I am simply trying to convert this Objective-C block to swift but there seems to be a problem, I am unable to solve. None of the variables are optional.
Objective-C - Works
[CLPlacemark hnk_placemarkFromGooglePlace:place
apiKey:YOUR_API_KEY
completion:^(CLPlacemark *placemark, NSString *addressString, NSError *error) {
}];
Swift - Gives error
CLPlacemark.hnk_placemarkFromGooglePlace(placeAtIndexPath(indexPath),"YOUR_API_KEY",
completion:{ (placemark:CLPlacemark!, addressString: NSString!, error: NSError!) -> Void in
})
Error Message:
Cannot invoke 'hnk_placemarkFromGooglePlace' with an argument list of type '(HNKGooglePlacesAutocompletePlace!, String, completion: (CLPlacemark!, NSString!, NSError!) -> Void)'
Swift Method Signature
CLPlacemark.hnk_placemarkFromGooglePlace(place:
HNKGooglePlacesAutocompletePlace!, apiKey:String!, completion:
((CLPlacemark!, String!, NSError!) -> Void)
Swift bridges NSString to String in blocks. You still use NSString in your callback, but should use String.
If you're using Swift 1.2 (or maybe even 1.1) String and NSString are compatible, but the compiler requires that you cast them. Think something like: NSString(string: mySwiftString) or String(myNSString). The error shows that you're using both a String and NSString, make sure you're using the right one in the right places.
Related
I Convert my Objective C + Swift 2.x code to Swift 3 in Xcode 8. After converting the code i am getting these new warning that i don't know if it's safe ti ignore/how to resolve it.
My Swift 3 code :
func getUserNotificationFromServer(_ completionQueue:DispatchQueue = DispatchQueue.main,callback: #escaping (_ succeeded: Bool, _ response: AnyObject?) -> Void) {
Objective C code that calls this function
[wsManager getUserFavouritesFromServer:dispatch_get_main_queue() callback:^(BOOL succeeded, id _Nullable response) {
Warning that i am receiving
Incompatible pointer types sending 'dispatch_queue_t _Nonnull' (aka
'NSObject *') to parameter of type
'OS_dispatch_queue * _Nonnull'
Any thoughts ?
I don't understand why, but the DispatchQueue is exposed as OS_dispatch_queue * in the generated {ProjectModuleName}-Swift.h .
(Better send a bug report to Apple.)
As far as I tested, just casting as suggested in the message suppresses the warning, and the code works as expected:
[wsManager getUserNotificationFromServer:(OS_dispatch_queue * _Nonnull)dispatch_get_main_queue()
callback:^(BOOL succeeded, id _Nullable response) {
I converted my project to swift 3 and am having issue with the kinvey conversion. I had this before but it now gives me this error: "Cannot convert value of type '(AnyObject!, NSError!) -> Void' to expected argument type 'KCSCustomEndpointBlock!'". How could I fix this issue?
KCSCustomEndpoints.callEndpoint("endpointName", params: params, completionBlock: {
(results: AnyObject!, error: NSError!) -> Void in
if results != nil {
}
})
Mitch94,
This has been escalated to the engineering team for adding Swift 3 example of invoking custom endpoint to the Kinvey documentation.
I will get back to you once I have more information on it.
Thanks,
Pranav
Kinvey Support
I am a bit confused on how to use completion handlers in Swift 3. Previously, in Swift 2.2, I had code like this:
transferUtility.uploadFile(tmpFileURL, bucket: bucket, key: key, contentType: contentType, expression: nil, completionHander: { (task, error) in
self.uploadCompletionHandler(task, transferError: error)
})
How can I port this to Swift 3?
I get an error that says Cannot convert value of type '(AWSS3TransferUtilityUploadTask, NSError) -> ()' to expected argument type 'AWSS3TransferUtilityUploadCompletionHandlerBlock?'
Does anyone know what could be wrong?
Check the signature of the AWSS3TransferUtilityUploadCompletionHandlerBlock, now Swift 3 doesn't allow auto type-casting. Swift 3 doesn't allow you to define the completionBlock with different signature, check the ? and ! as well.
I have working project in Xcode 7.3 with swift 2.2 version. Now I have updated Xcode 8 and migrated to swift 3. Now my project contains errors specially for blocks like success block of afnetworking.
Which gives error as
Cannot convert value of type '() -> ()' to expected argument type '((URLSessionDataTask, Any?) -> Void)?'
I don't understand how to solve this to work as per swift 3.
And there is also same like error in Facebook login.
Which gives error as
Cannot convert value of type '(FBSDKLoginManagerLoginResult!, NSError!) -> Void' to expected argument type 'FBSDKLoginManagerRequestTokenHandler!'
and
Cannot convert value of type '(_, _, NSError!) -> Void' to expected argument type 'FBSDKGraphRequestHandler!'
This all errors are related to handler blocks in swift 3. I don't understand the errors and so that can't able to solve. Any help will be appreciated. Thanks in advance.
