CODEWITHSUNDEEP
iosswiftsegue
user3708224
user3708224

Reputation: 1259

prepareForSegue crashes app

So my segue is crashing here and I am not sure why...There are no errors shown but when I run the app in the simulator and then hit the button to segue it crashes with this error in the debugger: Could not cast value of type 'DNApp.StoriesTableViewController' (0x1077d5a80) to 'UITableViewCell' (0x109d8ca18). (lldb)

Below is the relevant code:

class StoriesTableViewController: UITableViewController, StoryTableViewCellDelegate {


override func viewDidLoad() {
    super.viewDidLoad()


    tableView.estimatedRowHeight = 100
    tableView.rowHeight = UITableViewAutomaticDimension
}


override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return data.count

}

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    let cell = tableView.dequeueReusableCellWithIdentifier("StoryCell") as! StoryTableViewCell

    let story = data[indexPath.row]
    cell.configureWithStory(story)
    cell.delegate = self
    return cell   
}

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    performSegueWithIdentifier("WebSegue", sender: self)
    tableView.deselectRowAtIndexPath(indexPath, animated: true)
}

// MARK: StoryTableViewCellDelegate

func storyTableViewCellDidTouchUpvote(cell: StoryTableViewCell, sender: AnyObject) {
    // TODO: Implement Upvote
}

func storyTableViewCellDidTouchComment(cell: StoryTableViewCell, sender: AnyObject) {
    performSegueWithIdentifier("CommentsSegue", sender: self)
}

//MARK: Misc
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "CommentsSegue" {
        let toView = segue.destinationViewController as! CommentsTableViewController
        let indexPath = tableView.indexPathForCell(sender as! UITableViewCell)!
        toView.story = data[indexPath.row]
    }
}

}

Upvotes: 1

Views: 905

Answers (3)

Icaro
Icaro

Reputation: 14845

That is because your cell is not a UITableViewCell but a StoryTableViewCell. If you use if let instead instead the forced wrapping you are seeing your app will not crash, however you won't be able to access the values in the cell, you just need to cast your cell correctly as below:

class StoriesTableViewController: UITableViewController, StoryTableViewCellDelegate {

var myIndexPat = NSIndexPath()

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    myIndexPath = indexPath
    performSegueWithIdentifier("WebSegue", sender: self)
    tableView.deselectRowAtIndexPath(indexPath, animated: true)
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "CommentsSegue" {
        let toView = segue.destinationViewController as! CommentsTableViewController
        let indexPath = tableView.indexPathForCell(myIndexPath) as! StoryTableViewCell
        toView.story = data[indexPath.row]
    }
}

Upvotes: 1

NSDeveloper
NSDeveloper

Reputation: 1640

func storyTableViewCellDidTouchComment(cell: StoryTableViewCell, sender: AnyObject) {
    performSegueWithIdentifier("CommentsSegue", sender: self)
}

In prepareForSegue method sender is kind of StoriesTableViewController class,force cast to UITableViewCell lead to crash.

Upvotes: 0

Patrick Lynch
Patrick Lynch

Reputation: 2782

Sorry, I misread your question entirely! Your crash is still due to force unwrapping. You should use optional bindings (if let) instead. You can do multiple bindings at once and use a where clause to make the code a little cleaner, too:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if let toView = segue.destinationViewController as? CommentsTableViewController where segue.identifier == "CommentsSegue" {
        if let cell = sender as? UITableViewCell,
            let indexPath = tableView.indexPathForCell( cell ) {
            toView.story = data[indexPath.row]
        }
    }
}

Upvotes: 1

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