IBOutlet在instantiateViewControllerWithIdentifier之后为零 [英] IBOutlet nil after instantiateViewControllerWithIdentifier

问题描述

不确定我在这里做错了什么。我列出了我的问题和我的代码。很想得到一些帮助。

Not sure exactly what I'm doing wrong here. I've listed out what my problem is and my code. Would love to get some help.

谢谢！

问题：

• VC1呈现VC2。


• 来自VC1的IBOutlets现在为零。


• VC2解散回VC1。


• VC1中的IBOutlets仍为零。

• VC1 presents VC2.
• IBOutlets from VC1 are now nil.
• VC2 dismisses back into VC1.
• IBOutlets in VC1 are still nil.

VC1从flickR加载图片网格。 VC2有一个searchBar控制器，当VC2被解雇时它会运行flickR查询。就在我的self.collectionView.reload（）失败之前，因为self.collectionView是nil :(

VC1 loads a grid of pictures from flickR. VC2 has a searchBar controller, when VC2 is dismissed it does runs flickR query. Right before my self.collectionView.reload() fails because self.collectionView is nil :(

VC1

import UIKit

class MainViewController: UIViewController, UICollectionViewDelegate,    UICollectionViewDataSource {

@IBOutlet var collectionView: UICollectionView!
@IBOutlet var searchMask: UIView!

let api_key = "f87357398a52b80e0c9f76bf94c8ee94"

var flickResults:NSMutableArray! = NSMutableArray()
var titleResults:NSMutableArray! = NSMutableArray()

override func viewDidLoad() {
    super.viewDidLoad()
     loadPhotos("Brasil")
    // Do any additional setup after loading the view.
}

override func viewDidAppear(animated: Bool) {
    super.viewDidAppear(animated)
}

func loadPhotos(searchString: String) {
    let flickr:FlickrHelper = FlickrHelper()
    println("Collection: \(self.collectionView)")
    flickr.request(searchString, per_page: 50, completion: { (searchStr, flickrPhotos, photoTitle) -> () in
        dispatch_async(dispatch_get_main_queue(), {
            self.flickResults = flickrPhotos
            self.titleResults = photoTitle
            self.collectionView.reloadData()
        })
    })
}

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

override func preferredStatusBarStyle() -> UIStatusBarStyle {
    return UIStatusBarStyle.LightContent
}


func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell: PhotoCell = self.collectionView.dequeueReusableCellWithReuseIdentifier("photoCell", forIndexPath: indexPath) as PhotoCell
    cell.photoImageView.alpha = 0
    let queue:dispatch_queue_t = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)

    dispatch_async(queue, {
        let searchURL: String = self.flickResults.objectAtIndex(indexPath.item) as String
        let title: String = self.titleResults.objectAtIndex(indexPath.item) as String
        let image: UIImage = self.loadImage(searchURL)
        dispatch_async(dispatch_get_main_queue(), {
            UIView.animateWithDuration(0.5, animations: {
                cell.photoImageView.image = image
                cell.photoTitle.text = title.capitalizedString
                cell.photoImageView.alpha = 1
            })

        })
    })

    insertBlurView(cell.titleMask, UIBlurEffectStyle.Dark)

    return cell
}

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return self.flickResults.count
}

func loadImage(imageUrl: String) -> UIImage{
    let url = NSURL(string: imageUrl)
    let data = NSData(contentsOfURL: url!)
    let image = UIImage(data: data!)
    return image!
}


@IBAction func searchButtonPressed(sender: UIButton) {
    let storyboard = UIStoryboard(name: "Main", bundle: nil);
    let vc: SearchViewController = storyboard.instantiateViewControllerWithIdentifier("Search") as SearchViewController
    providesPresentationContextTransitionStyle = true
    definesPresentationContext = true
    vc.modalPresentationStyle = UIModalPresentationStyle.OverCurrentContext
    self.presentViewController(vc, animated: false, completion: nil)

}
}

VC2

 import UIKit


 class SearchViewController: UIViewController, UITextFieldDelegate, UISearchBarDelegate, UICollectionViewDelegate {


@IBOutlet var searchMask: UIView!
@IBOutlet var searchField: UITextField!
@IBOutlet var searchBar: UISearchBar!

override func viewDidLoad() {
    super.viewDidLoad()
    insertBlurView(self.searchMask, UIBlurEffectStyle.Dark)
}

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

@IBAction func exitTap(sender: UIButton) {
    self.dismissViewControllerAnimated(true, completion: nil)
}


func searchBarSearchButtonClicked(searchBar: UISearchBar) {
    self.dismissViewControllerAnimated(true, completion: {
        let mainvc = self.storyboard?.instantiateViewControllerWithIdentifier("Main") as MainViewController
        mainvc.loadPhotos(searchBar.text)
    })
  }
}

推荐答案

感谢rdelmar，我能够使用协议来解决这个问题。

Thanks to rdelmar, I was able to figure this out using protocols.

这是我添加的内容：

• SearchDelegate


• SearchDelegate函数runSearch（）

VC1

class MainViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, SearchDelegate {  

func runSearch(searchString: String) {
    loadPhotos(searchString)
 }

}

VC2

protocol SearchDelegate {
    func runSearch(searchString: String)
 }

class SearchViewController: UIViewController, UITextFieldDelegate, UISearchBarDelegate, UICollectionViewDelegate {


@IBOutlet var searchMask: UIView!
@IBOutlet var searchField: UITextField!
@IBOutlet var searchBar: UISearchBar!

var delegate: SearchDelegate?

func searchBarSearchButtonClicked(searchBar: UISearchBar) {
    delegate?.runSearch(searchBar.text)
    self.dismissViewControllerAnimated(true, completion:nil)

}

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