ios - 没有更多上下文swift4，表达式类型不明确

Question

我得到的错误是:

"Type of expression is ambiguous without more context swift4"

我正在为 iPhone 应用程序制作本地通知提醒页面。我正在使用 Xcode 9 和 Swift 4。

import UIKit
@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate 
{
    var window: UIWindow?

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject : AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        if(UIApplication.instancesRespond(to: Selector("registerUserNotificationSettings:"))) {
            UIApplication.sharedApplication.registerUserNotificationSettings(UIUserNotificationSettings(forTypes: .Alert | .Badge, categories: nil))
        }

        return true
    }

    func application(_ application: UIApplication, didReceive notification: UILocalNotification) {
        application.applicationIconBadgeNumber = 0
    }

Answer 1

您遇到的问题是因为代码的语法不正确。您在此处发布的代码位于 Swift-2 中，这就是它给您语法错误的原因。

在 Swift-4 中使用以下代码:

UIApplication.shared.registerUserNotificationSettings(UIUserNotificationSettings.init(types: [.alert, .badge], categories: nil))

如果您仍然遇到任何问题，请告诉我。