预期返回“ UITableViewCell”的函数中缺少返回

Question

EDIT 1: Revised code - still does not work.

I've got two custom cells.

The first cell (and only the first cell) will be of type CurrentIssueFrontCoverTableViewCell , and the rest of the cells will be of type CurrentIssueArticlesTableViewCell . I am getting the error, described in the title, when declaring my cellForRowAtIndexPath function. Any idea of to fix this ? Why is it not detecting that I'm returning the cell in my "if" loop ?

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

    let row = indexPath.row

    if indexPath.row == 0 {

        let cellWithCoverImage = tableView.dequeueReusableCellWithIdentifier(CurrentIssueFrontCoverTableCellIdentifier, forIndexPath: indexPath) as! CurrentIssueFrontCoverTableViewCell

        if let currentIssueFrontCoverObject = currentIssueObjects.objectAtIndex(indexPath.row) as? IssueElement {

            let title = currentIssueFrontCoverObject.title ?? ""

            let timeStampDateObject = NSDate(timeIntervalSince1970: NSTimeInterval(currentIssueFrontCoverObject.timeStamp))
            let timeStampDateString = dateFormatter.stringFromDate(timeStampDateObject)

            let issueNumber = currentIssueFrontCoverObject.issueNumber ?? ""
            let volumeNumber = currentIssueFrontCoverObject.volumeNumber ?? ""

            let nodeID = currentIssueFrontCoverObject.nodeID ?? 0

            let imageURL = currentIssueFrontCoverObject.imageURL ?? ""


            cellWithCoverImage.request?.cancel()

            if let coverImage = self.imageCache.objectForKey(imageURL) as? UIImage {
                cellWithCoverImage.currentIssueFrontCoverImageView.image = coverImage
            } else {
                cellWithCoverImage.currentIssueFrontCoverImageView.image = nil
                cellWithCoverImage.request = Alamofire.request(.GET, imageURL).responseImage() { response in
                    if let coverImage = response.result.value {
                        self.imageCache.setObject(response.result.value!, forKey: imageURL)
                        cellWithCoverImage.currentIssueFrontCoverImageView.image = coverImage

                    } else {

                    }
                }
            }
        } else {

        }

        return cellWithCoverImage

        // Populating data in the "Articles" type cells

} else if indexPath.row >= 1 {

        let cellWithoutCoverImage = tableView.dequeueReusableCellWithIdentifier(CurrentIssueArticlesTableCellIdentifier, forIndexPath: indexPath) as! CurrentIssueArticlesTableViewCell

        if let currentIssueArticleObject = currentIssueObjects.objectAtIndex(indexPath.row) as? IssueElement {

            let title = currentIssueArticleObject.title ?? ""

            let timeStampDateObject = NSDate(timeIntervalSince1970: NSTimeInterval(currentIssueArticleObject.timeStamp))
            let timeStampDateString = dateFormatter.stringFromDate(timeStampDateObject)

            let author = currentIssueArticleObject.author ?? ""

            let issueNumber = currentIssueArticleObject.issueNumber ?? ""
            let volumeNumber = currentIssueArticleObject.volumeNumber ?? ""

            let articleContent = currentIssueArticleObject.articleContent ?? ""

            let nodeID = currentIssueArticleObject.nodeID ?? 0


            cellWithoutCoverImage.currentIssueArticlesHeadlineLabel.font = UIFont.preferredFontForTextStyle(UIFontTextStyleHeadline)
            cellWithoutCoverImage.currentIssueArticlesHeadlineLabel.text = title

            cellWithoutCoverImage.currentIssueArticlesAuthorLabel.font = UIFont.preferredFontForTextStyle(UIFontTextStyleSubheadline)
            cellWithoutCoverImage.currentIssueArticlesAuthorLabel.text = author

            cellWithoutCoverImage.currentIssueArticlesPublishDateLabel.font = UIFont.preferredFontForTextStyle(UIFontTextStyleSubheadline)
            cellWithoutCoverImage.currentIssueArticlesPublishDateLabel.text = timeStampDateString

            return cellWithoutCoverImage

        } else {

        }
    }

    else {

    }
}

EDIT 1: Revised code - still does not work

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

    let row = indexPath.row

    switch(row) {


    case 0:

