加载tableView时解开可选值时意外发现nil

Question

I've been on stack for a while now but never needed to ask a question as I've always found the answers after some searching, but now I'm stuck for real. I've been searching around and going through some trial and error for an answer and I keeping getting the same error. I'm basically making a profile page with a tableView on the bottom half of the screen. The top half is loading fine filling in the current user's information. All connections to the view controller and cell view controller seem good. The table view, however, will appear with no data and crash while loading with the fatal error:

unexpectedly found nil while unwrapping an optional value.

I also believe the cellForRowAtIndexPath is not being called at all because "test" is not printing to the logs.

I'm using the latest versions of Swift and Parse.

I'm relatively new to swift so I'll go ahead and post my entire code here and any help at all is appreciated.

import UIKit
import Parse
import ParseUI

class profileViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {


@IBOutlet var tableView: UITableView!
@IBOutlet var profilePic: UIImageView!
@IBOutlet var userName: UILabel!
@IBOutlet var userBio: UILabel!
var image: PFFile!
var username = String()
var userbio = String()
var content = [String]()


@IBAction func logout(sender: AnyObject) {
    PFUser.logOut()
    let Login = storyboard?.instantiateViewControllerWithIdentifier("ViewController")
    self.presentViewController(Login!, animated: true, completion: nil)

}

override func viewDidLoad() {
    super.viewDidLoad()


    profilePic.layer.borderWidth = 1
    profilePic.layer.masksToBounds = false
    profilePic.layer.borderColor = UIColor.blackColor().CGColor
    profilePic.layer.cornerRadius = profilePic.frame.height/2
    profilePic.clipsToBounds = true


    tableView.delegate = self
    tableView.dataSource = self


    self.tableView.rowHeight = 80


    self.hideKeyboardWhenTappedAround()

    if let nameQuery = PFUser.currentUser()!["name"] as? String {
        username = nameQuery
    }

    if PFUser.currentUser()!["bio"] != nil {
    if let bioQuery = PFUser.currentUser()!["bio"] as? String {
        userbio = bioQuery
    }
    }

    if PFUser.currentUser()!["icon"] != nil {
    if let iconQuery = PFUser.currentUser()!["icon"] as? PFFile {
        image = iconQuery
    }
    }



    self.userName.text = username
    self.userBio.text = userbio

    if image != nil {
    self.image.getDataInBackgroundWithBlock { (data, error) -> Void in


        if let downIcon = UIImage(data: data!) {


            self.profilePic.image = downIcon

        }
        }

    }


    // Do any additional setup after loading the view.

    var postsQuery = PFQuery(className: "Posts")

    postsQuery.whereKey("username", equalTo: username)

    postsQuery.findObjectsInBackgroundWithBlock( { (posts, error) -> Void in

        if error == nil {

            if let objects = posts {
                self.content.removeAll(keepCapacity: true)

                for object in objects {
                    if object["postText"] != nil {
                        self.content.append(object["postText"] as! String)
                    }
                    self.tableView.reloadData()
                }
            }
        }

    })

}




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


func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    // #warning Potentially incomplete method implementation.
    // Return the number of sections.
    return 1
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // #warning Incomplete method implementation.
    // Return the number of rows in the section.
    print(content.count)
    return content.count
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let profCell = self.tableView.dequeueReusableCellWithIdentifier("profCell", forIndexPath: indexPath) as! profTableViewCell

    print("test")

    profCell.userPic.layer.borderWidth = 1
    profCell.userPic.layer.masksToBounds = false
    profCell.userPic.layer.borderColor = UIColor.blackColor().CGColor
    profCell.userPic.layer.cornerRadius = profCell.userPic.frame.height/2
    profCell.userPic.clipsToBounds = true


    profCell.userPic.image = self.profilePic.image
    profCell.name.text = self.username




    profCell.content.text = content[indexPath.row]



    return profCell
}

}

Answer 1

I let it sit for a few days and I came back to realize a very dumb mistake I made. I working with around 15 view controllers right now and realized I had a duplicate of the one I posted above with the same name. I now understand why you say working with storyboards is very sticky. Though, I did not need it, I appreciate the help and I can say I learned a few things.

Answer 2

You probably need to register the class you are using for the custom UITableViewCell:

self.tableView.registerClass(profTableViewCell.self, forCellReuseIdentifier: "profCell") 

Unless you're using prototyped cells in IB, this registration isn't done automatically for you.

As such when you call the dequeue method (with the ! forced unwrap) you're going to have issues. The dequeueReusableCellWithIdentifier:forIndexPath: asserts if you didn't register a class or nib for the identifier. when you register a class, this always returns a cell.

The older ( dequeueReusableCellWithIdentifier: ) version returns nil in that case, and you can then create your own cell.

You should use a ? during the as cast to avoid the crash, although you'll get no cells!

One other reminder, you should always use capitals for a class name, ProfTableViewCell not profTableViewCell , it's just good pratice.

Much more information here in the top answer by iOS genius Rob Mayoff: Assertion failure in dequeueReusableCellWithIdentifier:forIndexPath:

Answer 3

You have to create a simple NSObject Class with image, username and userbio as optional values. Then you have to declare in your profileviewcontroller a var like this:

var allProfiles = [yourNSObjectClass]()

In your cellForRowAtIndexPath add:

let profile = yourNSObjectClass()
profile = allProfiles[indexPath.row]

cell.username.text = profile.username

And go on.

Use also this:

   dispatch_async(dispatch_get_main_queue(), {
                self.tableView.reloadData()
            })

instead of this:

self.tableView.reloadData()