'Use of Unresolved Identifier' in Swift - ios

So I have been making an app, and everything has been working great. But today I made a new class like usual and for some reason in this class I can't access Public/Global variable from other classes. All the other classes can, but now when ever I try to make a new class I can't. How would this be fixed?
I am using Swift and Xcode 6.
Working Class:
import UIKit
import Foundation
import Parse
import CoreData
var signedIn = true
class ViewController: UIViewController {
New Class:
import UIKit
class NewClass: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
signedIn = false
}
But on signedIn = false
I get the error:
use of unresolved identifier "signedIn"

One possible issue is that your new class has a different Target or different Targets from the other one.
For example, it might have a testing target while the other one doesn't. For this specific case, you have to include all of your classes in the testing target or none of them.

Once I had this problem after renaming a file. I renamed the file from within Xcode, but afterwards Xcode couldn't find the function in the file. Even a clean rebuild didn't fix the problem, but closing and then re-opening the project got the build to work.

'Use of Unresolved Identifier' in Swift my also happen when you forgot to import a library. For example I have the error:
In which I forgot the UIKit
import UIKit

Sometimes the compiler gets confused about the syntax in your class. This happens a lot if you paste in source from somewhere else.
Try reducing the "unresolved" source file down to the bare minimum, cleaning and building. Once it builds successfully add all the complexity back to your class.
This has made it go away for me when re-starting Xcode did not work.

Another place I've seen this error is when your project has multiple targets AND multiple bridging headers. If it's a shared class, make sure you add the resource to all bridging headers.
A good tip to is to look in the left Issue Navigator panel; the root object will show the target that is issuing the complaint.

For me this error happened because I was trying to call a nested function. Only thing I had to do to have it fixed was to bring the function out to a scope where it was visible.

In my case, I had an Object-C file which was also in the same Target Membership. I fixed by adding #import "YourObjectCFileHeader.h" inside file Bridging-Header.h

Because you haven't declared it. If you want to use a variable of another class you must use
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
var DestViewController : ViewController = segue.destinationViewController as ViewController
DestViewController.signedIn = false
}
You have to put this code at the end of the NewClass code

Your NewClass inherits from UIViewController. You declared signedIn in ViewController. If you want NewClass to be able to identify that variable it will have to be declared in a class that your NewClass inherits from.

I got this error for Mantle Framework in my Objective-Swift Project.
What i tried is ,
Check if import is there in Bridging-Header.h file
Change the Target Membership for Framework in Mantle.h file as shown in below screenshot.
Toggle between Private Membership first build the project , end up with errors.
Then build the project with Public Membership for all the frameworks appeared for Mantle.h file, you must get success.
It is just a bug of building with multiple framework in Objective-C Swift project.

If this is regarding a class you created, be sure that the class is not nested.
F.e
A.swift
class A {
class ARelated {
}
}
calling var b = ARelated() will give 'Use of unresolved identifier: ARelated'.
You can either:
1) separate the classes if wanted on the same file:
A.swift
class A {
}
class ARelated {
}
2) Maintain your same structure and use the enclosing class to get to the subclass:
var b = A.ARelated

I did a stupid mistake. I forgot to mention the class as public or open while updating code in cocoapod workspace.
Please do check whether accesor if working in separate workspace.

You forgot to declare the variable. Just put var in front of signedIn = false

My issue was calling my program with the same name as one of its cocoapods. It caused a conflict. Solution: Create a program different name.

This is not directly to your code sample, but in general about the error. I'm writing it here, because Google directs this error to this question, so it may be useful for the other devs.
Another use case when you can receive such error is when you're adding a selector to method in another class, eg:
private class MockTextFieldTarget {
private(set) var didCallDoneAction = false
#objc func doneActionHandler() {
didCallDoneAction = true
}
}
And then in another class:
final class UITextFieldTests: XCTestCase {
func testDummyCode() {
let mockTarget = MockTextFieldTarget()
UIBarButtonItem(barButtonSystemItem: .cancel, target: mockTarget, action: MockTextFieldTarget.doneActionHandler)
// ... do something ...
}
}
If in the last line you'd simply call #selector(cancelActionHandler) instead of #selector(MockTextFieldTarget.cancelActionHandler), you'd get
use of unresolved identifier
error.

