Question

我正在尝试创建可滚动的imageview。目前使用的是swift 4.0。在跑步的同时我得到了＃34;没有初始化者＆＃34;错误。我不确定是什么代码带来了这个错误。我是swift的新手，我无法追踪发生的事情。

Class 'ProductDetailViewController' has no initializers我收到此错误。

任何人都可以告诉我如何修复此错误。

下面给出了整个视图控制器代码。提前致谢

import UIKit
import SwiftyJSON
class ProductDetailViewController: UIViewController,UIScrollViewDelegate {

    //Outlers
    @IBOutlet weak var scrollView: UIScrollView!

    //Global variables
    var productDict : JSON = []
    var arrayOfProductImageUrls :  Array<Any> = []
    var zoomScroll : UIScrollView

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        self.initialSetup()
        self.scrollViewSetup()
    }

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


    /*
    // MARK: - Navigation

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




    //Mark: - Scrollview Setup

    func initialSetup() {
        self.scrollView.delegate = self
    }

    func scrollViewSetup() {

        let productsArray : Array = self.arrayOfProductImageUrls;
        self.scrollView.backgroundColor = UIColor.white

        var frame : CGRect = CGRectMake(0, 0, self.scrollView.frame.size.width, 360)

        for (index, value) in productsArray.enumerated() {

            //Imageview Setup
            let productImageView : UIImageView
            let width : NSInteger = Int(frame.width)
            productImageView.frame.origin.x = CGFloat(Int (width * index))
            productImageView.frame.origin.y = 0

            //Scrollview Setup
            zoomScroll.frame = frame;
            zoomScroll.backgroundColor = UIColor.clear
            zoomScroll.showsVerticalScrollIndicator = false
            zoomScroll.showsHorizontalScrollIndicator = false
            zoomScroll.delegate = self
            zoomScroll.minimumZoomScale = 1.0
            zoomScroll.maximumZoomScale = 6.0
            zoomScroll.tag = index
            zoomScroll.isScrollEnabled = true




            self.scrollView.addSubview(zoomScroll)


            //Setting image
            let imageUrl : URL =  (productsArray[index] as AnyObject).url
            productImageView.sd_setImage(with: imageUrl)

            if index < productsArray.count {

                productImageView.frame = zoomScroll.bounds
                productImageView.contentMode = UIViewContentMode.redraw
                productImageView.clipsToBounds = true
                productImageView.backgroundColor = UIColor.clear
                zoomScroll.addSubview(productImageView)

            }

            self.scrollView.contentSize = CGSizeMake(CGFloat(frame.origin.x) + CGFloat(width), productImageView.frame.size.height)

        }

    }


    //Mark : Custom methods
    func CGRectMake(_ x: CGFloat, _ y: CGFloat, _ width: CGFloat, _ height: CGFloat) -> CGRect {
        return CGRect(x: x, y: y, width: width, height: height)
    }


    func CGSizeMake(_ width: CGFloat, _ height: CGFloat) -> CGSize {
        return CGSize(width: width, height: height)
    }

