ios - POST 请求后 self.present 不起作用

Question

我正在尝试创建一个带有服务器连接的页面。

一个简单的 POST(电子邮件和密码字段)，在响应时，我需要向用户显示一个警报。

这一行导致异常:

self.present(alerta2, animated:true, completion:nil)

这是我的代码:

request.httpMethod = "POST" // Compose a query string
let postString = "email=" + userEmail + "&password=" + userPassword
request.httpBody = postString.data(using: String.Encoding.utf8)
let task = URLSession.shared.dataTask(with: request) { (data: Data?, response: URLResponse?, error: Error?) in
    if error != nil {
        self.mostraAlerta(mensagem: "Ocorreu um erro!")
        return
    }

    // Let's convert response sent from a server side script to a NSDictionary object:
    do {
        let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
        // print(json)
        if let parseJSON = json {
            let status = parseJSON["status"] as? String
            let msg = parseJSON["msg"] as? String
            let titulo = parseJSON["titulo"] as? String
            switch status {
            case "0"?:
                let alerta2 = UIAlertController(title: titulo, message: msg!, preferredStyle: .alert)
                let okAction = UIAlertAction(title: "OK", style: .default) { action in
                    self.dismiss(animated: true, completion: nil)
                }
                alerta2.addAction(okAction)
                self.present(alerta2, animated: true, completion: nil)
                // print("Status: OK")
                break
            case "1"?:
                print("Status: " + msg!)
                break
            default:
                print("Status: N/D")
                break
            }
            // print("Status: \(status)")
        }
    } catch {
        print(error)
    }
}
task.resume()

异常:

错误:

libsystem_kernel.dylib`__pthread_kill: 0x110b48d38
<+0>: movl $0x2000148, %eax ; imm = 0x2000148 0x110b48d3d
<+5>: movq %rcx, %r10 0x110b48d40
<+8>: syscall -> 0x110b48d42
<+10>: jae 0x110b48d4c ; <+20> 0x110b48d44
<+12>: movq %rax, %rdi 0x110b48d47
<+15>: jmp 0x110b41caf ; cerror_nocancel 0x110b48d4c
<+20>: retq 0x110b48d4d
<+21>: nop 0x110b48d4e
<+22>: nop 0x110b48d4f
<+23>: nop

Answer 1

我刚得到错误和修复。

错误:

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[UIKeyboardTaskQueue waitUntilAllTasksAreFinished] may only be called from the main thread.

解决方法:

OperationQueue.main.addOperation {
    self.present(alerta2, animated:true, completion:nil)
}