Question

使用SDWebImage下载图片。如果成功下载图像，我想进一步操作。

cell.appIcon.sd_setImage(with: url, placeholderImage: UIImage.init(named: "App-Default"), completed: {(image: UIImage!, error: NSError!, cacheType: SDImageCacheType, imageURL: URL!) -> Void in
      // Perform operation. 
})

但我收到错误：

无法转换类型'的值（UIImage！，NSError！，SDImageCacheType，URL！） - ＆gt; Void'到预期的参数类型'SDExternalCompletionBlock？'

Answer 1

终于解决了。

cell.appIcon.sd_setImage(with: url!, placeholderImage: UIImage(named: "App-Default"),options: SDWebImageOptions(rawValue: 0), completed: { (image, error, cacheType, imageURL) in
 // Perform operation.
})

Answer 2

SWIFT 4 版本

cell.appIcon.sd_setImage(with: url, placeholderImage: UIImage(named: "App-Default"),options: SDWebImageOptions(rawValue: 0), completed: { image, error, cacheType, imageURL in
     // your rest code
})

重要！ 当有必要时，不要忘记将自我作为弱或无主（如此[自我弱] / [自己无主]）发送到块中，以避免保留周期。

示例：

cell.appIcon.sd_setImage(
     with: url,
     placeholderImage: UIImage(named: "App-Default"),
     options: SDWebImageOptions(rawValue: 0),
     completed: { [self weak] image, error, cacheType, imageURL in
                  guard let selfNotNil = self else { return }
                  // your rest code
        }
)

Answer 3

根据您使用的框架中的typedef：

typedef void(^SDExternalCompletionBlock)(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL);

SDExternalCompletionBlock由_Nullable指示的可选参数组成。因此，您的代码应该是这样写的：

cell.appIcon.sd_setImage(with: url, placeholderImage: UIImage.init(named: "App-Default"), completed: {(image: UIImage?, error: NSError?, cacheType: SDImageCacheType, imageURL: URL?) -> Void in
      // Perform operation. 
})

由于编译器知道完成块参数的类型（来自函数声明），您可以更简洁地编写代码，并且（IMO）更容易阅读，如下所示：

cell.appIcon.sd_setImage(with: url, placeholderImage: UIImage(named: "App-Default"), completed: { (image, error, cacheType, imageURL) in
      // Perform operation. 
})

Answer 4

这个也适用于swift 3：

cell.appIcon.sd_setImage(with: url, placeholderImage: UIImage(named: "App-Default"), options: []) { (image, error, imageCacheType, imageUrl) in
            // Perform your operations here.
}

Answer 5

cell.appIcon.sd_setImage(with: url, placeholderImage: UIImage(named: "App-Default"),options: SDWebImageOptions(rawValue: 0), completed: { (img, err, cacheType, imgURL) in
     // code
})

试试这个，希望这样可以正常使用

如何在Swift 3.0中使用SDWebImage完成块？

5 个答案: