无法在swift中更改UIButton上的文本

Question

所以，我对XCode和Swift很新。我在更改UIButton上的标题文本时遇到问题，并且我一直收到错误

  

    

致命错误：在解包可选值时意外发现nil

  

This is my code :
//
//  ViewController.swift
//  mtgHealthTracker
//
//  Created by Reagan McFarland on 5/1/16.
//  Copyright © 2016 Reagan McFarland. All rights reserved.
//

import UIKit

class ViewController: UIViewController {
    //Mark : Properties


    @IBOutlet weak var btnPlayer1Health: UIButton!
    @IBOutlet weak var btnPlayer4Health: UIButton!
    @IBOutlet weak var btnPlayer3Health: UIButton!
    @IBOutlet weak var btnPlayer2Health: UIButton!

    @IBOutlet weak var lblCurrWinner: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

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

    //Mark Actions
    @IBAction func btnPlayer1HealthChanged(sender: UIButton, forEvent event: UIEvent) {
        btnPlayer1Health.setTitle("Hello World", forState: UIControlState.Normal)

    }

    @IBAction func btnPlayer2HealthChanged(sender: UIButton, forEvent event: UIEvent) {
    }

非常感谢帮助！谢谢:)）

Answer 1

您的一个或多个IBOutlet未在您的XIB / Storyboard中连接。确保选择文件所有者并将IBOutlet拖到XIB / Storyboard元素中。