构建应用程序后不显示 UI 保存按钮

Posted 2023-03-10

【中文标题】构建应用程序后不显示 UI 保存按钮

【英文标题】：UIsavebutton doesnt show after built the app

【发布时间】：2020-02-14 10:44:57

【问题描述】：

这是一个壁纸应用，所以屏幕上有保存按钮，UIButton 应该保存当前显示给用户的图像。所以我已经编写了这段代码并识别了 UIButton 然后当我开始构建应用程序时，按钮没有显示出来......

这是我的代码

class ViewController: UIViewController 

    // app parameters

    @IBOutlet weak var imageView: UIImageView!

    @IBOutlet weak var saveButton: UIButton!

    //when tapped
    @IBAction func saveButtonTapped(_ sender: UIButton) 
        let success = saveImage(image: imageArray[0])
        print("Did \(success ? "" : "not ")store image successfully")
    


    //scroll view

    let scrollView: UIScrollView = 
           let scroll = UIScrollView()
           scroll.isPagingEnabled = true
           scroll.showsVerticalScrollIndicator = false
           scroll.showsHorizontalScrollIndicator = false
           scroll.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
           return scroll
       ()



    //setup images

    func setupImages(_ images: [UIImage])
           for i in 0..<images.count 
               let imageView = UIImageView()
               imageView.image = images[i]
               let xPosition = UIScreen.main.bounds.width * CGFloat(i)
               imageView.frame = CGRect(x: xPosition, y: 0, width: scrollView.frame.width, height: scrollView.frame.height)
                imageView.contentMode = .scaleAspectFit
               scrollView.contentSize.width = scrollView.frame.width * CGFloat(i + 1)
               scrollView.addSubview(imageView)

        
    

    //image array

    var imageArray = [UIImage]()



    //save image
    func saveImage(image: UIImage) -> Bool 
        guard let data = image.jpegData(compressionQuality: 1) ?? image.pngData() else 
            return false
        

        guard let directory = try? FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false) as NSURL else 
            return false
        

        do 
            try data.write(to: directory.appendingPathComponent("fileName.png")!)
            return true
         catch 
            print(error.localizedDescription)
            return false
        
    


   //did load

    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        //imageArray
        view.addSubview(scrollView)
        imageArray = [#imageLiteral(resourceName: "6"),#imageLiteral(resourceName: "9"),#imageLiteral(resourceName: "3")]
        setupImages(imageArray)
    

【问题讨论】：

试试 savebutton.bringtofront，你能展示你的故事板拱门吗

确保你的按钮在滚动视图的前面。

【参考方案1】：

试试这个！

override func viewDidLoad() 
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    //imageArray
    view.addSubview(scrollView)
    imageArray = [#imageLiteral(resourceName: "6"),#imageLiteral(resourceName: "9"),#imageLiteral(resourceName: "3")]
    setupImages(imageArray)
    scrollView.addSubview(saveButton)

【讨论】：

一条消息出来，线程 1：致命错误：在隐式展开可选值时意外发现 nil