创建快速关闭并将其作为完成块传递给Objective-C类 [英] Create swift closure and pass it to objective-c class as completion block

问题描述

现在，我正在基于Objective-C的iOS应用程序中添加Swift代码。

但是从Swift端调用Objective-C方法时遇到问题。 / p>

我想在 View UIImageView 上绘制图像$ c>或 ViewController 用Swift编写。
另一方面，我的照片库包装器类是用Objective-C编写的。

我的照片库包装器类如下。

・ MyPhotoLibraryMgr.h

  typedef void（^ AppPhotoLibraryGetImageCompletion）（UIImage * image，NSError *错误）; 
 
-（void）getImageWithTarget：（NSInteger）index 
 targetSize：（CGSize）targetSize 
完成：（AppPhotoLibraryGetImageCompletion）完成; 
  

・ MyPhotoLibraryMgr.m

 -（void）getImageWithTarget：（NSInteger）index 
 targetSize：（CGSize）targetSize 
完成时间：
（AppPhotoLibraryGetImageCompletion）完成
 {
 PHAsset * asset = _myAsetsList [index]; 
 
 PHImageRequestOptions * options = [[PHImageRequestOptions alloc] init]; 
 options.resizeMode = PHImageRequestOptionsResizeModeFast; 
 options.deliveryMode = PHImageRequestOptionsDeliveryModeOpportunistic; 
 
 [[PHImageManager defaultManager] requestImageForAsset：asset 
 targetSize：targetSize 
 contentMode：PHImageContentModeAspectFill 
 options：options 
 resultHandler：^（UIImage * result，NSDictionary * info）{
 NSError * error = [info objectForKey：PHImageErrorKey]; 
 if（error）{
 NSLog（@ error =％@，error）; 
} 
完成（结果，错误）； 
}]； 
} 
  

我可以在 View中获取并绘制图像或 ViewController ，如下所示，

・ MyViewController.m

  AppPhotoLibraryMgr * photoLibMgr = [AppPhotoLibraryMgr sharedInstance]; 
 AppPhotoLibraryGetImageCompletion完成= ^（UIImage * image，NSError * error）{
 imageView.image = image; 
}; 
 
 [[AppPhotoLibraryMgr sharedInstance] getImageWithTarget：index 
 targetSize：imageView.frame.size 
 complete：completion]; 
  

但是我无法在 View 或用Swift编写的 ViewController 。

・ MySwiftViewController.swift

 让完成完成= {{image：UIImage，error：NSError）-> 
中的AppPhotoLibraryGetImageCompletion让imageView = UIImageView（image：image）
} 
 
 photoLibMgr？.getImageWithTarget（index，targetSize：size，complete：completion）
  

来自Xcode的错误消息是

---

无法将类型'UIImage，NSError->
AppPhotoLibraryGetImageCompletion的值转换为预期的参数类型
'AppPhotoLibraryGetImageCompletion'

解决方案

您的 completion 变量声明在 MySwiftViewController.swift中是错误的文件。

像这样编辑它：

 让完成：AppPhotoLibraryGetImageCompletion = {（图像，错误）在
中，让imageView = UIImageView（image：image）
} 
  

OR

如果您不想将完成处理程序声明为变量，则只需执行以下操作：

 李nphoneLoginController.shared（）。getImageWithTarget（index，targetSize：size）{（图像，错误）在
中，让imageView = UIImageView（image：image）
} 
  

Now I'm adding Swift code on objective-C based iOS application.

But I have a problem in calling the objective-C method from Swift side.

I'd like to get and draw image on UIImageView in View or ViewController which is written with Swift. On the other hand my wrapper class of Photos Library is written with objective-C.

My wrapper class of Photos Library is below.

・MyPhotoLibraryMgr.h

typedef void (^AppPhotoLibraryGetImageCompletion)(UIImage *image, NSError *error);

- (void)getImageWithTarget:(NSInteger)index
                targetSize:(CGSize)targetSize
                completion:(AppPhotoLibraryGetImageCompletion)completion;

・MyPhotoLibraryMgr.m

- (void)getImageWithTarget:(NSInteger)index
                targetSize:(CGSize)targetSize
                completion:
(AppPhotoLibraryGetImageCompletion)completion
{
    PHAsset *asset = _myAsetsList[index];

    PHImageRequestOptions *options = [[PHImageRequestOptions alloc] init];
    options.resizeMode = PHImageRequestOptionsResizeModeFast;
    options.deliveryMode = PHImageRequestOptionsDeliveryModeOpportunistic;

    [[PHImageManager defaultManager] requestImageForAsset:asset
                                               targetSize:targetSize
                                              contentMode:PHImageContentModeAspectFill
                                                  options:options
                                            resultHandler:^(UIImage *result, NSDictionary *info) {
                                                NSError *error = [info objectForKey:PHImageErrorKey];
                                                if (error) {
                                                    NSLog(@"error=%@", error);
                                                }
                                                completion(result, error);
                                            }];
}

I can get and draw image in View or ViewController written by objective-C like below,

・MyViewController.m

AppPhotoLibraryMgr *photoLibMgr = [AppPhotoLibraryMgr sharedInstance];
AppPhotoLibraryGetImageCompletion completion = ^(UIImage *image, NSError *error) {
                imageView.image = image;
};

[[AppPhotoLibraryMgr sharedInstance] getImageWithTarget:index
                                             targetSize:imageView.frame.size
                                             completion:completion];

But I can't get image in View or ViewController written in Swift.

・MySwiftViewController.swift

let completion = {(image: UIImage, error: NSError) -> AppPhotoLibraryGetImageCompletion in
    let imageView = UIImageView(image: image)
}

photoLibMgr?.getImageWithTarget(index, targetSize: size, completion: completion)

Error message from Xcode is

---

Cannot convert value of type 'UIImage, NSError -> AppPhotoLibraryGetImageCompletion" to expected argument type 'AppPhotoLibraryGetImageCompletion'

解决方案

Your declaration of completion variable is wrong in MySwiftViewController.swift file.
Edit it like this:

let completion: AppPhotoLibraryGetImageCompletion = { (image, error) in
   let imageView = UIImageView(image: image)
}

OR
If you don't want to declare completion handler as variable, then simply do the:

LinphoneLoginController.shared().getImageWithTarget(index, targetSize: size) { (image, error) in
    let imageView = UIImageView(image: image)
}

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