[英]How to call a function from an extension to UIViewController in Swift
[英]On long press, how do you call an ImagePreviewController: UIViewController from an objective c function instead of a contextMenuInteraction function?
下面這個 function 需要將 go 改為 ObjC function
///this 1st func is in UITableViewController, the others are in UITableViewCell
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as? ViewControllerTableViewCell {
...}
class ViewControllerTableViewCell: UITableViewCell, UIContextMenuInteractionDelegate
func contextMenuInteraction(_ interaction: UIContextMenuInteraction, configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
UIContextMenuConfiguration(identifier: nil, previewProvider: {
if self.cc == interaction {
let image3 = UIImage(named:"ringy.png")
if let unwrappedImage1 = image3 {
return ImagePreviewController(image:unwrappedImage1)
}
else {
return nil
}
}
else if self.vv == interaction{
let image3 = UIImage(named:"green.png")
if let unwrappedImage1 = image3 {
return ImagePreviewController(image:unwrappedImage1)
}
else {
return nil
}
}
else {
return nil
}
})
}
現在對象 C function
@objc func didLongPress() {
///database call
if ab as! Int>0 {
/// here the part for ringy.png needs to go
} else {
/////here the part for green.png needs to go
}
}
else {
print("No data available")
}
})
}
ObjC 在覆蓋 function 中獲取句柄
let longPress = UILongPressGestureRecognizer(target: self, action: #selector(didLongPress))
like?.addGestureRecognizer(longPress)
我目前遇到什么錯誤:
非空中空 function。 也就是說,如果我將代碼的 ringy/image3 和 green/image3 部分放入 objC function。
第一次回答后更新
我似乎可以使用答案和一些修改
weak var viewController: UIViewController?
viewController?.present(previewVC, animated: true, completion: nil)
cell.viewController = self ///inside cellForRowAt
我剩下的唯一問題是 ImagePreviewController 的尺寸錯誤/幾乎全屏。 他們應該是:
class ImagePreviewController: UIViewController {
private let imageView = UIImageView()
init(image: UIImage) {
super.init(nibName: nil, bundle: nil)
imageView.contentMode = .scaleAspectFill
imageView.clipsToBounds = true
imageView.image = image
view = imageView
let size = UIScreen.main.bounds.size
preferredContentSize = .init(width: size.width, height: size.height/1.55)
}
required init?(coder: NSCoder) {
super.init(coder: coder)
}
如果您想呈現一個新視圖 controller,您可以執行 segue(如果您使用故事板)或使用經典方式:
@objc func didLongPress() {
var image:UIImage?
// Some database call? How to get "ab"?
// Maybe you should not use as! in the following check:
if ab as! Int>0 {
image = UIImage(named:"ringy.png")
} else {
image = UIImage(named:"green.png")
}
if let image = image {
let previewVC = ImagePreviewController(image:image)
self.present(previewVC, animated: true, completion: nil)
} else {
print("No data available")
}
}
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