【发布时间】：2015-06-14 17:58:47
【问题描述】：
Stack上有很多关于这个问题的问题，但似乎没有一个能解决我遇到的问题。
我在我的应用程序的登录和注册部分使用 ParseUI。我希望希望在用户（例如）未在用户名和密码字段中输入任何文本时显示UIAlertController。
这是我的MasterViewController的代码：
class MasterViewController: UIViewController, PFLogInViewControllerDelegate,
PFSignUpViewControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
if (PFUser.currentUser() == nil) {
var logInViewController = LoginViewController()
logInViewController.delegate = self
var signUpViewController = SignUpViewController()
signUpViewController.delegate = self
logInViewController.signUpController = signUpViewController
self.presentViewController(logInViewController, animated: true, completion: nil)
}
}
func logInViewController(logInController: PFLogInViewController,
shouldBeginLogInWithUsername username: String, password: String) -> Bool {
if (!username.isEmpty || !password.isEmpty) {
return true
} else {
let alertController = UIAlertController(title: "Failed to login.",
message: "Login Failure. Please try again.", preferredStyle: .Alert)
let defaultAction = UIAlertAction(title: "OK", style: .Default, handler: nil)
alertController.addAction(defaultAction)
self.presentViewController(alertController, animated: true, completion: nil)
return false
}
}
func logInViewController(logInController: PFLogInViewController,
didFailToLogInWithError error: NSError?) {
println("Failed to log in.")
}
func signUpViewController(signUpController: PFSignUpViewController,
shouldBeginSignUp info: [NSObject : AnyObject]) -> Bool {
if let password = info["password"] as? String {
return count(password.utf16) >= 8
} else {
return false
}
}
func signUpViewController(signUpController: PFSignUpViewController,
didFailToSignUpWithError error: NSError?) {
println("Failed to sign up.")
}
func logInViewController(logInController: PFLogInViewController,
didLogInUser user: PFUser) {
let installation = PFInstallation.currentInstallation()
installation["user"] = PFUser.currentUser()
installation.saveInBackground()
self.dismissViewControllerAnimated(true, completion: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func signUpViewControllerDidCancelSignUp(signUpController:
PFSignUpViewController) {
println("User dismissed signup.")
}
}
在阅读了另一个用户的答案后，我在我的工作区中添加了以下类：
import Foundation
class AlertHelper: NSObject {
func showAlert(fromController controller: MasterViewController) {
var alert = UIAlertController(title: "abc", message: "def", preferredStyle: .Alert)
controller.presentViewController(alert, animated: true, completion: nil)
}
}
然后相应地修改了我的方法：
func logInViewController(logInController: PFLogInViewController, shouldBeginLogInWithUsername 用户名：String，密码：String) -> Bool {
if (!username.isEmpty || !password.isEmpty) {
return true
} else {
let alertController = UIAlertController(title: "Failed to login.",
message: "Login Failure. Please try again.", preferredStyle: .Alert)
let defaultAction = UIAlertAction(title: "OK", style: .Default, handler: nil)
alertController.addAction(defaultAction)
var alert = AlertHelper()
alert.showAlert(fromController: self)
return false
}
}
在这一点上，我不太确定还能做什么。我的一个想法是以编程方式将UILabel 添加到我的LoginViewController 和SignUpViewController 并根据用户登录和注册的错误（或缺少错误）更改内容，但我想收到警报。
编辑：这是我的LoginViewController 中的代码。它子类化以自定义外观。我的SignUpViewController 的代码几乎相同。
导入 UIKit 导入解析 导入 ParseUI
class LoginViewController: PFLogInViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = ckPurple
let label = UILabel()
label.textColor = UIColor.whiteColor()
label.text = "Welcome."
label.sizeToFit()
logInView?.logo = label
// Do any additional setup after loading the view.
}
【问题讨论】：
标签： ios objective-c swift parse-platform ios8