Holen Sie Bilder aus dem Internet in eine Sammlung

Question

Hallo alles, was ich lerne, indem ich versuche zu schaffen. Ich habe einen Demo-Code, mit dem ich arbeite und wollte wissen, ob es eine Möglichkeit gibt, das angezeigte Bild (hart geschrieben) (Namen der Autos) zu ändern und es so zu ändern, dass stattdessen ein Bild von einer URL angezeigt wird. weil ich newt dieses Zeug bin ich versuche zu lernen und kann Beispiele dafür, wie es für andere Dinge zu tun, aber scheint es schwer zu bekommen, es in diesen Code zu bekommen. Ich hoffe du kannst helfen.

Ich habe eine Klasse Anruf Post und ich bekomme Bilder von Firebase. Also verwende ich: post.imageUrl1 für die Bild-URL.

class DemoViewController: ExpandingViewController { 
@IBAction func backPressed(_ sender: Any) { 
} 

    var post: Post! 

typealias ItemInfo = (imageName: String, title: String) 
fileprivate var cellsIsOpen = [Bool]() 
fileprivate let items: [ItemInfo] = [("Ferrari", "Ferrari"),("Bug", "Bugatti"),("car", "Mustang"),("BM", "BMW")] 

@IBOutlet weak var pageLabel: UILabel! 
@IBOutlet weak var titleImageView: UIImageView! 
@IBOutlet weak var titleImageViewXConstraint: NSLayoutConstraint! 

} 

// MARK: - Lifecycle 
extension DemoViewController { 



override func viewDidLoad() { 
itemSize = CGSize(width: 256, height: 335) 
super.viewDidLoad() 




registerCell() 
fillCellIsOpenArray() 
addGesture(to: collectionView!) 
configureNavBar() 
} 

override func viewWillLayoutSubviews() { 
super.viewWillLayoutSubviews() 
guard let titleView = navigationItem.titleView else { return } 
let center = UIScreen.main.bounds.midX 
let diff = center - titleView.frame.midX 
titleImageViewXConstraint.constant = diff 
} 


} 

// MARK: Helpers 
extension DemoViewController { 

fileprivate func registerCell() { 

    let nib = UINib(nibName: String(describing:  DemoCollectionViewCell.self), bundle: nil) 
collectionView?.register(nib, forCellWithReuseIdentifier: String(describing: DemoCollectionViewCell.self)) 
    } 

    fileprivate func fillCellIsOpenArray() { 
    cellsIsOpen = Array(repeating: false, count: items.count) 
    } 

fileprivate func getViewController() -> ExpandingTableViewController { 
let storyboard = UIStoryboard(storyboard: .Main) 
let toViewController: DemoTableViewController = storyboard.instantiateViewController() 
return toViewController 
} 

fileprivate func configureNavBar() { 
navigationItem.leftBarButtonItem?.image = navigationItem.leftBarButtonItem?.image!.withRenderingMode(UIImageRenderingMode.alwaysOriginal) 
} 

} 

/// MARK: Gesture 
extension DemoViewController { 

fileprivate func addGesture(to view: UIView) { 
let upGesture = Init(UISwipeGestureRecognizer(target: self, action: #selector(DemoViewController.swipeHandler(_:)))) { 
    $0.direction = .up 
} 

let downGesture = Init(UISwipeGestureRecognizer(target: self, action: #selector(DemoViewController.swipeHandler(_:)))) { 
    $0.direction = .down 
} 
view.addGestureRecognizer(upGesture) 
view.addGestureRecognizer(downGesture) 
} 

func swipeHandler(_ sender: UISwipeGestureRecognizer) { 
let indexPath = IndexPath(row: currentIndex, section: 0) 
guard let cell = collectionView?.cellForItem(at: indexPath) as? DemoCollectionViewCell else { return } 
// double swipe Up transition 
if cell.isOpened == true && sender.direction == .up { 
    pushToViewController(getViewController()) 

    if let rightButton = navigationItem.rightBarButtonItem as? AnimatingBarButton { 
    rightButton.animationSelected(true) 
    } 
    } 

    let open = sender.direction == .up ? true : false 
    cell.cellIsOpen(open) 
    cellsIsOpen[indexPath.row] = cell.isOpened 
    } 

    } 

// MARK: UIScrollViewDelegate 
extension DemoViewController { 

func scrollViewDidScroll(_ scrollView: UIScrollView) { 
pageLabel.text = "\(currentIndex+1)/\(items.count)" 
} 

} 

// MARK: UICollectionViewDataSource 
extension DemoViewController { 



override func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) { 
super.collectionView(collectionView, willDisplay: cell, forItemAt: indexPath) 
guard let cell = cell as? DemoCollectionViewCell else { return } 

let index = indexPath.row % items.count 
let info = items[index] 
cell.backgroundImageView?.image = UIImage(named: info.imageName) 
cell.customTitle.text = info.title 
cell.cellIsOpen(cellsIsOpen[index], animated: false) 
} 

func collectionView(_ collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: IndexPath) { 
guard let cell = collectionView.cellForItem(at: indexPath) as? DemoCollectionViewCell 
     , currentIndex == indexPath.row else { return } 

if cell.isOpened == false { 
    cell.cellIsOpen(true) 
} else { 
    pushToViewController(getViewController()) 

    if let rightButton = navigationItem.rightBarButtonItem as? AnimatingBarButton { 
    rightButton.animationSelected(true) 
    } 
    } 
} 

} 

// MARK: UICollectionViewDataSource 
extension DemoViewController { 

override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { 
return items.count 
} 

override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { 
return collectionView.dequeueReusableCell(withReuseIdentifier: String(describing: DemoCollectionViewCell.self), for: indexPath) 

    } 

} 

Answer 1

Sie ein Bild von einer URL herunterladen kann den benannten Konstruktor von Daten mit: let imageData = Data(contentsOf: "exampleURL.com")

Dann ist dies Sie gerade anzeigen Datenquelle Methode in Ihrer Sammlung verwenden:

für swift2

override func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) { 
    super.collectionView(collectionView, willDisplay: cell, forItemAt: indexPath) 
    guard let cell = cell as? DemoCollectionViewCell else { return } 

    let index = indexPath.row % items.count 
    let info = items[index] 
    //here I assumed you would create a .url property of ItemInfo, but you can access the URL any way you want to 
    guard let imageUrl = URL(string: info.url) else { return } 
    do { 
     let imageData = try Data(contentsOf: imageUrl) 
    } catch { 
     //handle error here 
    } 
    cell.backgroundImageView?.image = UIImage(data: imageData) 
    cell.customTitle.text = info.title 
    cell.cellIsOpen(cellsIsOpen[index], animated: false) 
}