Related

Swift: import framework but can't find class in it

I import a swift framework to a swift project, but when I call the class in this framework, Xcode throw a compile error "Use of undeclared type 'xxxx(class name)' ".
I feel Xcode have found the framework, otherwise it will complaint "can't find xxx(framework name)".
But why Xcode can't find the class of this framework.
I have tried remove and re-add framework, and delete DeivedData files, but all of them not work. I haven't use CocoaPods to import framework.
Any idea?
In a Framework that was built for Release (and not Debug), the class symbols need to be accessible.
Make sure you are you trying to access Public or Open classes from your Swift framework.
// set the Framework class to Public
public class rnHello{
// set the initializer to public, otherwise you cannot invoke class
public init() {
}
// set the function to public, as it defaults to internal
public static func world() {
print("hello from a static method")
}
}
Now you can access this via your Swift code or if you attach lldb using:
lldb) po rnHello.world()
Make sure that the FrameWorkSearch path in the BuildSettings of the project is reflecting the correct path to your framework.

Swift Protocol in Framework

so i have this weird problem that's been bugging me for the last few hours.
I have a framework in which I created a protocol named ChatDelegate (code bellow)
public protocol ChatDelegate: class {
func chat(_ chatCollectionView: UICollectionView, didSelect message: Message)
}
and a ViewController (not in the framework), which conforms to the ChatDelegate, like so
extension ChatContainerViewController: ChatDelegate {
func chat(_ chatCollectionView: UICollectionView, didSelect message: Message) {
print("did select")
}
}
but the compiler still complains that the ChatContainerViewController does not conform to the protocol and I don't understand why?? The function has the exact same header (I also tried putting public in front ...didn't help).
Any help would be much appreciated.
UPDATE
I figured it out. The problem was that I had Message class in my project and in the framework and the compiler didn't know which one to choose. Adding ModuleName in front (ModuleName.Message) fixed it. :D
I had the same issue. The file that defined the protocol had a target membership in both the framework and the application targets. I solved the issue by making the file that defined the protocol only have a target membership in the framework and then adding an import <FrameworkName> to the code in the application target that needed to use the protocol.

Compile and runtime failures when importing interfaces with category extensions in XCode 7

I'm trying to get an example of running OpenEars with the RapidEars plugin running in Swift 2.2 (XCode 7.3.1). However, I suspect I'm having a larger issue with using Objective-C interfaces with extensions in a Swift project (or my understanding of how that works).
The OpenEars code is Obj-C. However I was able to get it running in my swift project through the standard Obj-C -> Swift translation techniques.
Abbreviated code follows. The full example is on a forked Github and updated to Swift-2.2: https://github.com/SuperTango/OpenEars-with-Swift-
This following example is working great. You can see the entire project by checkng out the "working-opears-swift2.2" tag.
OpenEarsTest-Bridging-Header.h:
#import <OpenEars/OELanguageModelGenerator.h>
#import <OpenEars/OEAcousticModel.h>
#import <OpenEars/OEPocketsphinxController.h>
#import <OpenEars/OEAcousticModel.h>
#import <OpenEars/OEEventsObserver.h>
ViewController.swift:
class ViewController: UIViewController, OEEventsObserverDelegate {
var openEarsEventsObserver = OEEventsObserver()
override func viewDidLoad() {
super.viewDidLoad()
loadOpenEars()
}
func loadOpenEars() {
self.openEarsEventsObserver = OEEventsObserver()
self.openEarsEventsObserver.delegate = self
var lmGenerator: OELanguageModelGenerator = OELanguageModelGenerator()
addWords()
var name = "LanguageModelFileStarSaver"
lmGenerator.generateLanguageModelFromArray(words, withFilesNamed: name, forAcousticModelAtPath: OEAcousticModel.pathToModel("AcousticModelEnglish"))
lmPath = lmGenerator.pathToSuccessfullyGeneratedLanguageModelWithRequestedName(name)
dicPath = lmGenerator.pathToSuccessfullyGeneratedDictionaryWithRequestedName(name)
}
func startListening() {
do {
try OEPocketsphinxController.sharedInstance().setActive(true)
OEPocketsphinxController.sharedInstance().startListeningWithLanguageModelAtPath(lmPath, dictionaryAtPath: dicPath, acousticModelAtPath: OEAcousticModel.pathToModel("AcousticModelEnglish"), languageModelIsJSGF: false)
} catch {
NSLog("Error!")
}
}
// A whole bunch more OEEventsObserverDelegate methods that are all working fine...
func pocketsphinxDidStartListening() {
print("Pocketsphinx is now listening.")
statusTextView.text = "Pocketsphinx is now listening."
}
Up until this point, everything is working great.
However, In order to use the "RapidEars" plugin, the documentation (http://www.politepix.com/rapidears/) says to:
Add the framework to the project and ensure it's being included properly.
import two new files (that are both "categories" to existing OpenEars classes):
#import <RapidEarsDemo/OEEventsObserver+RapidEars.h>
#import <RapidEarsDemo/OEPocketsphinxController+RapidEars.h>
Change methods that used: startListeningWithLanguageModelAtPath to use startRealtimeListeningWithLanguageModelAtPath
add two new OEEventsObservableDelegate methods.
func rapidEarsDidReceiveLiveSpeechHypothesis(hypothesis: String!, recognitionScore: String!)
func rapidEarsDidReceiveFinishedSpeechHypothesis(hypothesis: String!, recognitionScore: String!)
The new code can be found by checking out the rapidears-notworking-stackoverflow tag from the above github repo
Problem 1:
When doing completion in the XCode editor, the editor sees WILL perform autocompletion on the startRealtimeListeningWithLanguageModelAtPath method, however when the code is run, it always fails with the error:
[OEPocketsphinxController startRealtimeListeningWithLanguageModelAtPath:dictionaryAtPath:acousticModelAtPath:]: unrecognized selector sent to instance 0x7fa27a7310e0
Problem 2:
When doing auto completion in the XCode editor, it doesn't see the two new delegate methods defined in RapidEarsDemo/OEPocketsphinxController+RapidEars.h.
I have a feeling that these are related, and also related to the fact that they failing methods are defined as Categories to Objective-C classes. But that's only a guess at this point.
I've made sure that the RapidEars framework is imported and in the framework search path.
Can anyone tell me why this is happening? Or if there's some Swift magic incantation that I missed?
The problem could be the one described in the link below, where category methods in a static library produce selector not recognized runtime errors.
Technical Q&A QA1490: Building Objective-C static libraries with categories

