应用程序卡在启动画面上

Question

我的应用程序在运行时卡在启动画面上。它已经有一个storyboard入口点，它指向名为studentsViewController的视图控制器，所以我不知道为什么它不起作用。没有崩溃。 StudentsViewController：

 import UIKit
class StudentsViewController: UIViewController, UITableViewDelegate,     UITableViewDataSource {

@IBOutlet weak var tableView: UITableView!

var currentClass = VirtualRewardsClient.sharedInstance.getClass()

override func viewDidLoad() {
    super.viewDidLoad()
    tableView.dataSource = self
    tableView.delegate = self
   tableView.registerClass(StudentTableViewCell.self, forCellReuseIdentifier: "studentCell")
    Class.sharedInstance.addStudent("Dhruv")
    Class.sharedInstance.printClass()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return Class.sharedInstance.students.count
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = self.tableView.dequeueReusableCellWithIdentifier("studentCell") as StudentTableViewCell
    return cell
}
/*
// MARK: - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    // Get the new view controller using segue.destinationViewController.
    // Pass the selected object to the new view controller.
}
*/
}

VirtualRewardsClient.swift

import UIKit

class VirtualRewardsClient{

class var sharedInstance: VirtualRewardsClient{
    struct Static{
        static var instance = VirtualRewardsClient()
    }
    return Static.instance
}

func getClass() -> Class{

    if let data = NSUserDefaults.standardUserDefaults().objectForKey(classKey) as? NSData{
        let unarc = NSKeyedUnarchiver(forReadingWithData: data)
        unarc.setClass(Class.self, forClassName: "Class")
        let currentClass = unarc.decodeObjectForKey("root") as Class
        Class.sharedInstance.students = currentClass.students
        Class.sharedInstance.teacher = currentClass.teacher
        return currentClass

    }
    return Class()
}
}

Class.swift

import Foundation

导入UIKit

让classKey =“CLASS_KEY”

class Class：NSObject {     let defaults = NSUserDefaults.standardUserDefaults（）

class var sharedInstance: Class{
    struct Static{
        static var instance: Class = VirtualRewardsClient.sharedInstance.getClass()
    }
    return Static.instance
}
var students:[Student] = [Student]()
var teacher = Teacher(currentClass: sharedInstance)

func addStudent(name: String, value: Int){
    students.append(Student(name: name, startingPoints: value))
    defaults.setObject(NSKeyedArchiver.archivedDataWithRootObject(Class.sharedInstance), forKey: classKey)
    VirtualRewardsClient.sharedInstance.getClass()
}

func addStudent(name: String){
    students.append(Student(name: name))
    defaults.setObject(NSKeyedArchiver.archivedDataWithRootObject(Class.sharedInstance), forKey: classKey)
    VirtualRewardsClient.sharedInstance.getClass()
}

func printClass(){
    for i in students{
        println("Student: \(i.name), Points: \(i.points)")
    }
}

}