i am learning to build collectionView the modern way for a few weeks now, and i am constantly facing issue to overcome and solve, but i am making no progress with this one here at all..

var layoutConfig = UICollectionLayoutListConfiguration(appearance: .plain)
        layoutConfig.trailingSwipeActionsConfigurationProvider = { indexPath in
            
            let commentIDString = self.dataSource.itemIdentifier(for: indexPath)?.commentID
            let commentID = Int32(commentIDString ?? 0)
            
            let action = UIContextualAction(style: .destructive, title: "", handler: {(action, view, completion) in
                print("swipe action triggered!?")
                Task {
                    do{
                        let parameter = ["commentID": commentID, "action": "removeComment"]       // remove Comment
                        let returnDictionary = await APIs.shared.contactAPI(urlString: "APIURL.comments.php", parameter: parameter)
                    }
                }
                
                
                completion(true)
            })
            action.image = UIImage(systemName: "delete.left")
            action.backgroundColor = .systemRed
            return UISwipeActionsConfiguration(actions: [action])
        }

contactAPI:

func contactAPI(urlString: String, parameter: Dictionary<String,String>) async -> Dictionary<String, Any> {

        let encoder = JSONEncoder()
        encoder.outputFormatting = .prettyPrinted
        var jsonData = Data()
        do { jsonData = try encoder.encode(parameter) }
        catch let error { print("something went wrong here -.-: \(error)") }
        print(String(data: jsonData, encoding: .utf8)!) // for debugging
        
        let url = URL(string: urlString)
        var request = URLRequest(url: url!)
        request.httpMethod = "POST"
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        
        let (data, _) = try! await URLSession.shared.upload(for: request, from: jsonData)
        
        //// for debugging
//        let dataString = String(data: data, encoding: .utf8)
//        print(dataString)
        
        let dictionary: [String: String] = try! JSONDecoder().decode([String: String].self, from: data)
//        print(dictionary)   // for debugging
//        var returnDic = Dictionary<String, Any>()
        
        return dictionary
    }

as you can see i have to call a network method inside that actionHandler, and xcode is complaining that the "trailingSwipeActionsConfigurationProvider": "Type of expression is ambiguous without more context"

if i remove that Task {} Block, everythings works as expected, so as i understood it there is a problem with that API call which of course is async, and can't find any documentation about that anywhere ..please help me out guys

CodePudding user response：

The compiler is complaining as it does not know how to interpret your code. The do block has to be followed by a catch block in swift.

Task {
    let parameter = ["commentID": commentID, "action": "removeComment"]       // remove Comment
    let returnDictionary = await APIs.shared.contactAPI(urlString: "APIURL.comments.php", parameter: parameter)
}

I have to admit I didn´t test this answer thoroughly. Sorry for that. It just seemed to be the most obvious error.

After disecting your code I found the issue:

Take a look at your functions signature

func contactAPI(urlString: String, parameter: Dictionary<String,String>) async -> Dictionary<String, Any> {

and the way you construct your argument

let commentID = Int32(commentIDString ?? 0)
    
let parameter = ["commentID": commentID, "action": "removeComment"]       // remove Comment
let returnDictionary = await APIs.shared.contactAPI(urlString: "APIURL.comments.php", parameter: parameter)

parameter is a [String:Any] here because commentID is of type Int and the next value is of type String. Anyway your function expects [String:String].

You need to fix this. It seems the best approach would be to create a custom struct for your parameters and encode that instead of this clumpsy dictionary approach.

Without knowing more about your code structure and needs for parameter I would recommend this struct:

struct Parameter: Codable{
    var commentID: Int
    var action: String
}


let commentIDString = self.dataSource.itemIdentifier(for: indexPath)?.commentID
let commentID = Int(commentIDString ?? "0") ?? 0

let action = UIContextualAction(style: .destructive, title: "", handler: {(action, view, completion) in
    print("swipe action triggered!?")
    
    Task {
            let parameter = Parameter(commentID: commentID, action: "removeComment")      // remove Comment
            let responseDict = await APIs.shared.contactAPI(urlString: "APIURL.comments.php", parameter: parameter)
    }


    completion(true)
})

The signature of your function would become:

func contactAPI(urlString: String, parameter: Parameter) async -> Dictionary<String, String> {

This should work this way. By the way, your String? to Int conversion was also flawed and would have thrown another error.