Segue 不向 ViewController 传递数据

Question

我正在尝试从 TableView 传递数据，因此当按下单元格时，该单元格上的数据将被传输到 viewController 并在那里显示，但我似乎无法让它工作。我试过这些帖子：

swift segue not passing data from tableview

Passing data from tableView to ViewController in Swift

Pass data through unwind segue

但要么我收到导致应用程序崩溃的错误，要么它不显示任何内容。我想做的是让用户对另一个用户发布的帖子发表评论，所以我试图从帖子中获取信息以详细显示它，但这就是我遇到麻烦的地方。这是我用来从表格视图传递数据的函数：

func objectAtIndexPath(indexPath: NSIndexPath) -> PFObject {
    return self.timelineData[indexPath.row] as! PFObject
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
    if(segue.identifier == "lookPosts"){
        let VC = segue.destinationViewController as! DetailViewContoller
        let indexPath: NSIndexPath! = self.tableView.indexPathForSelectedRow()
        VC.post = self.objectAtIndexPath(indexPath!) as PFObject
    }
}

这是 DetailViewController 的类：

import UIKit
import Parse

class DetailViewContoller: UIViewController, UITableViewDelegate, UITextViewDelegate {

    @IBOutlet weak var usernameLabel: UILabel!
    @IBOutlet weak var postTextView: UITextView!
    @IBOutlet weak var commentTableView: UITableView!

    var post: PFObject?
    var commentView: UITextView?
    var footerView: UIView?
    var contentHeight: CGFloat = 0

    var comments: [String]?
    let FOOTERHEIGHT : CGFloat = 50;

    override func viewDidLoad() {
        super.viewDidLoad()

        commentTableView.delegate = self

        /* Setup the keyboard notifications */
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyBoardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyBoardWillHide:", name: UIKeyboardWillHideNotification, object: nil)

        //gets the current user username
        usernameLabel.text = PFUser.currentUser()!.username as String?

        if(post?.objectForKey("comments") != nil) {
            comments = post?.objectForKey("comments") as? [String]
        }

        println(post)
        println(post?.objectForKey("content"))
        //self.postTextView.text = post?.objectForKey("content") as? String
    }

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

        self.postTextView.text = post?.objectForKey("content") as? String
        println(postTextView.text)
    }


    func keyBoardWillShow(notification: NSNotification) {
        var info:NSDictionary = notification.userInfo!
        var keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as! NSValue).CGRectValue()

        var keyboardHeight:CGFloat =  keyboardSize.height - 40


        var animationDuration:CGFloat = info[UIKeyboardAnimationDurationUserInfoKey] as! CGFloat

        var contentInsets: UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardHeight, 0.0);
        self.commentTableView.contentInset = contentInsets
        self.commentTableView.scrollIndicatorInsets = contentInsets

    }

    func keyBoardWillHide(notification: NSNotification) {

        self.commentTableView.contentInset = UIEdgeInsetsZero
        self.commentTableView.scrollIndicatorInsets = UIEdgeInsetsZero
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()

    }

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if let count = comments?.count {
            return count
        }
        return 0
    }

    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    }

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = commentTableView.dequeueReusableCellWithIdentifier("commentCell", forIndexPath: indexPath) as! CommentTableViewCell
        cell.commentLabel?.text = comments![indexPath.row]
        return cell
    }

    func tableView(tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
        if self.footerView != nil {
            return self.footerView!.bounds.height
        }
        return FOOTERHEIGHT
    }

    func tableView(tableView: UITableView, viewForFooterInSection section: Int) -> UIView? {
        footerView = UIView(frame: CGRect(x: 0, y: 0, width: commentTableView.bounds.width, height: FOOTERHEIGHT))
        footerView?.backgroundColor = UIColor(red: 243.0/255, green: 243.0/255, blue: 243.0/255, alpha: 1)
        commentView = UITextView(frame: CGRect(x: 10, y: 5, width: commentTableView.bounds.width - 80 , height: 40))
        commentView?.backgroundColor = UIColor.whiteColor()
        commentView?.textContainerInset = UIEdgeInsetsMake(5, 5, 5, 5)
        commentView?.layer.cornerRadius = 2
        commentView?.scrollsToTop = false

        footerView?.addSubview(commentView!)
        let button = UIButton(frame: CGRect(x: commentTableView.bounds.width - 65, y: 10, width: 60 , height: 30))
        button.setTitle("Reply", forState: UIControlState.Normal)
        button.backgroundColor = UIColor(red:  0/0.0, green: 179/255.0, blue: 204/255.0, alpha: 100.0/100.0)
        button.layer.cornerRadius = 5
        button.addTarget(self, action: "reply", forControlEvents: UIControlEvents.TouchUpInside)
        footerView?.addSubview(button)
        commentView?.delegate = self
        return footerView
    }


    //Hide keyboard after touching background
    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        self.view.endEditing(true)
    }

    //remaining characters
    func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool{

        if (text == "\n") {
            textView.resignFirstResponder()
        }

        return true
    }

    func reply() {
        post?.addObject(commentView!.text, forKey: "comments")
        post?.saveInBackground()
        if let tmpText = commentView?.text {
            comments?.append(tmpText)
        }
        commentView?.text = ""
        println(comments?.count)
        self.commentView?.resignFirstResponder()
        self.commentTableView.reloadData()
    }
}

所以我的问题是：还有其他传递数据的方法吗？或者我做错了什么数据没有通过？

Answer 1

这是实现这一目标的一种方法：

如果您的数据不大，那么您可以使用NSUserDefaults。

首先将数据存储到内存中：

NSUserDefaults.standardUserDefaults().setObject(yourObject, forKey: "yourKey")

在另一个 viewController 中从内存中读取数据：

let yourObject = NSUserDefaults.standardUserDefaults().objectForKey("yourKey") as! PFObject

希望对你有帮助。