在Swift中读取UIApplicationLaunchOptionsURLKey
只想阅读Swift中的启动选项。
这是我的旧obj-C代码，工作正常：
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { NSURL *URL = [launchOptions valueForKey:UIApplicationLaunchOptionsURLKey]; if (URL) 这就是我认为Swift代码应该是这样的：
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { if let options = launchOptions { let URL: NSURL = options(UIApplicationLaunchOptionsURLKey) as String
但它给出了错误：
‘（NSString！） – > $ T2’与'[NSObject：AnyObject]’不同
铸造错误？ 但难以正确地进行铸造而无法找到如何做到这一点的链接。
斯威夫特3：
在Swift 3中， launchOptions是一个类型为[UIApplicationLaunchOptionsKey: Any]?的字典[UIApplicationLaunchOptionsKey: Any]? ，所以你可以像这样访问这个值：
launchOptions?[UIApplicationLaunchOptionsKey.url]
由于密钥类型是UIApplicationLaunchOptionsKey ，因此您可以将enum类型简称为.url ：
launchOptions?[.url]
与该键关联的值是URL ，而不是String 。 此外，键可能不存在于字典中，因此您应该使用条件转换as? 而不是正常的铸造。
在Swift中，您想要：
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool { if let url = launchOptions?[.url] as? URL { // If we get here, we know launchOptions is not nil, we know // key .url was in the launchOptions dictionary, and we know // that the type of the launchOptions was correctly identified // as URL. At this point, url has the type URL and is ready to use. }
斯威夫特2：
在您的代码中， launchOptions是一个类型为[NSObject: AnyObject]?的字典[NSObject: AnyObject]? ，所以你想要访问这样的值：
options?[UIApplicationLaunchOptionsURLKey]
与该键关联的值是NSURL ，而不是String 。 此外，键可能不存在于字典中，因此您应该使用条件转换as? 而不是正常的铸造。
在Swift中，您想要：
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { if let url = launchOptions?[UIApplicationLaunchOptionsURLKey] as? NSURL { // If we get here, we know launchOptions is not nil, we know // UIApplicationLaunchOptionsURLKey was in the launchOptions // dictionary, and we know that the type of the launchOptions // was correctly identified as NSURL. At this point, url has // the type NSURL and is ready to use. }