如何在 Swift 中使用 ViewWithTag？

Question

我是 Swift 的新手，但我之前在 Objective-C 工作过。如果单元格在 UITableView 中被重用，我在签入时遇到问题。

    let cell = tableView.dequeueReusableCellWithIdentifier(strCellId, forIndexPath:indexPath) as! MGSwipeTableCell
    cell.backgroundColor = UIColor.clearColor()

    let SMSObj = self.arraySMSContent[indexPath.row] as! SMSModel

    let lblMessage = UILabel(frame: CGRectMake(15, 10, Constants.SCREEN_WIDTH/1.4, Constants.SCREEN_HEIGHT/11))
    lblMessage.text = SMSObj.strSMSContent
    lblMessage.textAlignment = NSTextAlignment.Left
    lblMessage.numberOfLines = 2
    lblMessage.textColor = UIColor.whiteColor()
    cell.contentView.addSubview(lblMessage)

我用过MGSwipebleCell。滚动时 lblMessage 重叠。即使我们无法检查单元格是否为零。那么在这种情况下如何使用viewWithTag呢？特纳克斯

Answer 1

有很多方法可以解决您的问题。请尝试：

if let lblMessage = cell.contentView.viewWithTag(9999) as? UILabel { //Tag
    lblMessage.text = SMSObj.strSMSContent
}else{
    let lblMessage = UILabel(frame: CGRectMake(15, 10, Constants.SCREEN_WIDTH/1.4, Constants.SCREEN_HEIGHT/11))
    lblMessage.text = SMSObj.strSMSContent
    lblMessage.textAlignment = NSTextAlignment.Left
    lblMessage.numberOfLines = 2
    lblMessage.textColor = UIColor.whiteColor()
    lblMessage.tag = 9999 //Tag
    cell.contentView.addSubview(lblMessage)
}

Answer 2

除了使用 viewWithTag，您还可以使用单元格重用标识符注册自定义 class。然后您可以使用该子 class:

的属性访问标签

override func viewDidLoad() {
    super.viewDidLoad()

    tableView.registerClass(CustomCell.self, forCellReuseIdentifier: "CustomCell")
}

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("CustomCell", forIndexPath: indexPath) as! CustomCell

    cell.smsLabel.text = ...

    return cell
}

其中：

class CustomCell: MGSwipeTableCell {
    var smsLabel: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.textAlignment = .Left
        label.numberOfLines = 2
        label.textColor = .whiteColor()

        return label
    }()

    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)

        backgroundColor = .blueColor()

        contentView.addSubview(smsLabel)
        NSLayoutConstraint.activateConstraints([
            smsLabel.topAnchor.constraintEqualToAnchor(contentView.topAnchor, constant: 5),
            smsLabel.bottomAnchor.constraintEqualToAnchor(contentView.bottomAnchor, constant: -5),
            smsLabel.leadingAnchor.constraintEqualToAnchor(contentView.leadingAnchor, constant: 5),
            smsLabel.trailingAnchor.constraintEqualToAnchor(contentView.trailingAnchor, constant: -5)
        ])

        leftButtons = [MGSwipeButton(title: "Red", backgroundColor: .redColor())]
        leftSwipeSettings.transition = .Rotate3D;

        rightButtons = [MGSwipeButton(title: "Green", backgroundColor: .greenColor())]
        rightSwipeSettings.transition = .Rotate3D;
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        fatalError("not needed")
    }
}

如何在 Swift 中使用 ViewWithTag？

how to use ViewWithTag in Swift?

uitableview

viewwithtag

swift