如何将数据从Realm传递给ViewController

Question

我在swift 2.3，xcode 7.3.1开设了新闻应用。我有Realm DB和服务器中的数据。当我按下按钮并显示所选数据（新闻）时，我需要移动到ViewController。按钮由我的新闻元素组成。如何从选定的新闻元素传递数据以显示另一个ViewController的详细信息？

这是新闻元素。具有水平滚动元素的按钮：

这是代码：

import UIKit
import RealmSwift

let realm4 = try! Realm()

class MainViewController: UIViewController, HorizontalScrollDelegate {

let newsObj = realm4.objects(News)
let nObj = News()

var imageURL: NSURL?

override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
    super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
}

override func viewDidLoad() {
    super.viewDidLoad()

    let hScroll = HorizontalScroll(frame: CGRectMake(0, 0, 380, 160))
    hScroll.delegate = self
    hScroll.backgroundColor = UIColor.whiteColor()
    self.view.addSubview(hScroll)
    view.reloadInputViews()

}
   func numberOfScrollViewElements() -> Int {
        return newsObj.count
    }

    func elementAtScrollViewIndex(index: Int) -> UIView {

        let indexes = newsObj[index]

        let view = UIView(frame: CGRectMake(5.0, 0.0, 200.0, 200.0))
        var imageView = UIImageView()
        let imageLabel = UIImageView()
        let newsLable = UILabel()
        let button = UIButton()

        var image: UIImage? {

            get { return imageView.image }
            set {
                imageView.image = newValue
                imageView.sizeToFit()
            }
        }

        newsLable.text = indexes.newsTitle

        imageURL = NSURL(string: indexes.newsImage)

        if let url = imageURL {
            let imageData = NSData(contentsOfURL: url)
            if imageData != nil {
                image = UIImage(data: imageData!)
            }
        }

        newsLable.lineBreakMode = .ByWordWrapping
        newsLable.font = UIFont(name: "Roboto-Bold", size: 18)
        newsLable.textColor = UIColor.whiteColor()
        newsLable.frame = CGRectMake(7.0, 90.0, 200.0, 50.0)
        newsLable.textAlignment = .Left
        newsLable.numberOfLines = 0

        button.frame = CGRectMake(0.0, 0.0, 200.0, 200.0)
        button.addTarget(indexes, action: #selector(tapAction2), forControlEvents: .TouchUpInside)
        print("This is 1 nObj \(self.nObj)")

        imageLabel.backgroundColor = UIColor.blackColor()
        imageLabel.alpha = 0.45
        imageLabel.frame = CGRectMake(5.0, 90.0, 200.0, 65.0)
        imageView.frame = view.frame

        view.addSubview(imageView)
        view.addSubview(imageLabel)
        view.addSubview(newsLable)
        view.addSubview(button)

        return view
    }

func tapAction2(index: Int) {
    print("This is func INDEX \(index)")
    //let segueIndex = index
    let storyBoard = UIStoryboard(name: "Main", bundle: nil)
    let newView = storyBoard.instantiateViewControllerWithIdentifier("NewsDetailViewController") as! NewsDetailViewController
    newView.modalPresentationStyle = UIModalPresentationStyle.Custom
    print("This is nObj \(self.nObj)")
    print("This is INDEX \(index)")
    newView.newsOfTitle = String(index)
    presentViewController(newView, animated: true, completion: nil)
}
}

我尝试使用索引传递数据。但在控制台我有空数据。可能是Realm的问题。 在控制台中我看到了

  

这是INDEX 140659923446288

但我的项目中没有这个数据

这是我的Realm DB

Answer 1

如UIButton Class Reference所述，动作方法的签名采用三种形式之一

@IBAction func doSomething()
@IBAction func doSomething(sender: UIButton)
@IBAction func doSomething(sender: UIButton, forEvent event: UIEvent)

但不是func doSomething(index: Int)。

这就是你在方法中得到错误索引的原因。