Create my own cocoapods library in swift error: Use of unresolved identifier 'ABXXXView'

I am following http://guides.cocoapods.org/making/using-pod-lib-create guide to created my own swift library.
Briefly steps:
pod lib create MyLibrary
And the question with Yes,Swift etc. (Example project created)
Created my own class ABXXXView to replace the default in 'Pods/Development Pods/MyLibrary/pod/Classes/ReplaceMe.swift'
Then i want to make an example in Example for MyLibrary in ViewController.swift, when i used the class ABXXXView under my own pods, i got the error as title described:
import MyLibrary
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let vi = ABXXXView()
self.view.addSubview(vi)
}
}
Which means can't find "ABXXXView", but i have import MyLibrary, any hint? Thanks!
EDIT:
If i recreated a project with Objc language, everything works fine.
Add the scope of your class "ABXXXView" to public.
public class ABXXXView : UIView {
}
I hope it will solve your problem.

I want to call a class function written in Swift from the AppDelegate (which is in Objective C). What am I doing wrong?

I have a swift file "SomeController.swift" it is like this:
import Foundation
func performSomeStuff() {
println("Performing stuff")
}
Now in the app delegate, I am trying to do this: (note that the swift bridging header is imported)
[SomeController performSomeStuff]
But its not working.
I have also tried this:
import Foundation
class SomeController:NSObject {
class func performSomeStuff() {
println("Performing stuff")
}
}
But it still fails.
What is the correct way?
Add:
#objc
before the class keyword in your swift code so it will be:
#objc class SomeStuff: NSObject {
}
Also add #obj in front of any function that you want to call.
Then in your app delegate make sure to use #import "projectName-Swift.h"
Are you able to access "SomeController" class in objective-c, if not then you firstly need to add "${ProjectName}-Swift.h file and add Swift compilation support in Build settings as:
And for accessing methods from Swift to Objective-C, add
import Foundation
class SomeStuff:NSObject {
#objc class func performSomeStuff() {
println("Performing stuff")
}
}
before functions name.
In some cases, you need finer grained control over how your Swift API is exposed to Objective-C. You can use the #objc attribute if your Swift class doesn’t inherit from an Objective-C class, or if you want to change the name of a symbol in your interface as it’s exposed to Objective-C code.
https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/BuildingCocoaApps/InteractingWithObjective-CAPIs.html
Ok, So I figured it out. First, here's the correct way. Its like some of you said:
In the swift file, I have it like this:
class MyController:NSObject{
class func performTask {
// Here my task is running.
}
}
Then in the app delegate, I just import the swift header file. And do this:
[MyController performTask];
Now for the part I had wrong. It was an error on my part, but maybe it'll be useful to someone else out there.
When I first created the first swift file, I had placed it inside a folder within the my Source folder. But when I started having multiple swift files, I moved the bridging header outside that folder and into the main Source folder (just for organising).
The problem was, it did not give me a direct error to tell me what was the problem. I had to check the issue navigator to identify the problem.
Hope this helps someone out there.

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