存储对相机胶卷图像的引用 - Swift 4

Question

我有一个非常简单的请求，显然超出了我的能力范围。我要做的就是允许用户从相机胶卷中选择一张图片，然后在我的应用程序中存储对该图片的“引用”。然后，我可以在需要时从相机胶卷中加载图像。

我不想复制图像并将其保存在其他地方，因为我觉得这会浪费手机空间。我意识到用户可以从他们的相机胶卷中删除图像，但在这个应用程序的情况下，这并不重要。我将在显示图像之前简单地检查 nil 。它不会影响应用程序的功能。

我可以展示 ImagePickerController，并且很高兴通过以下方式获得 UIImage：

info[UIImagePickerControllerOriginalImage]

我想做的是使用：

info[UIImagePickerControllerReferenceURL]

但是，此功能已被删除，不再受支持。因此，我在寻找 PHAsset 的过程中浪费了几个小时。如果我有要搜索的内容，这对于检索来说似乎很好。我似乎无法编写一个简单的应用程序来通过 UIImagePickerController 获取图像，然后允许我保存引用/URL/uniqueID 等，然后我可以通过其他方法再次使用它们来获取图像。

我很高兴被嘲笑，只要笑的人向我展示了我是多么愚蠢……

非常感谢所有帮助。

Answer 1

我需要以编程方式检查 PHPhotoLibrary.authorizationStatus()，因为应用程序静默失败。将以下内容添加到 AppDelegate.swift 解决了该问题（您需要导入照片）：

func applicationDidBecomeActive(_ application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    photoLibraryAvailabilityCheck()

}

//MARK:- PHOTO LIBRARY ACCESS CHECK
func photoLibraryAvailabilityCheck()
{
    if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.authorized
    {

    }
    else
    {
        PHPhotoLibrary.requestAuthorization(requestAuthorizationHandler)
    }
}
func requestAuthorizationHandler(status: PHAuthorizationStatus)
{
    if PHPhotoLibrary.authorizationStatus() == PHAuthorizationStatus.authorized
    {

    }
    else
    {
        alertToEncouragePhotoLibraryAccessWhenApplicationStarts()
    }
}

//MARK:- CAMERA & GALLERY NOT ALLOWING ACCESS - ALERT
func alertToEncourageCameraAccessWhenApplicationStarts()
{
    //Camera not available - Alert
    let internetUnavailableAlertController = UIAlertController (title: "Camera Unavailable", message: "Please check to see if it is disconnected or in use by another application", preferredStyle: .alert)

    let settingsAction = UIAlertAction(title: "Settings", style: .destructive) { (_) -> Void in
        let settingsUrl = NSURL(string:UIApplicationOpenSettingsURLString)
        if let url = settingsUrl {
            DispatchQueue.main.async {
                UIApplication.shared.open(url as URL, options: [:], completionHandler: nil) //(url as URL)
            }

        }
    }
    let cancelAction = UIAlertAction(title: "Okay", style: .default, handler: nil)
    internetUnavailableAlertController .addAction(settingsAction)
    internetUnavailableAlertController .addAction(cancelAction)
    self.window?.rootViewController!.present(internetUnavailableAlertController , animated: true, completion: nil)
}

func alertToEncouragePhotoLibraryAccessWhenApplicationStarts()
{
    //Photo Library not available - Alert
    let cameraUnavailableAlertController = UIAlertController (title: "Photo Library Unavailable", message: "Please check to see if device settings doesn't allow photo library access", preferredStyle: .alert)

    let settingsAction = UIAlertAction(title: "Settings", style: .destructive) { (_) -> Void in
        let settingsUrl = NSURL(string:UIApplicationOpenSettingsURLString)
        if let url = settingsUrl {
            UIApplication.shared.open(url as URL, options: [:], completionHandler: nil)
        }
    }
    let cancelAction = UIAlertAction(title: "Okay", style: .default, handler: nil)
    cameraUnavailableAlertController .addAction(settingsAction)
    cameraUnavailableAlertController .addAction(cancelAction)
    self.window?.rootViewController!.present(cameraUnavailableAlertController , animated: true, completion: nil)
}