Question

在OrderFormViewController我有tableView而tableViewCell我有一个cameraButton，在点按时会显示提醒。

现在当OrderFormViewController出现（未推送）时，它会加载tableView并且它的单元格（行数是1硬编码的）。< / p>

我在IBAction的{{1}}下面有以下代码：

cameraButton

我搜索了这个，所以这就是为什么我尝试@IBAction func cameraButtonPressed(_ sender: Any) { //DispatchQueue.main.async { let alert = UIAlertController(title: "Choose Image From", message: nil, preferredStyle: .alert) alert.addAction(UIAlertAction(title: "Camera", style: .default, handler: { _ in if(UIImagePickerController .isSourceTypeAvailable(UIImagePickerControllerSourceType.camera)) { self.imagePicker.sourceType = UIImagePickerControllerSourceType.camera self.imagePicker.allowsEditing = true UIApplication.shared.keyWindow?.rootViewController?.present(self.imagePicker, animated: true, completion: nil) } else { let alert = UIAlertController(title: "Warning", message: "You don't have camera", preferredStyle: .alert) alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil)) UIApplication.shared.keyWindow?.rootViewController?.present(alert, animated: true, completion: nil) } })) alert.addAction(UIAlertAction(title: "Gallery", style: .default, handler: { _ in self.imagePicker.sourceType = UIImagePickerControllerSourceType.photoLibrary self.imagePicker.allowsEditing = false UIApplication.shared.keyWindow?.rootViewController?.present(self.imagePicker, animated: true, completion: nil) })) //alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil)) alert.addAction(UIAlertAction.init(title: "Cancel", style: .cancel, handler: nil)) UIApplication.shared.keyWindow?.rootViewController?.present(alert, animated: true, completion: nil) //} }并尝试从UIApplication.shared.keyWindow?.rootViewController运行它，但有些DispatchQueue.main.async无效。

更新如果我按下视图控制器，那么它可以工作。但我需要一个解决方案来呈现视图控制器。

Answer 1

我强烈建议重构整个解决方案以使用代理人 - 委托从UITableViewCell向OrderFormViewController提交提醒的操作，只需使用

self.present(alert, animated: true, completion: nil)

因为使用UIApplication.shared.keyWindow?.rootViewController非常脆弱。

所以只是为你勾勒出来，我相信最好的方法就是：

class OrderFormViewController: UITableViewController {

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "customCell", for: indexPath) as! CustomCell
        // set the delegate
        cell.delegate = self
        return cell
    }
}

extension OrderFormViewController: CustomCellDelegate {
    func customCellDelegateButtonPressed(_ customCell: CustomCell) {

        let alert = UIAlertController(title: "Choose Image From", message: nil, preferredStyle: .alert)
        // configure the alert

        // now the presentation of the alert is delegated here to OrderFormViewController, so it can simply use self to present
        self.present(alert, animated: true, completion: nil)
    }
}

protocol CustomCellDelegate: class {
    func customCellDelegateButtonPressed(_ customCell: CustomCell /*, potentially more parameters if needed */)
}

class CustomCell: UITableViewCell {
    // rest omitted for brevity

    weak var delegate: CustomCellDelegate?

    @IBAction func cameraButtonPressed(_ sender: Any) {
        delegate?.customCellDelegateButtonPressed(self)
    }
}

TableViewCell未显示alertView

1 个答案: