MLMediaLibrary - отображение библиотеки фотографий - неверный код смены кода - macOS
Попытка показать фотографии из библиотеки фотографий. Пример кода Apple, приведенный ниже, не работает должным образом. Он не ждет уведомлений, но пытается запустить представление коллекции, которое выдает сбой при Количество элементов в разделе, потому что нет данных для отображения.
Спасибо за любую помощь от вас, гуру Свифта там!
/*
Copyright (C) 2016 Apple Inc. All Rights Reserved.
See LICENSE.txt for this sample’s licensing information
Abstract:
The `ViewController` class is a subclass to NSViewController responsible for managing the app's content.
*/
import Cocoa
import MediaLibrary
class IconViewBox : NSBox {
override func hitTest(_ aPoint: NSPoint) -> NSView? {
// Don't allow any mouse clicks for subviews in this NSBox.
return nil
}
}
// MARK: -
class ViewController: NSViewController, NSCollectionViewDelegate {
// MARK: - Types
// Keys describing the dictionary for each photo loaded.
private struct ItemKeys {
static let imageKey = "icon"
static let nameKey = "name"
}
// MLMediaLibrary property values for KVO.
private struct MLMediaLibraryPropertyKeys {
static let mediaSourcesKey = "mediaSources"
static let rootMediaGroupKey = "rootMediaGroup"
static let mediaObjectsKey = "mediaObjects"
static let contentTypeKey = "contentType"
}
// MARK: - Properties
/**
The KVO contexts for `MLMediaLibrary`.
This provides a stable address to use as the `context` parameter for KVO observation methods.
*/
private var mediaSourcesContext = 1
private var rootMediaGroupContext = 2
private var mediaObjectsContext = 3
private var photoSize = CGSize(width: 168, height: 145)
// Contains an array of dictionaries describing each photo (refer to ItemKeys for key/values).
@IBOutlet weak var arrayController: NSArrayController!
@IBOutlet weak var collectionView: NSCollectionView!
@IBOutlet private weak var noPhotosLabel: NSTextField!
@IBOutlet private weak var activityIndicator: NSProgressIndicator!
// MLMediaLibrary instances for loading the photos.
private var mediaLibrary: MLMediaLibrary!
private var mediaSource: MLMediaSource!
private var rootMediaGroup: MLMediaGroup!
// MARK: - View Controller Lifecycle
override func viewDidLoad() {
super.viewDidLoad()
print ("VDL1...................")
// Start progress indicator in case fetching the photos from the photo library takes time.
self.activityIndicator.isHidden = false
self.activityIndicator.startAnimation(self)
self.collectionView.minItemSize = self.photoSize
self.collectionView.maxItemSize = self.photoSize
self.arrayController.setSelectionIndex(-1) // No selection to start out with.
// Setup the media library to load only photos, don't include other source types.
let options: [String : AnyObject] =
[MLMediaLoadSourceTypesKey: MLMediaSourceType.image.rawValue as AnyObject,
MLMediaLoadIncludeSourcesKey: [MLMediaSourcePhotosIdentifier, MLMediaSourceiPhotoIdentifier] as AnyObject]
// Create our media library instance to get our photo.
mediaLibrary = MLMediaLibrary(options: options)
// We want to be called when media sources come in that's available (via observeValueForKeyPath).
self.mediaLibrary.addObserver(self,
forKeyPath: MLMediaLibraryPropertyKeys.mediaSourcesKey,
options: NSKeyValueObservingOptions.new,
context: &mediaSourcesContext)
if (self.mediaLibrary.mediaSources != nil) {
print ("VDL2...................")
} // Reference returns nil but starts the asynchronous loading.
}
deinit {
// Make sure to remove us as an observer before "mediaLibrary" is released.
self.mediaLibrary.removeObserver(self, forKeyPath: MLMediaLibraryPropertyKeys.mediaSourcesKey, context:&mediaSourcesContext)
}
// MARK: - NSCollectionViewDataSource
func numberOfSectionsInCollectionView(_ collectionView: NSCollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
let photos = self.arrayController.arrangedObjects as! NSArray
return photos.count
}
func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAtIndexPath indexPath: IndexPath) -> NSCollectionViewItem {
let item = collectionView.makeItem(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "IconItem"), for:indexPath)
let photos = self.arrayController.arrangedObjects as! NSArray
let iconInfo = photos[(indexPath as NSIndexPath).item]
item.representedObject = iconInfo
return item
}
// MARK: - NSCollectionViewDelegate
func collectionView(_ collectionView: NSCollectionView, didSelectItemsAt indexPaths: Set<IndexPath>) {
if let itemIndexPath = indexPaths.first {
let photos = self.arrayController.arrangedObjects as! NSArray
let itemDict = photos[((itemIndexPath as NSIndexPath).item)] as! NSDictionary
if let itemTitle = itemDict[ItemKeys.nameKey] as? String {
if (itemTitle.characters.count > 0) {
print("selected photo: '\(itemTitle)'")
}
else {
print("selected photo: <no title>")
}
}
}
}
// MARK: - Utilities
/// Helps to make sure the media object is the photo format we want.
