Question

请在下面的代码中帮助我。我收到了一个错误：

表达式类型“（_，_） - ＆gt; Void”在没有更多上下文的情况下是不明确的。

import UIKit
import SDWebImage

class CustomImageView: UIImageView {
    let progressIndicatorView = CircularLoaderView(frame: CGRect.zero)

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)!

        addSubview(self.progressIndicatorView)
        progressIndicatorView.frame = bounds
        progressIndicatorView.autoresizingMask = [.flexibleWidth, .flexibleHeight]

        let url = NSURL(string: "http://png-3.findicons.com/files/icons/2795/office_2013_hd/2000/word.png")
        self.sd_setImage(with: url as URL?, placeholderImage: nil, options: .cacheMemoryOnly, progress: { [weak self] (receivedSize, expectedSize) -> Void in
            self.progressIndicatorView.progress = CGFloat(receivedSize)/CGFloat(expectedSize)
        }) { [weak self](image, error, _, _) -> Void in
            self.progressIndicatorView.reveal()
        }
    }
}

Answer 1

将Future<User> getUser(String tag) async { String base = '/1.1/users/show.json'; final response = await _twitterGet(base, [ ["screen_name", tag], ["tweet_mode", "extended"] ]); if (response.statusCode == 200) { try { return User(json.decode(response.body)); } catch (e) { print(e); return null; } } else { print("Error retrieving user"); print(response.body); return null; } }更改为NSURL应该可以！

Answer 2

我认为它引用了[weak self] (receivedSize, expectedSize) -> Void in，这意味着函数sd.setImage()有多个progress参数类型。

你可以通过明确地描述receivedSize和expectedSize的类型来解决这个问题，就像[weak self] (receivedSize: Type1, expectedSize: Type2) -> Void in一样。

Answer 3

因为你缺少来自progressBlock的另外一个参数。检查这个

import UIKit

导入SDWebImage

class CustomImageView：UIImageView { 让progressIndicatorView = CircularLoaderView（frame：CGRect.zero）

required init(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)!

    addSubview(self.progressIndicatorView)
    progressIndicatorView.frame = bounds
    progressIndicatorView.autoresizingMask = [.flexibleWidth, .flexibleHeight]

    let url = URL(string: "http://png-3.findicons.com/files/icons/2795/office_2013_hd/2000/word.png")!
    self.sd_setImage(with: url, placeholderImage: nil, options: .cacheMemoryOnly, progress: { (receivedSize, expectedSize, _) in
        self.progressIndicatorView.progress = CGFloat(receivedSize)/CGFloat(expectedSize)
    }) { (image, error, _, _) in

    }
}

}

看到他们应该有三个正在进行中。

表达式类型“（_，_） - ＆gt; Void”在没有更多上下文的情况下是模糊的

3 个答案: