每次视图控制器启动时显示 UIAlertController
Show UIAlertController every time view controller launches
目前,UIAlertController 在用户点击 HeaderButton 时出现。我试图让 UIAlertController 在每次视图控制器最初启动时自动出现。有什么建议吗?
// MARK: - RestaurantListTableViewHeaderDelegate
extension RestaurantListViewController: RestaurantListTableViewHeaderDelegate {
func didTapHeaderButton(_ headerView: RestaurantListTableViewHeader) {
let locationPicker = UIAlertController(title: "Select location", message: nil, preferredStyle: .actionSheet)
for location in RestaurantListViewController.locations {
locationPicker.addAction(UIAlertAction(title: location, style: .default) { [weak self] action in
guard let `self` = self else { return }
self.currentLocation = action.title
self.tableView.reloadData()
})
}
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
locationPicker.addAction(cancelAction)
present(locationPicker, animated: true)
}
}
这不是一个优雅的解决方案,但它会起作用:
var alertAlreadyShown = false
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if !alertAlreadyShown {
alertAlreadyShown = true
/* Code for showing alert */
}
}
我保留了点击 Header Button 时的扩展名,并将以下内容添加到 viewDidLoad:
// Code for showing alert
let locationPicker = UIAlertController(title: "Select location", message: nil, preferredStyle: .actionSheet)
for location in RestaurantListViewController.locations {
locationPicker.addAction(UIAlertAction(title: location, style: .default) { [weak self] action in
guard let `self` = self else { return }
self.currentLocation = action.title
self.tableView.reloadData()
})
}
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
locationPicker.addAction(cancelAction)
present(locationPicker, animated: true)
目前,UIAlertController 在用户点击 HeaderButton 时出现。我试图让 UIAlertController 在每次视图控制器最初启动时自动出现。有什么建议吗?
// MARK: - RestaurantListTableViewHeaderDelegate
extension RestaurantListViewController: RestaurantListTableViewHeaderDelegate {
func didTapHeaderButton(_ headerView: RestaurantListTableViewHeader) {
let locationPicker = UIAlertController(title: "Select location", message: nil, preferredStyle: .actionSheet)
for location in RestaurantListViewController.locations {
locationPicker.addAction(UIAlertAction(title: location, style: .default) { [weak self] action in
guard let `self` = self else { return }
self.currentLocation = action.title
self.tableView.reloadData()
})
}
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
locationPicker.addAction(cancelAction)
present(locationPicker, animated: true)
}
}
这不是一个优雅的解决方案,但它会起作用:
var alertAlreadyShown = false
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if !alertAlreadyShown {
alertAlreadyShown = true
/* Code for showing alert */
}
}
我保留了点击 Header Button 时的扩展名,并将以下内容添加到 viewDidLoad:
// Code for showing alert
let locationPicker = UIAlertController(title: "Select location", message: nil, preferredStyle: .actionSheet)
for location in RestaurantListViewController.locations {
locationPicker.addAction(UIAlertAction(title: location, style: .default) { [weak self] action in
guard let `self` = self else { return }
self.currentLocation = action.title
self.tableView.reloadData()
})
}
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
locationPicker.addAction(cancelAction)
present(locationPicker, animated: true)