SwiftUI-不允许发布后台线程-在不更新ui的代码上
swiftui新手,不理解为什么第一个代码中的JSONDecoder()行会抛出 [SwiftUI]不允许从后台线程发布更改;确保在模型更新时从主线程(通过诸如receive(on:)之类的操作符)发布值 这对我来说并不是在更新用户界面,为什么会出现这种情况 我尝试在SwiftUI-不允许发布后台线程-在不更新ui的代码上,swiftui,thread-safety,runtime-error,Swiftui,Thread Safety,Runtime Error,swiftui新手,不理解为什么第一个代码中的JSONDecoder()行会抛出 [SwiftUI]不允许从后台线程发布更改;确保在模型更新时从主线程(通过诸如receive(on:)之类的操作符)发布值 这对我来说并不是在更新用户界面,为什么会出现这种情况 我尝试在L.fetchData(from:request){result in中的do catch周围包装一个主队列,但这没有帮助 DispatchQueue.main.async { [weak self] in 这是登录协议,同样
L.fetchData(from:request){result in
中的do catch
周围包装一个主队列,但这没有帮助
DispatchQueue.main.async { [weak self] in
这是登录协议,同样没有任何ui工作:
import Foundation
import SwiftUI
struct Login: Endpoint {
var url: URL?
init(url: URL?) {
self.url = url
}
}
protocol Endpoint {
var url: URL? { get set }
init(url: URL?)
}
extension Endpoint {
func getRequestUrl() -> URLRequest {
guard let requestUrl = url else { fatalError() }
// Prepare URL Request Object
return URLRequest(url: requestUrl)
}
func getRequest(requestType:String="POST", token:String, email:String="", password:String="") -> URLRequest {
var request = self.getRequestUrl()
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
if ( "" != email && "" != password && requestType == "POST") {
let parameters:[String:String?] = [
"email": email,
"password": password
]
// Run the request
do {
// pass dictionary to nsdata object and set it as request body
request.httpBody = try JSONSerialization.data(withJSONObject: parameters, options: .prettyPrinted)
} catch let error {
print(error.localizedDescription)
}
}
return request;
}
func fetchData(from request: URLRequest, completion: @escaping (Result<Data, NetworkError>) -> Void) {
URLSession.shared.dataTask(with: request) { data, response, error in
if let data = data {
completion(.success(data))
} else if error != nil {
// any sort of network failure
completion(.failure(.requestFailed))
} else {
// this ought not to be possible, yet here we are
completion(.failure(.unknown))
}
}.resume()
}
}
extension URLSession {
func dataTask(with request: URLRequest, completionHandler: @escaping (Result<(Data, HTTPURLResponse), Error>) -> Void) -> URLSessionDataTask {
return dataTask(with: request, completionHandler: { (data, urlResponse, error) in
if let error = error {
completionHandler(.failure(error))
} else if let data = data, let urlResponse = urlResponse as? HTTPURLResponse {
completionHandler(.success((data, urlResponse)))
}
})
}
}
<代码>导入基础
导入快捷键
结构登录:端点{
var-url:url?
初始化(url:url?){
self.url=url
}
}
协议端点{
var url:url?{get set}
初始化(url:url?)
}
扩展端点{
func getRequestUrl()->URLRequest{
guard let requestUrl=url else{fatalError()}
//准备URL请求对象
返回url请求(url:requestUrl)
}
func getRequest(requestType:String=“POST”,token:String,email:String=“”,password:String=“”)->URLRequest{
var request=self.getRequestUrl()
request.httpMethod=“POST”
request.setValue(“application/json”,forHTTPHeaderField:“Content Type”)
request.addValue(“承载者\(令牌)”,用于HttpHeaderField:“授权”)
如果(“!=email&&”!=password&&requestType==“POST”){
let参数:[字符串:字符串?]=[
“电子邮件”:电子邮件,
“密码”:密码
]
//运行请求
做{
//将字典传递给nsdata对象并将其设置为请求正文
request.httpBody=try JSONSerialization.data(带jsonObject:参数,选项:。预打印)
}捕捉错误{
打印(错误。本地化描述)
}
}
返回请求;
}
func fetchData(从请求:URLRequest,完成:@escaping(Result)->Void){
URLSession.shared.dataTask(with:request){data,response,中的错误
如果let data=data{
完成(.success(数据))
}否则,如果错误!=nil{
//任何类型的网络故障
完成(.failure(.requestFailed))
}否则{
//这不应该是可能的,但我们现在在这里
完成(.failure(.unknown))
}
}1.简历()
}
}
扩展URL会话{
func dataTask(带请求:URLRequest,completionHandler:@escaping(Result)->Void)->URLSessionDataTask{
在中返回dataTask(带有:request,completionHandler:{(数据,urlResponse,error)
如果let error=error{
completionHandler(.failure(error))
}否则,如果让data=data,则让urresponse=urresponse作为?httpurresponse{
completionHandler(.success((数据,urlResponse)))
}
})
}
}
你知道如何解决这个问题吗?把它包装起来,代替作业
catch {
DispatchQueue.main.async {
self.error = error.localizedDescription
}
}
case .failure(let error):
DispatchQueue.main.async {
self.error = error.localizedDescription
}
}
什么是
self.error
?@Published var error:String=”“谢谢@Asperi,这就成功了。我想知道为什么现在会出现这种情况,因为我已经运行这样的代码好几个星期了。是不是因为self.error在视图上绑定的太不经意了,虽然它不是直接的ui更新,但它是更新ui的绑定?
catch {
DispatchQueue.main.async {
self.error = error.localizedDescription
}
}
case .failure(let error):
DispatchQueue.main.async {
self.error = error.localizedDescription
}
}