private func isValidImage(_ mediaObject: MLMediaObject) -> Bool {
var isValidImage = false
let attrs = mediaObject.attributes
let contentTypeStr = attrs[MLMediaLibraryPropertyKeys.contentTypeKey] as! String
// We only want photos, not movies or older PICT formats (PICT image files are not supported in a sandboxed environment).
if ((contentTypeStr != kUTTypePICT as String) && (contentTypeStr != kUTTypeQuickTimeMovie as String))
{
isValidImage = true
}
return isValidImage
}
/// Obtains the title of the MLMediaObject (either the meta name or the last component of the URL).
func imageTitle(_ fromMediaObject: MLMediaObject) -> String {
guard let title = fromMediaObject.attributes["name"] else {
return fromMediaObject.url!.lastPathComponent
}
return title as! String
}
// MARK: - Photo Loading
/// Observer for all key paths returned from the MLMediaLibrary.
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
print ("Observe1...................")
if (keyPath == MLMediaLibraryPropertyKeys.mediaSourcesKey && context == &mediaSourcesContext && object! is MLMediaLibrary) {
// The media sources have loaded, we can access the its root media.
if let mediaSource = self.mediaLibrary.mediaSources?[MLMediaSourcePhotosIdentifier] {
self.mediaSource = mediaSource
}
else if let mediaSource = self.mediaLibrary.mediaSources?[MLMediaSourceiPhotoIdentifier] {
self.mediaSource = mediaSource
}
else {
print ("Observe2...................")
// Can't find any media sources.
self.noPhotosLabel.isHidden = false
// Stop progress indicator.
self.activityIndicator.isHidden = true
self.activityIndicator.stopAnimation(self)
return // No photos found.
}
// Media Library is loaded now, we can access mediaSource for photos
self.mediaSource.addObserver(self,
forKeyPath: MLMediaLibraryPropertyKeys.rootMediaGroupKey,
options: NSKeyValueObservingOptions.new,
context: &rootMediaGroupContext)
// Obtain the media grouping (reference returns nil but starts asynchronous loading).
if (self.mediaSource.rootMediaGroup != nil) {}
}
else if (keyPath == MLMediaLibraryPropertyKeys.rootMediaGroupKey && context == &rootMediaGroupContext && object! is MLMediaSource) {
print ("Observe3...................")
// The root media group is loaded, we can access the media objects.
// Done observing for media groups.
self.mediaSource.removeObserver(self, forKeyPath: MLMediaLibraryPropertyKeys.rootMediaGroupKey, context:&rootMediaGroupContext)
self.rootMediaGroup = self.mediaSource.rootMediaGroup
self.rootMediaGroup.addObserver(self,
forKeyPath: MLMediaLibraryPropertyKeys.mediaObjectsKey,
options: NSKeyValueObservingOptions.new,
context: &mediaObjectsContext)
// Obtain the all the photos, (reference returns nil but starts asynchronous loading).
if (self.rootMediaGroup.mediaObjects != nil) {}
}
else if (keyPath == MLMediaLibraryPropertyKeys.mediaObjectsKey && context == &mediaObjectsContext && object! is MLMediaGroup) {
print ("Observe4...................")
// The media objects are loaded, we can now finally access each photo.
// Done observing for media objects that group.
self.rootMediaGroup.removeObserver(self, forKeyPath: MLMediaLibraryPropertyKeys.mediaObjectsKey, context:&mediaObjectsContext)
// Stop progress indicator since we know if we have photos (or not).
self.activityIndicator.isHidden = true
self.activityIndicator.stopAnimation(self)
let mediaObjects = self.rootMediaGroup.mediaObjects
if (mediaObjects != nil && mediaObjects!.count > 0) {
print ("Observe5...................")
// Add photos to the array, to be used in our NSCollectionView.
for mediaObject in mediaObjects! {
if (self.isValidImage(mediaObject)) { // Make sure the media object is a photo.
let title = self.imageTitle(mediaObject)
if let image = NSImage.init(contentsOf: mediaObject.thumbnailURL!) {
let iconItem : Dictionary = [ItemKeys.imageKey: image, ItemKeys.nameKey: title] as [String : Any]
self.arrayController.addObject(iconItem)
}
}
}
self.collectionView.reloadData()
}
else {
// No photos available.
self.noPhotosLabel.isHidden = false
}
self.rootMediaGroup = nil // We are done with this.
}
else {
super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
}
}
}
0 ответов
Делегат NSCollectionViewDataSource отсутствует
класс ViewController: NSViewController, NSCollectionViewDelegate, NSCollectionViewDataSource
Затем вам нужно исправить эти методы: 'numberOfSectionsInCollectionView' был переименован в 'numberOfSections(in:)' 'collectionView(:itemForRepresentObjectAtIndexPath:)' был переименован в 'collectionView (:itemForRepresentObjectAt:)'