使用 Swift 和 Firebase 中的协议从 UITableview 传递数据

Question

I have a tableview called PostsTableView that has a list of user posts with a UIButton called "Comment". When a user clicks Comment, I would like it to redirect to CommentViewController that has all the information around the post such as the postText and the user who wrote the post.

Snippets of the code below.

PostsTableView

extension PostsTableViewController: PostsTableViewCellDelegate {

  func commentTapped(postInfo: String) {

  //How do I pass postInfo along to CommentViewController

  }

PostsTableViewCell

protocol TableViewCellDelegate {

  func commentTapped(postInfo: String)

}

class PostsTableViewCell: UITableViewCell {

@IBOutlet weak var postTextLabel: UILabel!
@IBOutlet weak var postUserLabel: UILabel!

var postItem: Post!
var delegate: TableViewCellDelegate?

override func awakeFromNib() {
    super.awakeFromNib()
    // Initialization code
}

@IBAction func commentAction(_ sender: Any) {

delegate?.commentTapped(postInfo: postItem.postText)

}
}

Answer 1

Assuming you are using segues, you will call .performSegue(withIdentifier: "mySegueIdentifier", sender: self)

You could store the postInfo first by adding a variable to PostsTableViewController

var selectedPostInfo: String?

And then setting it in commentTapped(postInfo: String)

func commentTapped(postInfo: String) {
    selectedPostInfo = postInfo

    performSegue(withIdentifier: "mySegueIdentifier")
}

Now override controller.prepare(for: UIStoryboardSegue, sender: Any?) and set the value on CommentViewController :

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let controller = segue.destination as? CommentViewController {
        controller.postInfo = selectedPostInfo
    }
}

Answer 2

You can do something like this

1) Firstof all refactor the delegate method to take post object as an argument instead of just a String (This helps to provide better User Experience since no need to fetch data already available locally at that moment). Something like this

func commentTapped(postObject: Post) { // I am assuming your Post model has got all the info required by the CommentsViewController
  }

2) Now create a property in CommentsViewController let's say post, which you can I initialise as below code

func commentTapped(postObject: Post) {
 let commentVC = CommentsViewController.initWithNib... // Initialise the Comments ViewController
 commentVC.post = postObject // Assign the post object here
 show(commentVC) // Present here the commentVC as per your requirement of Modal or Push
}