}

Answer 1

@Saurabh Prajapati。很好，快速捕获。

更多，Swift编程语言说明

类和结构必须将其所有存储属性设置为   适当的初始值，当该类的实例或   结构已创建。存储的属性不能留在   不确定的状态。

您可以在其中设置存储属性的初始值   初始化程序，或通过指定默认属性值作为一部分   财产的定义。

让我解释一下，问题在于--Recreating indexes if not exists (SELECT * FROM sys.indexes WHERE name = 'IX_SearchIndex') begin UPDATE dbo.SearchIndex SET IndexID = NEWID() CREATE UNIQUE NONCLUSTERED INDEX [IX_SearchIndex] ON [dbo].[SearchIndex] ([IndexID]) if (SELECT count(*) from sys.fulltext_catalogs where serverproperty('isfulltextinstalled') = 1) > 0 exec sp_executesql N'CREATE FULLTEXT INDEX ON [dbo].[SearchIndex] ([Content]) KEY INDEX [IX_SearchIndex]' end else Begin if (SELECT count(*) from sys.fulltext_catalogs where serverproperty('isfulltextinstalled') = 1) > 0 if not exists (SELECT * FROM sys.fulltext_indexes f INNER JOIN sys.indexes i on f.Unique_Index_id = i.Index_id and i.object_id=f.object_id Where f.object_id = object_id('SearchIndex') and i.name = 'IX_SearchIndex') exec sp_executesql N'CREATE FULLTEXT INDEX ON [dbo].[SearchIndex] ([Content]) KEY INDEX [IX_SearchIndex]' End if not exists (SELECT * FROM sys.indexes WHERE name = 'WikiRevision_UK2') begin UPDATE dbo.WikiRevision SET UID = NEWID() CREATE UNIQUE NONCLUSTERED INDEX [WikiRevision_UK2] ON [dbo].[WikiRevision] ([UID]) if (SELECT count(*) from sys.fulltext_catalogs where serverproperty('isfulltextinstalled') = 1) > 0 exec sp_executesql N'CREATE FULLTEXT INDEX ON [dbo].[WikiRevision] ([PlainText]) KEY INDEX [WikiRevision_UK2]' end else Begin if (SELECT count(*) from sys.fulltext_catalogs where serverproperty('isfulltextinstalled') = 1) > 0 if not exists (SELECT * FROM sys.fulltext_indexes f INNER JOIN sys.indexes i on f.Unique_Index_id = i.Index_id and i.object_id=f.object_id Where f.object_id = object_id('WikiRevision') and i.name = 'WikiRevision_UK2') exec sp_executesql N'CREATE FULLTEXT INDEX ON [dbo].[WikiRevision] ([PlainText]) KEY INDEX [WikiRevision_UK2]' End GO --Recreation System Procedures if exists(select * from sys.objects where object_id = object_id('dbo.pp_EnableFullText') and objectproperty(object_id,'IsProcedure')=1) drop proc dbo.pp_EnableFullText go CREATE PROCEDURE dbo.pp_EnableFullText AS if not exists (SELECT * FROM sys.indexes WHERE name = 'IX_SearchIndex') begin UPDATE dbo.SearchIndex SET IndexID = NEWID() CREATE UNIQUE NONCLUSTERED INDEX [IX_SearchIndex] ON [dbo].[SearchIndex] ([IndexID]) if (SELECT count(*) from sys.fulltext_catalogs where serverproperty('isfulltextinstalled') = 1) > 0 exec sp_executesql N'CREATE FULLTEXT INDEX ON [dbo].[SearchIndex] ([Content]) KEY INDEX [IX_SearchIndex]' end if not exists (SELECT * FROM sys.indexes WHERE name = 'WikiRevision_UK2') begin UPDATE dbo.WikiRevision SET UID = NEWID() CREATE UNIQUE NONCLUSTERED INDEX [WikiRevision_UK2] ON [dbo].[WikiRevision] ([UID]) if (SELECT count(*) from sys.fulltext_catalogs where serverproperty('isfulltextinstalled') = 1) > 0 exec sp_executesql N'CREATE FULLTEXT INDEX ON [dbo].[WikiRevision] ([PlainText]) KEY INDEX [WikiRevision_UK2]' end GO if exists(select * from sys.objects where object_id = object_id('dbo.pp_DisableFullText') and objectproperty(object_id,'IsProcedure')=1) drop proc dbo.pp_DisableFullText go CREATE PROCEDURE dbo.pp_DisableFullText AS if exists(SELECT * FROM sys.fulltext_indexes fi JOIN sys.indexes i ON i.[object_id] = fi.[object_id] AND i.[name] = 'IX_SearchIndex') exec sp_executesql N'DROP FULLTEXT INDEX ON [dbo].[SearchIndex]' if exists(select * from sys.indexes where name = 'IX_SearchIndex') DROP INDEX [IX_SearchIndex] ON [dbo].[SearchIndex] if exists(SELECT * FROM sys.fulltext_indexes fi JOIN sys.indexes i ON i.[object_id] = fi.[object_id] AND i.[name] = 'WikiRevision_UK2') exec sp_executesql N'DROP FULLTEXT INDEX ON [dbo].[WikiRevision]' if exists(select * from sys.indexes where name = 'WikiRevision_UK2') DROP INDEX [WikiRevision_UK2] ON [dbo].[WikiRevision] GO属性没有默认值。如上所述，Swift中的所有变量必须始终具有值或nil（使其成为可选）。当你使它成为可选项时，你默认允许它为零，不需要显式给它一个值或初始化它。

此处我们使用scrollView可选，因此默认值为!

nil

将nil设置为默认值

class ViewController : UIViewController {
    @IBOutlet weak var scrollView: UIScrollView!
}

设置默认值，现在创建一个对象，它不是零。

class ViewController : UIViewController {
    @IBOutlet weak var scrollView: UIScrollView! = nil
}

但是我们不能这样做，我们没有在这里设置默认值。

class ViewController : UIViewController {
    @IBOutlet weak var scrollView: UIScrollView = UIScrollView()
}

我希望它会有所帮助。

Answer 2

我有同样的回音通过使用它很容易解决它！在像这样的任何变量之后 var ref：DatabaseReference！

Class＆＃39; ProductDetailViewController＆＃39;没有初始化者

2 个答案: