ios - "null"时显示白色图像的 ImageURL

Question

当图像 URL 为空时，我想显示一个名为“Tap_Edit_Profile”的默认图像，但我不确定为什么当它为空时，它显示一张白色图片。这是我在代码中遗漏了什么吗？

 if let imageURL = self.currentAgent.userPictureURL {
            if imageURL != "null" {
                self.userPicture.setImageWithURLString(string: imageURL, shouldFadeIn: true)

            }
            else {
                self.userPicture.image = UIImage(named: "Tap_Edit_Profile")     }

下面是我的 setImageWithURLString 函数:

    func setImageWithURLString(string: String?, placeholderImage: UIImage? = nil ,shouldFadeIn fade: Bool, withDuration duration: TimeInterval = 0.5, completionBlock: (() -> Void)? = nil) {

    if let string = string {
        if let url: URL = URL(string: string) {
            if SDWebImageManager.shared().cachedImageExists(for: url) || fade == false {
                self.alpha = 1
            } else {
                self.alpha = 0
            }

            self.sd_setImage(with: url, placeholderImage: placeholderImage, options: .retryFailed, completed: { (image, error, type, url) in
                completionBlock?()
                if type == SDImageCacheType.none {
                    UIView.animate(withDuration: duration, animations: {
                        self.alpha = 1
                    })
                } else {
                    self.alpha = 1
                }
            })
            return
        }
    }
    if fade {
        UIView.animate(withDuration: duration, animations: { self.alpha = 1 })
    }
}

imageURL 没有任何图像，因此它不应该显示我的“Tap_Edit_Profile”默认图像吗？提前谢谢大家

Answer 1

我认为您正在使用 SDWebImage 从 url 加载图像。默认情况下，库提供了一个选项来设置默认图像。这是代码

self.profilePicture.sd_setImage(with: URL(string: "url"), placeholderImage: UIImage(named: "Tap_Upload_Photo.png"))