我有一个警报视图，试图在照片视图上呈现。
照片显示在列表中，并且可以推送到全屏视图。
照片视图正在以编程方式显示。我认为这就是导致问题的原因，因为警报视图试图在已经呈现的（照片）视图之上呈现另一个视图。
警报视图正在尝试显示，但出现此错误：
Warning: Attempt to present <UIAlertController: 0x147d2c6b0> on <LiveDeadApp.ListViewController: 0x147d614c0> which is already presenting (null)
可能有问题的行是这一行：
self.present(textPrompt, animated: true, completion: nil)
This is the main list view
This is the main list view when a screenshot is taken
This is the main photo view
This is the popover in the main photo view (accessed via the "i" button)
When a screenshot is taken on the main photo view, no alert view occurs. However, when the device's orientation is changed, the photo view goes back to the list and shows the alert.
This is what I am trying to do:
iOS 10 中的 Swift 3
谢谢你！
这是列表视图和照片视图的代码：
import UIKit
import Kingfisher
import SKPhotoBrowser
class ListViewCell: UITableViewCell {
@IBOutlet weak var Cellimage: UIImageView!
@IBOutlet weak var cellVenue: UILabel!
@IBOutlet weak var cellLocation: UILabel!
@IBOutlet weak var cellDate: UILabel!
@IBOutlet weak var aiView: UIActivityIndicatorView!
}
class ListViewController: UITableViewController {
var subcategory:Subcategory!
var objects:[[String:String]] = [[String:String]]()
var images = [SKPhotoProtocol]()
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
}
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.separatorStyle = .none
self.view.backgroundColor = UIColor.black
self.navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
navigationController!.navigationBar.barTintColor = UIColor.black
let requireTextInput = "require text input"
// add observer for screen shot
NotificationCenter.default.addObserver(forName: NSNotification.Name.UIApplicationUserDidTakeScreenshot, object: nil, queue: OperationQueue.main, using:
{ notification in
self.definesPresentationContext = true
var inputTextField = UITextField()
let textPrompt = UIAlertController(title: "Test!", message: "Testing!", preferredStyle: .alert)
textPrompt.addAction(UIAlertAction(title: "Continue", style: .default, handler: {
(action) -> Void in
// if the input match the required text
let str = inputTextField.text
if str == requireTextInput {
print("right")
} else {
print("wrong")
}
}))
textPrompt.addTextField(configurationHandler: {(textField: UITextField!) in
textField.placeholder = ""
inputTextField = textField
})
self.present(textPrompt, animated: true, completion: nil)
})
if subcategory != nil {
self.title = subcategory.title
self.objects = subcategory.photos
createLocalPhotos()
self.tableView.reloadData()
}
}
func createLocalPhotos() {
for item in objects {
let photo = SKPhoto.photoWithImageURL(item["url"]!)
photo.shouldCachePhotoURLImage = true
images.append(photo)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return objects.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell: ListViewCell = tableView.dequeueReusableCell(withIdentifier: "Cell") as! ListViewCell
let item = objects[indexPath.row]
let title = item["title"]
let location = item["location"]
let date = item["date"]
let urlSrt = item["url"]
cell.cellVenue.text = title
cell.cellLocation.text = location
cell.cellDate.text = date
if let url = URL(string: urlSrt!) {
cell.aiView.startAnimating()
cell.Cellimage.kf.setImage(with: url, placeholder: nil, options: nil, progressBlock: nil, completionHandler: { (image, error, cacheType, url) in
cell.aiView.stopAnimating()
})
}
return cell
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let cell = tableView.cellForRow(at: indexPath) as! ListViewCell
if(cell.Cellimage.image != nil ) {
SKPhotoBrowserOptions.displayToolbar = false
SKPhotoBrowserOptions.displayCounterLabel = false
SKPhotoBrowserOptions.displayBackAndForwardButton = false
SKPhotoBrowserOptions.displayAction = false
SKPhotoBrowserOptions.displayDeleteButton = true
SKPhotoBrowserOptions.displayHorizontalScrollIndicator = false
SKPhotoBrowserOptions.displayVerticalScrollIndicator = false
SKPhotoBrowserOptions.displayStatusbar = false
SKPhotoBrowserOptions.disableVerticalSwipe = true
SKPhotoBrowserOptions.bounceAnimation = false
let browser = ExtendedSKPhotoBrowser(originImage: cell.Cellimage.image!, photos: images, animatedFromView: cell)
let btnSize = 80//24 * UIScreen.main.scale
browser.updateCloseButton(UIImage(named: "ic_close_white")!, size: CGSize(width: btnSize, height: btnSize))
browser.updateDeleteButton(UIImage(named: "ic_info_white")!, size: CGSize(width: btnSize, height: btnSize))
browser.initializePageIndex(indexPath.row)
browser.delegate = self
present(browser, animated: true, completion: {})
browser.toggleControls()
}
}
override var prefersStatusBarHidden: Bool {
get {
return true
}
}
var popOverVC:PopUpViewController!
}
extension ListViewController: SKPhotoBrowserDelegate {
func didShowPhotoAtIndex(_ index: Int) {
}
func willDismissAtPageIndex(_ index: Int) {
}
private func willShowActionSheet(photoIndex: Int) {
// do some handle if you need
}
func didDismissAtPageIndex(_ index: Int) {
}
func didDismissActionSheetWithButtonIndex(_ buttonIndex: Int, photoIndex: Int) {
// handle dismissing custom actions
}
func removePhoto(_ browser: SKPhotoBrowser, index: Int, reload: (() -> Void)) {
popOverVC = self.storyboard?.instantiateViewController(withIdentifier: "sbPopUpID") as! PopUpViewController
popOverVC.photoData = objects[index]
}
func viewForPhoto(_ browser: SKPhotoBrowser, index: Int) -> UIView? {
return tableView.cellForRow(at: IndexPath(row: index, section: 0))
}
}
open class ExtendedSKPhotoBrowser: SKPhotoBrowser {
open override var preferredStatusBarStyle: UIStatusBarStyle {
return .lightContent // white statusbar, .default is black
}
open override var prefersStatusBarHidden: Bool {
return true
}
}
嘿，我尝试了一个更简单的解决方案，该解决方案似乎有效，并且能够在第一个警报之前显示第二个警报，该警报将保留（在用户回答问题之前无需关闭）：
if self.presentedViewController==nil{
self.present(MyAlert, animated: true, completion: nil)
}else{
self.presentedViewController!.present(MyAlert, animated: true, completion: nil)
}