Question

我正试图通过执行瞄准来显示促销优惠券的详细信息，其中包含来自TableViewCel的信息到视图控制器中。

这是我在cellForRowAt indexPath方法中的代码，也是de Perform Segue功能：

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {


    let coupons = [couponImage1, couponImage2, couponImage3, couponImage4, couponImage5, couponImage6, couponImage7, couponImage8, couponImage9, couponImage10]
    let couponsTitle = [couponTitle1, couponTitle2, couponTitle3, couponTitle4, couponTitle5, couponTitle6, couponTitle7, couponTitle8, couponTitle9, couponTitle10]
    let couponsDescription = [couponDesc1, couponDesc2, couponDesc3, couponDesc4, couponDesc5, couponDesc6, couponDesc7, couponDesc8, couponDesc9, couponDesc10]
    let couponsCategory = [couponCat1, couponCat2, couponCat3, couponCat4, couponCat5, couponCat6, couponCat7, couponCat8, couponCat9, couponCat10]

    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! HomeTableViewCell

    cell.couponImg.image = coupons[indexPath.row]
    cell.couponTitle.text = couponsTitle[indexPath.row]
    cell.couponDescription.text = couponsDescription[indexPath.row]
    cell.couponCategory.text = couponsCategory[indexPath.row]

    if indexPath.row == 0 {
        self.sendCouponImg = couponImage1
        self.sendCouponTitle = couponTitle1
        self.sendCouponDesc = couponDesc1
        self.sendCouponCat = couponCat1
    } else if indexPath.row == 1 {
        self.sendCouponImg = couponImage2
        self.sendCouponTitle = couponTitle2
        self.sendCouponDesc = couponDesc2
        self.sendCouponCat = couponCat2
    } else if indexPath.row == 2 {
        self.sendCouponImg = couponImage3
        self.sendCouponTitle = couponTitle3
        self.sendCouponDesc = couponDesc3
        self.sendCouponCat = couponCat3
    } else if indexPath.row == 3 {
        self.sendCouponImg = couponImage4
        self.sendCouponTitle = couponTitle4
        self.sendCouponDesc = couponDesc4
        self.sendCouponCat = couponCat4
    } else if indexPath.row == 4 {
        self.sendCouponImg = couponImage5
        self.sendCouponTitle = couponTitle5
        self.sendCouponDesc = couponDesc5
        self.sendCouponCat = couponCat5
    } else if indexPath.row == 5 {
        self.sendCouponImg = couponImage6
        self.sendCouponTitle = couponTitle6
        self.sendCouponDesc = couponDesc6
        self.sendCouponCat = couponCat6
    } else if indexPath.row == 6 {
        self.sendCouponImg = couponImage7
        self.sendCouponTitle = couponTitle7
        self.sendCouponDesc = couponDesc7
        self.sendCouponCat = couponCat7
    } else if indexPath.row == 7 {
        self.sendCouponImg = couponImage8
        self.sendCouponTitle = couponTitle8
        self.sendCouponDesc = couponDesc8
        self.sendCouponCat = couponCat8
    } else if indexPath.row == 8 {
        self.sendCouponImg = couponImage9
        self.sendCouponTitle = couponTitle9
        self.sendCouponDesc = couponDesc9
        self.sendCouponCat = couponCat9
    } else if indexPath.row == 9 {
        self.sendCouponImg = couponImage10
        self.sendCouponTitle = couponTitle10
        self.sendCouponDesc = couponDesc10
        self.sendCouponCat = couponCat10
    }

    return cell

}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if(segue.identifier == "couponsDetails"){
        let viewController:DetailCouponsViewController = segue.destination as! DetailCouponsViewController
        viewController.getCouponsImage = self.sendCouponImg
        viewController.getCouponsTitle = self.sendCouponTitle
        viewController.getCouponsDescription = self.sendCouponDesc
        viewController.getCouponsCategory = self.sendCouponCat
    }
}

这是第二视图控制器的代码：

class DetailCouponsViewController: UIViewController {
 @IBOutlet weak var couponCategory: UILabel!
 @IBOutlet weak var couponTitle: UILabel!
 @IBOutlet weak var couponImage: UIImageView!
 @IBOutlet weak var couponDescription: UITextView!
 @IBOutlet weak var couponLongDescription: UITextView!
 @IBOutlet var starButtons: [UIButton]!


var getCouponsTitle : String = ""
var getCouponsDescription : String = ""
var getCouponsCategory : String = ""
var getCouponsImage : UIImage? = nil

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(false)
    self.couponCategory.text = getCouponsCategory
    self.couponDescription.text = getCouponsDescription
    self.couponLongDescription.text = getCouponsDescription
    self.couponTitle.text = getCouponsTitle
    self.couponImage.image = getCouponsImage
}

我的问题是详细视图控制器上出现的数据不正确，当我点击HomewTableViewCell上的第一行抛出第三行的值时，它们都混淆了。有谁能告诉我，我做错了什么？

Answer 1

cellForRowAt函数的目的是创建一个单元格对象，该对象是一个视图，配置它然后显示它们。向下滚动时，将调用此方法，以便准备然后显示下一个单元格。因此，如果您在此函数中设置变量，则这些变量中的值来自tableView准备显示的最后一个单元格。

例如，表视图有10行，其变量foo值从0到9.您的屏幕只能显示3个单元格。加载视图后，表视图将调用cellForRow三次以准备要显示的单元格0 1和2的视图。由于单元格2最后被处理，因此您的本地变量将具有值2.然后当您单击第一个单元格时，您将值2传递到下一个视图控制器。

为了使其正确，出于此功能的目的，首先需要将数组的定义移到外部，因为每次准备单元格时都不想重新创建。另外，单击单元格时还需要从其他函数访问数组。鉴于您的数组数据来自http请求，首先在外部创建变量为空数组。

var coupons: [String] = []
var couponsTitle: [String] = []
var couponsDescription: [String] = []
var couponsCategory: [String] = []

然后在您的HTTP回调中，向这些数组添加值，然后调用tableView.reloadData（）以使用来自服务器的数据重新加载表

func yourHTTPCallBack() {
    //coupons = [foo1, foo2 ...]
    tableView.reloadData()
}

在cellForRow中，您只显示单元格，而不是将任何值保存到局部变量。因为点击还没有发生！

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! HomeTableViewCell

    cell.couponImg.image = coupons[indexPath.row]
    cell.couponTitle.text = couponsTitle[indexPath.row]
    cell.couponDescription.text = couponsDescription[indexPath.row]
    cell.couponCategory.text = couponsCategory[indexPath.row]

    return cell
}

然后说你想在点击一个单元格时触发segue，从表格视图委托中使用这个功能

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    self.sendCouponImg = coupons[indexPath.row]
    self.sendCouponTitle = couponsTitle[indexPath.row]
    self.sendCouponDesc = couponsDescription[indexPath.row]
    self.sendCouponCat = couponsCategory[indexPath.row]

    //Do your segue here
}

通过Perform Segue将TableViewCell中的特定值发送到ViewController

1 个答案: