imagePickerController 的崩溃断言失败

Question

我正在关注 crashlytics 的崩溃日志和下面的代码。

我知道 fatalError 会使应用程序崩溃。我想问的是，如果sn-p代码有什么问题可能导致错误，我们是否可以避免？

Crashed: com.apple.main-thread
0  libswiftCore.dylib             0x1b013b5c4 _assertionFailure(_:_:file:line:flags:) + 800
1  MyApp                0x1045d7d34 specialized ChatController.imagePickerController(_:didFinishPickingMediaWithInfo:) + 1632 (ChatController.swift:1632)
2  MyApp                0x1045d2c1c @objc ChatController.imagePickerController(_:didFinishPickingMediaWithInfo:) + 4343098396 (<compiler-generated>:4343098396)
3  UIKitCore                      0x1a63368bc -[UIImagePickerController _imagePickerDidCompleteWithInfo:] + 120
4  UIKitCore                      0x1a63361b8 __60-[UIImagePickerController didSelectMediaWithInfoDictionary:]_block_invoke + 48
5  libdispatch.dylib              0x1a25a2ec4 _dispatch_call_block_and_release + 32
6  libdispatch.dylib              0x1a25a433c _dispatch_client_callout + 20
7  libdispatch.dylib              0x1a25b0600 _dispatch_main_queue_callback_4CF + 832
8  CoreFoundation                 0x1a287f41c __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 16
9  CoreFoundation                 0x1a287a034 __CFRunLoopRun + 1708
10 CoreFoundation                 0x1a2879660 CFRunLoopRunSpecific + 480
11 GraphicsServices               0x1acc8a604 GSEventRunModal + 164
12 UIKitCore                      0x1a6a4e15c UIApplicationMain + 1944
13 MyApp                0x1043f37a0 main + 21 (ProfileViewController.swift:21)
14 libdyld.dylib                  0x1a26f51ec start + 4

ChatController.swift：

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any])
{
    
    guard let selectedImage = info[.originalImage] as? UIImage else {
        // Following line is 1632
        fatalError("Error: Expected a dictionary containing an image, but was provided the following: \(info)")
    }
    // other code...
}

Answer 1

很明显，您遇到了崩溃，因为您要求编译器使用fatalError 这样做。如果您想避免崩溃，请删除 fatalError 并处理 originalImage 不可用的事件。

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
    guard let selectedImage = info[.originalImage] as? UIImage else {
        print("Error: Expected a dictionary containing an image, but was provided the following: \(info)")
        // maybe set a placeholder image to the UIImageView
        return
    }
    // other code...
}