如何将视图控制器中的数据传递给另一个视图控制器中的集合视图？ [复制]

Posted 2023-02-23

【中文标题】如何将视图控制器中的数据传递给另一个视图控制器中的集合视图？ [复制]

【英文标题】：How to pass data in a View Controller to a Collection View in another View Controller? [duplicate]

【发布时间】：2017-08-11 11:18:17

【问题描述】：

我正在尝试在 UITextField 中传递数据，用户将输入这些数据以进入另一个视图控制器的集合视图中的单元格。

我想在每次有人按下“上传”按钮时创建新的“帖子”以添加到我的提要中，因此“收藏视图”单元格需要以某种方式上传给定信息，然后清除该单元格。

我不知道如何将数据传递给集合视图。

这是我的视图控制器和单元格代码。

import UIKit
import Firebase

class UploadViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate 


    @IBOutlet weak var previewImage: UIImageView!
    @IBOutlet weak var postBtn: UIButton!
    @IBOutlet weak var selectBtn: UIButton!

    @IBOutlet weak var thisTextField: UITextField!


    @IBOutlet weak var thatTextField: UITextField!
    var picker = UIImagePickerController()



    @IBAction func thisPhotoUpload(_ sender: Any) 

        if thisTextField.text != "" || thatTextField.text != ""
        
            performSegue(withIdentifier: "segue", sender: self)
        

    

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) 

        var postCell = segue.destination as! PostCell

        postCell.thisString = thisTextField.text!

        postCell.thatString = thatTextField.text!
    

    override func viewDidLoad() 
        super.viewDidLoad()

        picker.delegate = self
    


    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) 
        if let image = info[UIImagePickerControllerEditedImage] as? UIImage 
            self.previewImage.image = image
            selectBtn.isHidden = true
            postBtn.isHidden = false
        

        self.dismiss(animated: true, completion: nil)
    


    @IBAction func selectPressed(_ sender: Any) 

        picker.allowsEditing = true
        picker.sourceType = .photoLibrary

        self.present(picker, animated: true, completion: nil)

    


    @IBAction func postPressed(_ sender: Any) 
        AppDelegate.instance().showActivityIndicator()

        let uid = FIRAuth.auth()!.currentUser!.uid
        let ref = FIRDatabase.database().reference()
        let storage = FIRStorage.storage().reference(forURL: "gs://instagram-f3f20.appspot.com")

        let key = ref.child("posts").childByAutoId().key
        let imageRef = storage.child("posts").child(uid).child("\(key).jpg")

        let data = UIImageJPEGRepresentation(self.previewImage.image!, 0.6)

        let uploadTask = imageRef.put(data!, metadata: nil)  (metadata, error) in
            if error != nil 
                print(error!.localizedDescription)
                AppDelegate.instance().dismissActivityIndicatos()
                return
            

            imageRef.downloadURL(completion:  (url, error) in
                if let url = url 
                    let feed = ["userID" : uid,
                                "pathToImage" : url.absoluteString,
                                "likes" : 0,
                                "author" : FIRAuth.auth()!.currentUser!.displayName!,
                                "postID" : key] as [String : Any]

                    let postFeed = ["\(key)" : feed]

                    ref.child("posts").updateChildValues(postFeed)
                    AppDelegate.instance().dismissActivityIndicatos()

                    self.dismiss(animated: true, completion: nil)
                
            )

        

        uploadTask.resume()

    

CollectionViewCell 子类

import UIKit
import Firebase

class PostCell: UICollectionViewCell 

    @IBOutlet weak var postImage: UIImageView!
    @IBOutlet weak var authorLabel: UILabel!
    @IBOutlet weak var likeLabel: UILabel!


    @IBOutlet weak var likeBtn: UIButton!
    @IBOutlet weak var unlikeBtn: UIButton!


