为什么当我从斯威夫特3的画廊取照片时，收集视图是空的？
为什么当我从斯威夫特3的画廊取照片时，收集视图是空的？
提问于 2017-06-03 06:27:24
我使用的是斯威夫特3，希望在收藏视图中看到图片库的图像，但是这些代码对我不起作用。
在看到我的代码注意到：**我不会收到任何错误或崩溃，我只是无法在集合视图中看到我的任何图像库**这里是我的代码：
import UIKit
import Photos
class collectionImageViewController: UIViewController , UICollectionViewDataSource , UICollectionViewDelegate {
var imageArray = [UIImage]()
@IBOutlet weak var collectionImageView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return imageArray.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CollectionViewImageCell", for: indexPath) as! CollectionViewImageCell
cell.theImage.image = imageArray[indexPath.row]
return cell
}
func getPhotosFromAlbum() {
let imageManager = PHImageManager.default()
let requestOptions = PHImageRequestOptions()
requestOptions.isSynchronous = true
requestOptions.deliveryMode = .highQualityFormat
let fetchOptions = PHFetchOptions()
fetchOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
let fetchResult: PHFetchResult = PHAsset.fetchAssets(with: .image, options: fetchOptions)
if fetchResult.count > 0 {
for i in 0..<fetchResult.count {
imageManager.requestImage(for: fetchResult.object(at: i), targetSize: CGSize(width: 300, height: 300), contentMode: .aspectFill, options: requestOptions, resultHandler: { image, error in
self.imageArray.append(image!)
})
}
} else {
self.collectionImageView?.reloadData()
}
}回答 2
Stack Overflow用户
回答已采纳
发布于 2017-06-03 06:43:44
这是我从图片库加载所有图像并加载到集体视图的全部代码。请看这段代码
import UIKit
import Photos
class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {
let arr_img = NSMutableArray()
@IBOutlet var collview: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
let allPhotosOptions : PHFetchOptions = PHFetchOptions.init()
allPhotosOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: true)]
let allPhotosResult = PHAsset.fetchAssets(with: .image, options: allPhotosOptions)
allPhotosResult.enumerateObjects({ (asset, idx, stop) in
self.arr_img.add(asset)
})
}
func getAssetThumbnail(asset: PHAsset, size: CGFloat) -> UIImage {
let retinaScale = UIScreen.main.scale
let retinaSquare = CGSize(width: size * retinaScale, height: size * retinaScale)//CGSizeMake(size * retinaScale, size * retinaScale)
let cropSizeLength = min(asset.pixelWidth, asset.pixelHeight)
let square = CGRect(x: 0, y: 0, width: cropSizeLength, height: cropSizeLength)//CGRectMake(0, 0, CGFloat(cropSizeLength), CGFloat(cropSizeLength))
let cropRect = square.applying(CGAffineTransform(scaleX: 1.0/CGFloat(asset.pixelWidth), y: 1.0/CGFloat(asset.pixelHeight)))
let manager = PHImageManager.default()
let options = PHImageRequestOptions()
var thumbnail = UIImage()
options.isSynchronous = true
options.deliveryMode = .highQualityFormat
options.resizeMode = .exact
options.normalizedCropRect = cropRect
manager.requestImage(for: asset, targetSize: retinaSquare, contentMode: .aspectFit, options: options, resultHandler: {(result, info)->Void in
thumbnail = result!
})
return thumbnail
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
//MARK:
//MARK: Collectioview methods
func collectionView(_ collectionView: UICollectionView,
numberOfItemsInSection section: Int) -> Int {
return arr_img.count
}
func collectionView(_ collectionView: UICollectionView,
cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell",
for: indexPath)
let imgview : UIImageView = cell.viewWithTag(20) as! UIImageView
imgview.image = self.getAssetThumbnail(asset: self.arr_img.object(at: indexPath.row) as! PHAsset, size: 150)
return cell
}
}Stack Overflow用户
发布于 2017-06-03 06:32:46
必须在for循环之后重新加载collectionView，如下所示
...
{
for i in 0..<fetchResult.count {
imageManager.requestImage(for: fetchResult.object(at: i), targetSize: CGSize(width: 300, height: 300), contentMode: .aspectFill, options: requestOptions, resultHandler: { image, error in
self.imageArray.append(image!)
})
self.collectionImageView?.reloadData()
}
...页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/44341028
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