Swift-滚动时出现tableViewCell问题

Question

I'm creating a chat app using swift. On my storyboard, I have one View Controller that is responsible for showing the messages. I have 3 swift files :

• ChatingViewController : Class associated with the View Controller on the storyboard

• CustomChatingTableViewController

• CellChatingTableViewCell

Each message is displayed in a cell. I create the tableView programmatically.

- ChatingViewController

            import UIKit

            class ChatingViewController: UIViewController {

            var messageController = [[String:String]]()

            var tableViewController = CustomChatingTableViewController()

            override func viewDidLoad() {

                let sizeTableView = CGSize(width: view.frame.size.width - 2 * margin, height: view.frame.size.height - sizeTextField.height - 2 * margin - self.navigationController!.navigationBar.frame.size.height)
                let originTableView = CGPoint(x: margin, y: 2 * margin + self.navigationController!.navigationBar.frame.size.height)

                tableViewController.tableView.frame = CGRect(origin: originTableView, size: sizeTableView)
                tableViewController.tableView.registerClass(CellChatingTableViewCell.self, forCellReuseIdentifier: "Cell")
                tableViewController.data = messageController
                tableViewController.tableView.separatorStyle = .None

                view.addSubview(tableViewController.tableView)
    }

- CustomChatingTableViewController

import UIKit

class CustomChatingTableViewController: UITableViewController {


    var data:[[String:String]]!

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return data.count
    }


    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        var cell = tableView.dequeueReusableCellWithIdentifier("Cell") as CellChatingTableViewCell

        cell.setCell(data[indexPath.row]["name"] as String!, date: data[indexPath.row]["date"] as String!, message: data[indexPath.row]["message"] as String!)

        return cell


    }

    override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
        return 150
    }

}

** -CellChatingTableViewCell**

import UIKit
class CellChatingTableViewCell: UITableViewCell {

    var date =  UILabel()
    var message = UILabel()

func setCell(name:String,date:String,message:String){


    let imageContainerMessage = UIImage(named: "orange.png")!.stretchableImageWithLeftCapWidth(24, topCapHeight: 15)


    self.date.font = UIFont(name: "Arial", size: 10)
    self.date.text = date
    self.date.numberOfLines = 0
    self.date.lineBreakMode = NSLineBreakMode.ByWordWrapping
    let sizeDateLabelMax = CGSizeMake(self.frame.size.width, 9999)
    let expectedSizeDate = self.date.sizeThatFits(sizeDateLabelMax)
    self.date.frame = CGRect(origin: CGPoint.zeroPoint, size: expectedSizeDate)



    self.message.font = UIFont(name: "Arial", size: 15)
    self.message.text = message
    self.message.numberOfLines = 0
    self.message.lineBreakMode = NSLineBreakMode.ByWordWrapping
    let sizeMessageLabelMax = CGSizeMake(self.frame.size.width, 9999)
    let expectedSizeMessage = self.message.sizeThatFits(sizeMessageLabelMax)
    self.message.frame = CGRect(origin: CGPoint(x: 15, y: 10), size: expectedSizeMessage)

    var imageContainer = UIImageView(frame: CGRect(origin: CGPoint(x: 0, y: expectedSizeDate.height + 5), size:
        CGSizeMake(expectedSizeMessage.width + 25, expectedSizeMessage.height +  25)))
    imageContainer.image = imageContainerMessage


    self.addSubview(self.date)
    self.addSubview(imageContainer)
    imageContainer.addSubview(self.message)
}
}

When I load the ViewController, everything does work fine but when I scroll the tableView, it turns horrible:

Before scrolling :

After scrolling :

Any suggestion?

Thanks in advance

Answer 1

In your cellForRowAtIndexPath , you are reusing cells. But then in your custom UITableViewCell , you are adding ( self.addSubView ) self.date and self.message multiple times (yikes), and adding new instances of imageContainer .

You should either clear the cells before re-adding them, or invalidate them with new data but do not do self.addSubView again.