix all others issues
uncomment line from step 1
Swift 5 Very Easy And Smooth Solution
1- Just check your last added Extension / Code / Folder File before then this issue occur
2- Just Commit the code or save that code
3- Clean and Build & DONE :-)
Happy Coding
I ran into a similar problem when switching from beta2 to beta4.
Clean
then
Build

Resources