SWIFT ToDo 应用程序 fatal error : unexpectedly found nil while unwrapping an Optional value

Question

@IBAction func btnAddTask_Click(sender: UIButton){
    taskMgr.addTask(txtTask.text , desc: txtDesc.text)
    self.view.endEditing(true)
    txtTask.text = ""
    txtDesc.text = ""
    self.tabBarController!.selectedIndex = 0

fatal error :在解包可选值时意外发现 nil(lldb)

请帮我找出问题所在。谨致问候!

Answer 1

import UIKit


var taskMgr: TaskManager = TaskManager ()
struct task
{
    var name = "Un-Named"
    var desc = "Un-Described"
}


class TaskManager: NSObject {

    var tasks = [task  ] ()
    func addTask (name: String, desc: String){
        tasks.append(task(name: name, desc: desc))

    }
}