For facebook - the problem is in new Swift rules about converting objective-c function parameters into Swift.
Previously, if parameters in objective-c code did not have nullability attributes(like nonnull or nullable), Swift converts it with ! making them non optional(forced unwrapping). Now it convert it with ? making them optional. That why you are getting an error. Before you were putting as a callback for login:
(FBSDKLoginManagerLoginResult!, NSError!) -> Void
Now you need to put:
(FBSDKLoginManagerLoginResult?, Error?) -> Void
Also, as you see, now you will not see NSError class. Instead of that Swift will put Error.This is also new rule. Now all "NS" prefixed in class names is removed in Swift(NSObject -> Object; NSError -> Error).
Example of working code for facebook login in Swift 3.0:
let manager = FBSDKLoginManager()
manager.logIn(withReadPermissions: ["public_profile"], from: self.controller) {
(loginResult: FBSDKLoginManagerLoginResult?, error: Error?) in
}
Example of working code for facebook request in Swift 3.0:
let request = FBSDKGraphRequest()
request.start {
(connection: FBSDKGraphRequestConnection?, result: Any?, error: Error?) in
}
As you see, now it is using Any type instead of objective-c id. In Swift 2.2 it was using AnyObject. It is also new Swift converting rule.
You do not need to specify callback parameters type. I did that in code for highlighting their real types. So you can just write code without them:
let manager = FBSDKLoginManager()
manager.logIn(withReadPermissions: ["public_profile"], from: self.controller) { (loginResult, error) in }
let request = FBSDKGraphRequest()
request.start { (connection, result, error) in }
But you need to remember that they are optional now.
In conclusion some converting rules that may affect you callback code:
Closure parameters are optional if in objective-c are not specified nullability attributes
All "NS" prefixes is removed for objective-c classes in Swift
If objective-c function had id parameter, in Swift 3.0 it will have type Any instead of AnyObject
Though I didn't know the error before that what Xcode want to inform me about the error, but I have removed type specification with object and it worked.
As
manager.post(methodname, parameters: param, progress: nil, success:{ (dataTask, responseObj) in
if let dict : NSDictionary = responseObj as? NSDictionary {
print("Response of \(methodname) : \(dict)")
if dict.object(forKey: "response") as? String == "success" {
CompletionHandler(true, dict)
} else {
CompletionHandler(false, dict)
}
}
})
Here with respect to question error is given at dataTask and responseObj which are with type specified. After removing type it worked fine.
Same as with facebook login
#IBAction func fbLoginClicked(_ sender: AnyObject) {
let app = UIApplication.shared.delegate as! AppDelegate
app.fbLoginManager = FBSDKLoginManager()
app.fbLoginManager.logOut()
app.fbLoginManager.loginBehavior = FBSDKLoginBehavior.native
app.fbLoginManager.logIn(withReadPermissions: ["email"], from: self, handler: { (result, error) -> Void in
if error != nil {
print(error?.localizedDescription)
} else {
if (result! as FBSDKLoginManagerLoginResult).isCancelled == true {
} else {
self.fetchFacebookUserDetail()
}
}
})
}
Here also I have removed type specification of result and error and problem solved. And followed this in whole app and it worked. I can run the project without error and also it is working. Thanks.
I am trying to call a swift method, which is implemented like this:-
#objc class DataAPI: NSObject {
func makeGet(place:NSString , completionHandler: (String! , Bool!) -> Void)
{
var str:String = ""
let manager = AFHTTPSessionManager()
manager.GET("https://api.com", parameters: nil, success:
{ (operation, responseObject) -> Void in
str = "JSON: \(responseObject!.description)"
print(str)
completionHandler(str,false) //str as response json, false as error value
},
failure: { (operation,error: NSError!) in
str = "Error: \(error.localizedDescription)"
completionHandler("Error",true)
})
}}
Now when I am trying to call it in my Objective C class, it is throwing an error "No Visible interface for DataAPI declares selector makeGet:completionHandler"
This is how I am calling the method in my Objective C class:-
[[DataAPI new] makeGet:#"" completionHandler:^{
}];
Try to clean and Rebuild to generate the "YourModule-Swift.h" again with all your changes.
Then it should be something like this:
[[DataAPI new] makeGet:#"" withCompletionHandler:^(NSString* string, BOOl b){
// your code here
}];
If you still getting that error, your "YourModule-Swift.h" file hasn't been generated correctly. Check it!
I see that in Swift the completion handler has two arguments: String and Bool whereas in your Objective-C call you pass a block without any arguments. I think it may be the cause of the error.
Try:
[[DataAPI new] makeGet:#"" completionHandler:^(NSString* string, BOOl b){
}];
You shouldn't use !(ImplicitUnwrappedOptional) keyword in closure. That is not allow bridging to ObjC code. just remove ! from closure.
func makeGet(place:NSString , completionHandler: (String! , Bool!) -> Void)
to
func makeGet(place:NSString , completionHandler: (String , Bool) -> Void)