    @IBOutlet weak var thisLabel: UILabel!
    @IBOutlet weak var thisButton: UIButton!
    @IBOutlet weak var thatLabel: UILabel!
    @IBOutlet weak var thatButton: UIButton!

    var postID: String!
    var thisString = String()
    var thatString = String()



    override func awakeFromNib() 
        super.awakeFromNib()




        thisLabel.text = thisString

        thisButton.setTitle(thisString, for: UIControlState.normal)

        thatLabel.text = thisString

        thatButton.setTitle(thisString, for: UIControlState.normal)
    

    @IBAction func likePressed(_ sender: Any) 
        self.likeBtn.isEnabled = false
        let ref = FIRDatabase.database().reference()
        let keyToPost = ref.child("posts").childByAutoId().key

        ref.child("posts").child(self.postID).observeSingleEvent(of: .value, with:  (snapshot) in

            if let post = snapshot.value as? [String : AnyObject] 
                let updateLikes: [String : Any] = ["peopleWhoLike/\(keyToPost)" : FIRAuth.auth()!.currentUser!.uid]
                ref.child("posts").child(self.postID).updateChildValues(updateLikes, withCompletionBlock:  (error, reff) in

                    if error == nil 
                        ref.child("posts").child(self.postID).observeSingleEvent(of: .value, with:  (snap) in
                            if let properties = snap.value as? [String : AnyObject] 
                                if let likes = properties["peopleWhoLike"] as? [String : AnyObject] 
                                    let count = likes.count
                                    self.likeLabel.text = "\(count) Likes"

                                    let update = ["likes" : count]
                                    ref.child("posts").child(self.postID).updateChildValues(update)

                                    self.likeBtn.isHidden = true
                                    self.unlikeBtn.isHidden = false
                                    self.likeBtn.isEnabled = true
                                
                            
                        )
                    
                )
            


        )

        ref.removeAllObservers()
    


    @IBAction func unlikePressed(_ sender: Any) 
        self.unlikeBtn.isEnabled = false
        let ref = FIRDatabase.database().reference()


        ref.child("posts").child(self.postID).observeSingleEvent(of: .value, with:  (snapshot) in

            if let properties = snapshot.value as? [String : AnyObject] 
                if let peopleWhoLike = properties["peopleWhoLike"] as? [String : AnyObject] 
                    for (id,person) in peopleWhoLike 
                        if person as? String == FIRAuth.auth()!.currentUser!.uid 
                            ref.child("posts").child(self.postID).child("peopleWhoLike").child(id).removeValue(completionBlock:  (error, reff) in
                                if error == nil 
                                    ref.child("posts").child(self.postID).observeSingleEvent(of: .value, with:  (snap) in
                                        if let prop = snap.value as? [String : AnyObject] 
                                            if let likes = prop["peopleWhoLike"] as? [String : AnyObject] 
                                                let count = likes.count
                                                self.likeLabel.text = "\(count) Likes"
                                                ref.child("posts").child(self.postID).updateChildValues(["likes" : count])
                                            else 
                                                self.likeLabel.text = "0 Likes"
                                                ref.child("posts").child(self.postID).updateChildValues(["likes" : 0])
                                            
                                        
                                    )
                                
                            )

                            self.likeBtn.isHidden = false
                            self.unlikeBtn.isHidden = true
                            self.unlikeBtn.isEnabled = true
                            break

                        
                    
                
            

        )
        ref.removeAllObservers()
    

现在，我的视图控制器中的 'var postCell = segue.destination as！ PostCell'线。错误显示“执行错误”

任何和所有的帮助都会很棒。

【参考方案1】：

Segue.destination 返回 UIViewController 而不是 UICollectionViewCell

您应该在下一个视图控制器中创建一个变量并将文本分配给它，然后在那里显示它。

let vc = segue.destination as! NextViewController
vc.thisText = thisTextField.text!
vc.thatText = thatTextField.text!

然后在 NextViewController 中，您将拥有 thisText 和 thatText 中的输入

【讨论】：

我想要传递数据的标签和按钮都在单元格中，所以我无法在将数据传递给视图控制器时发送 segue 而不会出错

如果 cellForItemAt indexPath 不是这样，则将数据添加到单元格中

成功了吗？如果是的话，你能把它标记为一个好的答案吗？

它没有用

你能和我详细解释一下吗？