Swift 相位设置为UIImage

我试图从一个相集创建一个UIImage（比如缩略图或其他东西），这样我就可以将它传递到一个获取UIImage的东西中。我已经尝试过调整我在SO上找到的解决方案（因为它们都只是直接将其传递到tableview或其他东西中），但没有成功（可能是因为我做得不对）

打印人员告诉我manager.request行现在没有做任何事情。如何让它将资产作为UIImage提供给我

---

谢谢。

问题在于requestImageForAsset是一个resultHandler，这段代码将在函数打印并返回预期值后发生。我来这里是为了向你们展示这种情况，并提出一些简单的解决方案

func getAssetThumbnail(asset: PHAsset) {
    var retimage = UIImage()
    println(retimage)
    let manager = PHImageManager.defaultManager()
    manager.requestImageForAsset(asset, targetSize: CGSize(width: 100.0, height: 100.0), contentMode: .AspectFit, options: nil, resultHandler: {
    (result, info)->Void in
            retimage = result
      println("This happens after")
      println(retimage)
      callReturnImage(retimage) // <- create this method
    })
    println("This happens before")
}

func getAssetThumbnail（资产：PHAsset）{
var retimage=UIImage（）
println（重成像）
let manager=PHImageManager.defaultManager（）
manager.requestImageForAsset（资产，targetSize:CGSize（宽度：100.0，高度：100.0），contentMode:.AspectFit，选项：nil，resultHandler:{
（结果，信息）->在中无效
重成像=结果
println（“这发生在之后”）
println（重成像）
callReturnImage（retimage）//这就是我需要它做的，以防任何人也需要它

func getAssetThumbnail(asset: PHAsset) -> UIImage {
    let manager = PHImageManager.defaultManager()
    let option = PHImageRequestOptions()
    var thumbnail = UIImage()
    option.synchronous = true
    manager.requestImageForAsset(asset, targetSize: CGSize(width: 100.0, height: 100.0), contentMode: .AspectFit, options: option, resultHandler: {(result, info)->Void in
            thumbnail = result!
    })
    return thumbnail
}

编辑：Swift 3更新
我建议使用苹果的（继承自PHImageManager）：

PHCachingImageManager对象为照片或视频资产获取或生成图像数据

另外，phcachingimanager支持更好的缓存机制

获取缩略图的示例：

let options = PHImageRequestOptions()
options.deliveryMode = .HighQualityFormat
options.synchronous = true // Set it to false for async callback

let imageManager = PHCachingImageManager()
imageManager.requestImageForAsset(YourPHAssetVar,
                                  targetSize: CGSizeMake(CGFloat(160), CGFloat(160)),
                                  contentMode: .AspectFill,
                                  options: options,
                                  resultHandler: { (resultThumbnail : UIImage?, info : [NSObject : AnyObject]?) in

                                                   // Assign your thumbnail which is the *resultThumbnail*
                                                  }

此外，您还可以使用PHCachingImageManager来缓存图像，以实现更快的UI响应：

要使用缓存图像管理器，请执行以下操作：

创建PHCachingImageManager实例。（此步骤替换使用
共享的PHImageManager实例。）

使用PHAsset类方法获取您感兴趣的资产

要为这些资产准备图像，请调用
StartChinaGimagesForasets:targetSize:contentMode:options:method
具有目标大小、内容模式和您计划在以下情况下使用的选项：
稍后为每个单独的资产请求图像

当您需要单个资产的图像时，请调用
requestImageForAsset:targetSize:contentMode:options:resultHandler:
方法，并传递准备时使用的相同参数
资产

如果您请求的图像是已经准备好的图像，则
PHCachingImageManager对象立即返回该图像。
否则，照片会按需准备图像并将其缓存以备以后使用
使用

在我们的例子中：

var phAssetArray : [PHAsset] = []

for i in 0..<assets.count
{
  phAssetArray.append(assets[i] as! PHAsset)
}

let options = PHImageRequestOptions()
options.deliveryMode = .Opportunistic
options.synchronous = false

self.imageManager.startCachingImagesForAssets(phAssetArray,
                                              targetSize: CGSizeMake(CGFloat(160), CGFloat(160)),
                                              contentMode: .AspectFill,
                                              options: options)

var phAssetArray:[PHAsset]=[]
对于Swift 3.0.1中的i..

