iOS Swift：当我滚动它时，Tableview数据消失了

Question

I have started Swift programming and little confuse about the tableview Control. For implementation i write following code, but the data goes disappear when i scroll it.

import UIKit

class ViewController: UIViewController {

    @IBOutlet  var tblView: UITableView

    var Array = ["1","2","3","4","5"]

    override func viewDidLoad() {
        super.viewDidLoad()

        tblView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {

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


    @IBAction func moveToNextView(sender: AnyObject) {

        var objNextViewController : NextViewController = NextViewController(nibName: "NextViewController", bundle: nil)
        self.navigationController.pushViewController(objNextViewController, animated: true)

    }

    func tableView(tableView: UITableView!, numberOfRowsInSection section: Int) -> Int {
        return Array.count
    }

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

        //var cell : UITableViewCell! = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "cell")

        var cell:UITableViewCell = tblView.dequeueReusableCellWithIdentifier("cell") as UITableViewCell
        var lblPrint : UILabel! = UILabel(frame: CGRectMake(10, 10, 100, 100))
        lblPrint.text = Array[indexPath.row]
        cell.contentView.addSubview(lblPrint)

        return cell
    }

}

what could be the right method to write for the above code?

Thanks

Answer 1

The problem is that you are adding var lblPrint : UILabel! each time when the cell appears.

Instead of adding custom label field, you can use UITableViewCell.textLabel .

For example:

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

    //var cell : UITableViewCell! = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "cell")

    var cell:UITableViewCell = tblView.dequeueReusableCellWithIdentifier("cell") as UITableViewCell
    cell.textLabel = Array[indexPath.row]
    return cell
}

Also you can try to create a custom cell with a custom label or you should check if the lblPrint already exists within contentView of cell.

Answer 2

For me this problem was fixed by overriding the following method. I just returned UITableViewAutomaticDimension from the method.

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

and set the following property for table view in TableViewController class.

tableView.estimatedRowHeight = 140