使用 UIImagePickerController/ImagePicker 的 iOS Swift 和 Xamarin 应用程序崩溃

Question

我在 iPhone 6s 上使用 Swift 3 拍照时遇到奇怪的问题。我试图一张接一张地拍摄许多照片，最终应用程序崩溃了。

使用以下代码:

import UIKit

class WelcomeViewController : UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate 
{
    var imagePicker: UIImagePickerController!
    var photoCount : Int = 0
    @IBOutlet weak var photoCountLabel: UILabel!
    @IBOutlet weak var memoryUseageLabel: UILabel!

    @IBAction func TakePhotoAction(_ sender: Any) {
        if (imagePicker == nil)
        {
            imagePicker =  UIImagePickerController()
            imagePicker.delegate = self
            imagePicker.sourceType = .camera
        }

        present(imagePicker, animated: true, completion: nil)
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        imagePicker.dismiss(animated: true, completion: nil)
        photoCount = photoCount + 1;

        photoCountLabel.text = String(photoCount)
    }

    override func viewDidLoad(){
        super.viewDidLoad()
        photoCount = 0;

    }
}

我的应用程序崩溃了，xcode 说它与设备“失去了连接”。 因此，一切都表明存在内存泄漏，并且运行仪器表明，这也表明存在一遍又一遍创建的新线程，但它们永远不会完成。

问题是，我使用非常基本的代码，重用选择器，关闭 View ，这是整个应用程序中唯一的 View 。

更奇怪的是，当我在 iOS 10.3.1 上使用 iPhone 7 或在另一部运行 iOS 10.3.2 的 iPhone 6(不是 +)上时，根本不会发生异常

所以我将 6+ 降级到 10.3.1 并再次遇到异常。我什至换上了iOS 11 Beta，仍然出现异常。

我希望有人至少能给我一些关于发生了什么或为什么发生的解释。

更新

我在 Xamarin Forms PCL 项目中遇到了这种情况，并决定将其全部剥离并编写一个 Swift 版本，以查看问题是否仍然发生。事实证明确实如此。无论如何，在测试 Xamarin 应用程序时，我们遇到了异常。

异常已写入日志文件。内容如下:

Error Occurred:
Objective-C exception thrown.  Name: NSInvalidArgumentException Reason: *** setObjectForKey: object cannot be nil (key:         UIImagePickerControllerOriginalImage)
Native stack trace:
0   CoreFoundation                      0x000000018a93eff8 <redacted> + 148
1   libobjc.A.dylib                     0x00000001893a0538 objc_exception_throw + 56
2   CoreFoundation                      0x000000018a822528 <redacted> + 0
3   PhotoLibrary                        0x0000000197b18980 <redacted> + 756
4   PhotoLibrary                        0x0000000197b1864c PLNotifyImagePickerOfImageAvailability + 28
5   CameraUI                            0x00000001a08e990c <redacted> + 456
6   CameraUI                            0x00000001a08e9218 <redacted> + 548
7   UIKit                               0x0000000190aa5010 <redacted> + 96
8   UIKit                               0x0000000190aa4f90 <redacted> + 80
9   UIKit                               0x0000000190a8f504 <redacted> + 440
10  UIKit                               0x0000000190aa4874 <redacted> + 576
11  UIKit                               0x0000000190aa4390 <redacted> + 2480
12  UIKit                               0x0000000190a9f728 <redacted> + 3192
13  UIKit                               0x0000000190a7033c <redacted> + 340
14  UIKit                               0x000000019126a014 <redacted> + 2400
15  UIKit                               0x0000000191264770 <redacted> + 4268
16  UIKit                               0x0000000191264a50 <redacted> + 5004
17  UIKit                               0x0000000191264a50 <redacted> + 5004
18  UIKit                               0x0000000191264b9c <redacted> + 148
19  CoreFoundation                      0x000000018a8ed42c <redacted> + 24
20  CoreFoundation                      0x000000018a8ecd04 <redacted> + 388
21  CoreFoundation                      0x000000018a8ea9a8 <redacted> + 744
22  CoreFoundation                      0x000000018a81ada4 CFRunLoopRunSpecific + 424
23  GraphicsServices                    0x000000018c284074 GSEventRunModal + 100
24  UIKit                               0x0000000190ad5058 UIApplicationMain + 208
25  MyApp_iOS_beta                      0x0000000100bcb634 wrapper_managed_to_native_UIKit_UIApplication_UIApplicationMain_int_string___intptr_intptr + 340
26  MyApp_iOS_beta                      0x000000010050c59c UIKit_UIApplication_Main_string___intptr_intptr + 44
27  MyApp_iOS_beta                      0x000000010050c45c UIKit_UIApplication_Main_string___string_string + 172
28  MyApp_iOS_beta                      0x0000000100078164 MyApp_iOS_Application_Main_string__ + 212
29  MyApp_iOS_beta                      0x00000001011f29f4 wrapper_runtime_invoke_object_runtime_invoke_dynamic_intptr_intptr_intptr_intptr + 244
30  MyApp_iOS_beta                      0x00000001038e504c mono_jit_runtime_invoke + 836
31  MyApp_iOS_beta                      0x000000010394f6b4 do_runtime_invoke + 112
32  MyApp_iOS_beta                      0x00000001039522dc do_exec_main_checked + 152
33  MyApp_iOS_beta                      0x00000001038cea44 mono_jit_exec + 268
34  MyApp_iOS_beta                      0x0000000103a02f70 xamarin_main + 2148
35  MyApp_iOS_beta                      0x00000001038a5e84 main + 96
36  libdyld.dylib                       0x000000018982959c <redacted> + 4

Stack Trace:
  at ObjCRuntime.Runtime.ThrowNSException (System.IntPtr ns_exception) [0x00000] in /Users/builder/data/lanes/4691/d2270eec/source/xamarin-macios/src/ObjCRuntime/Runtime.cs:319 
  at ObjCRuntime.Runtime.throw_ns_exception (System.IntPtr exc) [0x00000] in /Users/builder/data/lanes/4691/d2270eec/source/xamarin-macios/runtime/Delegates.generated.cs:126 
  at (wrapper native-to-managed) ObjCRuntime.Runtime:throw_ns_exception (intptr)
--- End of stack trace from previous location where exception was thrown ---
  at (wrapper managed-to-native) UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
  at UIKit.UIApplication.Main (System.String[] args, System.IntPtr principal, System.IntPtr delegate) [0x00005] in /Users/builder/data/lanes/4691/d2270eec/source/xamarin-macios/src/UIKit/UIApplication.cs:79 
  at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Users/builder/data/lanes/4691/d2270eec/source/xamarin-macios/src/UIKit/UIApplication.cs:63 
  at MyApp.iOS.Application.Main (System.String[] args) [0x00009] in /Users/MyApp/iOS/Main.cs:16 

Answer 1

var image: UIImage? = (info.value(forKey: UIImagePickerControllerOriginalImage) as? UIImage)

使用此键从库中获取原始图像。在原生 iOS 中

这是 Xamarin https://developer.xamarin.com/recipes/ios/media/video_and_photos/choose_a_photo_from_the_gallery/ 的引用