func getAssetThumbnail(asset: PHAsset, size: CGFloat) -> UIImage {
    let retinaScale = UIScreen.main.scale
    let retinaSquare = CGSize(width: size * retinaScale, height: size * retinaScale)//(size * retinaScale, size * retinaScale)
    let cropSizeLength = min(asset.pixelWidth, asset.pixelHeight)
    let square = CGRect(x:0, y: 0,width: CGFloat(cropSizeLength),height: 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
}

参考资料：
试试这个，它对我有用，希望它也能帮助你

func getUIImage(asset: PHAsset) -> UIImage? {

    var img: UIImage?
    let manager = PHImageManager.default()
    let options = PHImageRequestOptions()
    options.version = .original
    options.isSynchronous = true
    manager.requestImageData(for: asset, options: options) { data, _, _, _ in

        if let data = data {
            img = UIImage(data: data)
        }
    }
    return img
}

Objective-c版代码基于dcheng答案

-(UIImage *)getAssetThumbnail:(PHAsset * )asset {

    PHImageRequestOptions *options = [[PHImageRequestOptions alloc]init];
    options.synchronous = true;

    __block UIImage *image;
    [PHCachingImageManager.defaultManager requestImageForAsset:asset targetSize:CGSizeMake(100, 100) contentMode:PHImageContentModeAspectFit options:options resultHandler:^(UIImage * _Nullable result, NSDictionary * _Nullable info) {
        image = result;
    }];
    return image;
  }

斯威夫特4

resizeMode
，
deliveryMode
-可根据用户需求进行设置

isNetworkAccessAllowed
-将此设置为“true”以从云中获取图像

imageSize
-所需的图像大小

func getImageFromAsset(asset:PHAsset,imageSize:CGSize, callback:@escaping (_ result:UIImage) -> Void) -> Void{

    let requestOptions = PHImageRequestOptions()
    requestOptions.resizeMode = PHImageRequestOptionsResizeMode.fast
    requestOptions.deliveryMode = PHImageRequestOptionsDeliveryMode.highQualityFormat
    requestOptions.isNetworkAccessAllowed = true
    requestOptions.isSynchronous = true
    PHImageManager.default().requestImage(for: asset, targetSize: imageSize, contentMode: PHImageContentMode.default, options: requestOptions, resultHandler: { (currentImage, info) in
        callback(currentImage!)
    })
}

简单解决方案（Swift 4.2）

方法1:

extension PHAsset {

    var image : UIImage {
        var thumbnail = UIImage()
        let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { image, _ in
            thumbnail = image!
        })
        return thumbnail
    }
}                          

let image = asset.image 

extension PHAsset {
    var data : (UIImage, [AnyHashable : Any]) {
        var img = UIImage(); var information = [AnyHashable : Any](); let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { image,info in
            img = image!
            information = info!
        })
        return (img,information)
    }
} 


let image_withData : (UIImage, [AnyHashable : Any]) = asset.data

如果您只需要从
PHAsset
获取
UIImage
，请使用此方法

或

extension PHAsset {
    func image(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?) -> UIImage {
        var thumbnail = UIImage()
        let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: targetSize, contentMode: contentMode, options: options, resultHandler: { image, _ in
            thumbnail = image!
        })
        return thumbnail
    }
}

let image = asset.image(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?)

extension PHAsset {

    func image(completionHandler: @escaping (UIImage) -> ()){
        var thumbnail = UIImage()
        let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { img, _ in
            thumbnail = img!
        })
        completionHandler(thumbnail)
    }
}

let image = asset.image(completionHandler: {(img) in
    print("Finished")
})

extension PHAsset {

    func data(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?) -> (UIImage, [AnyHashable : Any]) {
        var img = UIImage(); var information = [AnyHashable : Any](); let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: targetSize, contentMode: contentMode, options: options, resultHandler: { image,info in
            img = image!
            information = info!
        })
        return (img,information)
    }
}

let data = asset?.data(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?)

将此方法用于所需的
UIImage

或

extension PHAsset {
    func image(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?) -> UIImage {
        var thumbnail = UIImage()
        let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: targetSize, contentMode: contentMode, options: options, resultHandler: { image, _ in
            thumbnail = image!
        })
        return thumbnail
    }
}

let image = asset.image(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?)

extension PHAsset {

    func image(completionHandler: @escaping (UIImage) -> ()){
        var thumbnail = UIImage()
        let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { img, _ in
            thumbnail = img!
        })
        completionHandler(thumbnail)
    }
}

let image = asset.image(completionHandler: {(img) in
    print("Finished")
})

extension PHAsset {

    func data(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?) -> (UIImage, [AnyHashable : Any]) {
        var img = UIImage(); var information = [AnyHashable : Any](); let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: targetSize, contentMode: contentMode, options: options, resultHandler: { image,info in
            img = image!
            information = info!
        })
        return (img,information)
    }
}

let data = asset?.data(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?)

