MainViewController
class MainViewController: UIViewController {
@IBOutlet weak var imagePreview: UIImageView!
@IBOutlet weak var buttonClear: UIButton!
@IBOutlet weak var buttonSave: UIButton!
@IBOutlet weak var itemAdd: UIBarButtonItem!
private let bag = DisposeBag()
private let images = BehaviorRelay<[UIImage]>(value: [])
override func viewDidLoad() {
super.viewDidLoad()
images.subscribe(onNext: { [weak imagePreview] photos in
guard let preview = imagePreview else { return }
preview.image = photos.collage(size: preview.frame.size)
})
.disposed(by: bag)
}
@IBAction func actionClear() {
images.accept([])
}
@IBAction func actionSave() {
}
@IBAction func actionAdd() {
let newImages = images.value + [UIImage(named: "IMG_1907.jpg")!]
images.accept(newImages)
}
func showMessage(_ title: String, description: String? = nil) {
let alert = UIAlertController(title: title, message: description, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Close", style: .default, handler: { [weak self] _ in self?.dismiss(animated: true, completion: nil)}))
present(alert, animated: true, completion: nil)
}
}
override func viewDidLoad() {
super.viewDidLoad()
// ------- 中略 -------
images.subscribe(onNext: { [weak self] photos in
self?.updateUI(photos: photos)
})
.disposed(by: bag)
}
private func updateUI(photos: [UIImage]) {
buttonSave.isEnabled = photos.count > 0 && photos.count % 2 == 0
buttonClear.isEnabled = photos.count > 0
itemAdd.isEnabled = photos.count < 6
title = photos.count > 0 ? "\(photos.count) photos" : "Collage"
}
MainViewController
@IBAction func actionAdd() {
let photosViewController = storyboard!.instantiateViewController(withIdentifier: "PhotosViewController") as! PhotosViewController
navigationController!.pushViewController(photosViewController, animated: true)
photosViewController.selectedPhotos
.subscribe(
onNext: { [weak self] newImage in
guard let images = self?.images else { return }
images.accept(images.value + [newImage])
},
onDisposed: {
print("Completed photo selection")
}
)
.disposed(by: bag)
}PhotosViewController
/*
You'd like to add a PublishSubject to expose the selected photos,
but you don't want the subject publicly accessible, as that would allow other classes to call onNext(_) and make the subject emit values.
*/
private let selectedPhotosSubject = PublishSubject<UIImage>()
var selectedPhotos: Observable<UIImage> {
return selectedPhotosSubject.asObservable()
}
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let asset = photos.object(at: indexPath.item)
if let cell = collectionView.cellForItem(at: indexPath) as? PhotoCell {
cell.flash()
}
imageManager.requestImage(for: asset, targetSize: view.frame.size, contentMode: .aspectFill, options: nil, resultHandler: { [weak self] image, info in
guard let image = image, let info = info else { return }
if let isThumnail = info[PHImageResultIsDegradedKey as NSString] as? Bool, !isThumnail {
self?.selectedPhotosSubject.onNext(image)
}
})
}PhotosViewController
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
selectedPhotosSubject.onCompleted()
}