ios - 来自本地通知附件的图像未显示在 UNNotificationContentExtension 中

Question

我一直致力于在 iOS10 中引入丰富的通知体验，并坚持将图像作为附件传递给 UNNotificationContentExtension .

这是我的 ContentExtension:

class NotificationViewController: UIViewController, UNNotificationContentExtension {

    @IBOutlet weak var attachmentImage: UIImageView!

    func didReceive(_ notification: UNNotification) {

        if let attachment = notification.request.content.attachments.first {
            if attachment.url.startAccessingSecurityScopedResource() {
                attachmentImage.image = UIImage(contentsOfFile: attachment.url.path)
                attachment.url.stopAccessingSecurityScopedResource()
            }
        }
    }
}

作为教程，我一直在关注Advanced Notifications video from WWDC .我检查过 - UIImage我正在分配给 UIImageView:

• 不是 nil
• 有适当的CGSize (191x191)
• attachment.url.path 等于 /var/mobile/Library/SpringBoard/PushStore/Attachments/<bundle of app>/<...>.png

以下是我从应用程序发送本地通知的方式:

    let content = UNMutableNotificationContent()
    content.title = "Sample title"
    content.body = "Sample body"
    content.categoryIdentifier = "myNotificationCategory"

    let attachement = try! UNNotificationAttachment(identifier: "image",
                                                                url: Bundle.main.url(forResource: "cat", withExtension: "png")!,
                                                                options: nil)

    content.attachments = [ attachement ]

    let request = UNNotificationRequest(identifier:requestIdentifier, content: content, trigger: nil)
    UNUserNotificationCenter.current().delegate = self
    UNUserNotificationCenter.current().add(request){(error) in
        if (error != nil){
        }
    }

“cat.png”只是我添加到项目中的虚拟资源。

如您所见，通知显示图片，所以我假设我发送正确，但在展开状态(在 NotificationViewController 中)我从未成功显示相同的图片。

我做错了什么？谢谢!

Answer 1

当您使用 contentsOfFile 创建 UIImage 时，UIImage 对象仅读取图像 header ，它指示基本信息，例如图像大小等。

因此，尝试将 stopAccessingSecurityScopedResource 移动到 [NotificationViewController dealloc]。

或使用以下内容:

• objective-c代码:

  NSData *imageData = [NSData dataWithContentsOfURL:imageURL];
  UIImage *image = [UIImage imageWithData:imageData];
  

• swift代码:

  let imageData = NSData(contentsOf: attachment.url)
  let image = UIImage(data: imageData! as Data)
  

没有文档说contentsOfFile 只读图片头。但是当我运行以下代码时:

NSString *docFolderPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
NSString *pngPath = [docFolderPath stringByAppendingPathComponent:@"test.png"];    
UIImage *image = [UIImage imageWithContentsOfFile:pngPath];
[[NSFileManager defaultManager] removeItemAtPath:pngPath error:nil];
imageView.image = image;

发生错误:

ImageIO: createDataWithMappedFile:1322:  'open' failed '/Users/fanjie/Library/Developer/CoreSimulator/Devices/FFDFCA06-A75E-4B54-9FC2-8E2AAE3B1405/data/Containers/Data/Application/E2D26210-4A53-424E-9FE8-D522CFD4FD9E/Documents/test.png'
     error = 2 (No such file or directory)

所以我得出结论，UIImage contentsOfFile 只读取图片头。