使用此方法在完成后通知

方法2:

extension PHAsset {

    var image : UIImage {
        var thumbnail = UIImage()
        let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { image, _ in
            thumbnail = image!
        })
        return thumbnail
    }
}                          

let image = asset.image 

extension PHAsset {
    var data : (UIImage, [AnyHashable : Any]) {
        var img = UIImage(); var information = [AnyHashable : Any](); let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { image,info in
            img = image!
            information = info!
        })
        return (img,information)
    }
} 


let image_withData : (UIImage, [AnyHashable : Any]) = asset.data

如果需要
UIImage
和
PHAsset

或

extension PHAsset {
    func image(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?) -> UIImage {
        var thumbnail = UIImage()
        let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: targetSize, contentMode: contentMode, options: options, resultHandler: { image, _ in
            thumbnail = image!
        })
        return thumbnail
    }
}

let image = asset.image(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?)

extension PHAsset {

    func image(completionHandler: @escaping (UIImage) -> ()){
        var thumbnail = UIImage()
        let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: CGSize(width: 100, height: 100), contentMode: .aspectFit, options: nil, resultHandler: { img, _ in
            thumbnail = img!
        })
        completionHandler(thumbnail)
    }
}

let image = asset.image(completionHandler: {(img) in
    print("Finished")
})

extension PHAsset {

    func data(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?) -> (UIImage, [AnyHashable : Any]) {
        var img = UIImage(); var information = [AnyHashable : Any](); let imageManager = PHCachingImageManager()
        imageManager.requestImage(for: self, targetSize: targetSize, contentMode: contentMode, options: options, resultHandler: { image,info in
            img = image!
            information = info!
        })
        return (img,information)
    }
}

let data = asset?.data(targetSize: CGSize, contentMode: PHImageContentMode, options: PHImageRequestOptions?)

对所需数据使用此方法。
Swift 5

extension PHAsset {
func getAssetThumbnail() -> UIImage {
    let manager = PHImageManager.default()
    let option = PHImageRequestOptions()
    var thumbnail = UIImage()
    option.isSynchronous = true
    manager.requestImage(for: self,
                         targetSize: CGSize(width: self.pixelWidth, height: self.pixelHeight),
                         contentMode: .aspectFit,
                         options: option,
                         resultHandler: {(result, info) -> Void in
                            thumbnail = result!
                         })
    return thumbnail
    }
}

仍然有点困惑。所以我们正在更改getAssetThumbnail以不返回任何内容？在这种情况下，我们将如何将重映像传递给我们需要的内容？何时以及如何执行该块以获得有用的内容。希望callReturnImage与我们尝试将重映像传递给的其他函数分开。您不能返回在检索之前，您的返回将发生，请添加另一个函数，该函数可以对图像执行您想要执行的操作，或者在完成块中添加您想要对图像执行的操作。这是解决此问题的两种更简单的方法。对。好吧，假设我有两个函数（x&y）这两个都需要UIImages。我希望它们对我们在该块中创建的UIImages进行操作。我是否不可能在该块之外通过将UIImages传递到x&y并从请求方法获取该图像来完成此操作？或者我必须将x&y作为您暗示的callReturnImage函数。如果不可能，那么如果我是要在将来创建函数z，我不是必须回去编辑这个函数才能工作吗？我不是说这是不可能的，我是说这是一种更简单的方法，你可以创建函数，也可以返回完成块，但问题对你来说只会变得更大，我会在答案中发布一个链接，这样你就可以了解更多le，假设我想这样做：var image=a.getAssetThumbnail（firstAsset）我如何才能做到这一点？如果有人需要更多信息，请查看苹果的示例代码：如何获得相位集的原始宽度+高度？我还想知道如何获得原始宽度和高度，您找到解决方案了吗，@TimNuwin？如果您谈论的是pixelWidth和pixelHeight属性，那么这就是您要使用的。如果不是，我需要更多的信息来帮助。希望这个链接有帮助：你可以通过设置PHImageManagerMaximumSize为targetSize来获取原始图像。@BorutTomazin我似乎遇到了一个奇怪的崩溃，
这个应用程序在从主线程访问引擎后从后台线程修改自动布局引擎。这可能会导致d导致引擎损坏和奇怪的崩溃。
当我更改
targetSize
时，我收到了错误“