        let cellWithCoverImage = tableView.dequeueReusableCellWithIdentifier(CurrentIssueFrontCoverTableCellIdentifier, forIndexPath: indexPath) as! CurrentIssueFrontCoverTableViewCell

        if let currentIssueFrontCoverObject = currentIssueObjects.objectAtIndex(indexPath.row) as? IssueElement {

            let title = currentIssueFrontCoverObject.title ?? ""

            let timeStampDateObject = NSDate(timeIntervalSince1970: NSTimeInterval(currentIssueFrontCoverObject.timeStamp))
            let timeStampDateString = dateFormatter.stringFromDate(timeStampDateObject)

            let issueNumber = currentIssueFrontCoverObject.issueNumber ?? ""
            let volumeNumber = currentIssueFrontCoverObject.volumeNumber ?? ""

            let nodeID = currentIssueFrontCoverObject.nodeID ?? 0

            let imageURL = currentIssueFrontCoverObject.imageURL ?? ""


            cellWithCoverImage.request?.cancel()

            if let coverImage = self.imageCache.objectForKey(imageURL) as? UIImage {
                cellWithCoverImage.currentIssueFrontCoverImageView.image = coverImage
            } else {
                cellWithCoverImage.currentIssueFrontCoverImageView.image = nil
                cellWithCoverImage.request = Alamofire.request(.GET, imageURL).responseImage() { response in
                    if let coverImage = response.result.value {
                        self.imageCache.setObject(response.result.value!, forKey: imageURL)
                        cellWithCoverImage.currentIssueFrontCoverImageView.image = coverImage

                    } else {

                        return

                    }
                }
            }
        } else {

            break
        }

        return cellWithCoverImage;

        // Populating data in the "Articles" type cells



    default:

        let cellWithoutCoverImage = tableView.dequeueReusableCellWithIdentifier(CurrentIssueArticlesTableCellIdentifier, forIndexPath: indexPath) as! CurrentIssueArticlesTableViewCell

        if let currentIssueArticleObject = currentIssueObjects.objectAtIndex(indexPath.row) as? IssueElement {

            let title = currentIssueArticleObject.title ?? ""

            let timeStampDateObject = NSDate(timeIntervalSince1970: NSTimeInterval(currentIssueArticleObject.timeStamp))
            let timeStampDateString = dateFormatter.stringFromDate(timeStampDateObject)

            let author = currentIssueArticleObject.author ?? ""

            let issueNumber = currentIssueArticleObject.issueNumber ?? ""
            let volumeNumber = currentIssueArticleObject.volumeNumber ?? ""

            let articleContent = currentIssueArticleObject.articleContent ?? ""

            let nodeID = currentIssueArticleObject.nodeID ?? 0


            cellWithoutCoverImage.currentIssueArticlesHeadlineLabel.font = UIFont.preferredFontForTextStyle(UIFontTextStyleHeadline)
            cellWithoutCoverImage.currentIssueArticlesHeadlineLabel.text = title

            cellWithoutCoverImage.currentIssueArticlesAuthorLabel.font = UIFont.preferredFontForTextStyle(UIFontTextStyleSubheadline)
            cellWithoutCoverImage.currentIssueArticlesAuthorLabel.text = author

            cellWithoutCoverImage.currentIssueArticlesPublishDateLabel.font = UIFont.preferredFontForTextStyle(UIFontTextStyleSubheadline)
            cellWithoutCoverImage.currentIssueArticlesPublishDateLabel.text = timeStampDateString

            return cellWithoutCoverImage;

        } else {
            break
        }
    }

}

Answer 1

You need to remove the last else in your code cose it's empty. Also you could use a switch like:

switch(row){
    case 0:{
        // code with the CurrentIssueFrontCoverTableViewCell

        ....
        return cellWithCoverImage;
    }

    default:{

        // code with the CurrentIssueArticlesTableViewCell

        ...
        return cellWithoutCoverImage;
    }
}

Answer 2

The comment from Victor is correct. Because if you were to step through every possible outcome of the function, you could possibly reach the end of it without returning anything. You will need to provide a return statement for every possible outcome, including inside all of the 'else' blocks at the end that are currently empty.

Answer 3

Your problem is this:

} else {
    return
}

You can't have empty returns in a method expecting a return type, you need to return something here.

Every code path in your method must end in a return that returns a UITableViewCell. Anything that does not will make the compiler complain.