Swift4中使用UIImagePickerController传递图片数据问题求助

Hey there! Let's get that image passing working properly. From what you've shared, you've got the tab bar triggering the camera, but you're missing the delegate methods to handle the selected image and pass it along. Here's how to fix it step by step:

1. Make Sure Your CameraViewController Follows Required Protocols #

First, update your CameraViewController class declaration to conform to the UIImagePickerControllerDelegate and UINavigationControllerDelegate protocols. These are needed to receive callbacks when an image is selected or the picker is canceled:

class CameraViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    // Your existing code here
}

2. Correctly Initialize & Present the UIImagePickerController #

Update your tab bar delegate method to properly set up the image picker and link its delegate to your CameraViewController. Instead of relying solely on the tab index (which can break if you reorder tabs), check if the selected view controller is an instance of CameraViewController:

func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
    guard let cameraVC = viewController as? CameraViewController else { return }
    
    let imagePicker = UIImagePickerController()
    imagePicker.sourceType = .camera // Use .photoLibrary if you want to pick from gallery too
    imagePicker.delegate = cameraVC // Link the picker to your camera VC's delegates
    tabBarController.present(imagePicker, animated: true, completion: nil)
}

Don't forget to add camera permission descriptions in your Info.plist (add NSCameraUsageDescription with a clear reason why your app needs camera access) — otherwise the camera won't open!

3. Implement Delegate Methods to Handle Selected Image #

Add these methods inside your CameraViewController to capture the selected image and pass it to your next view controller:

// Triggered when user selects an image
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
    // Extract the original image from the info dictionary
    guard let selectedImage = info[.originalImage] as? UIImage else {
        picker.dismiss(animated: true, completion: nil)
        return
    }
    
    // Dismiss the picker first, then navigate to the next VC
    picker.dismiss(animated: true) {
        // Replace `NextViewController` with your actual destination VC class
        let destinationVC = NextViewController()
        // Assume your destination VC has a property to hold the image (e.g., `selectedImage`)
        destinationVC.selectedImage = selectedImage
        
        // Navigate — use push if your CameraVC is in a UINavigationController, else present
        if let navController = self.navigationController {
            navController.pushViewController(destinationVC, animated: true)
        } else {
            self.present(destinationVC, animated: true, completion: nil)
        }
    }
}

// Triggered when user cancels the picker
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
    picker.dismiss(animated: true, completion: nil)
}

4. Prepare Your Destination View Controller #

Make sure your next view controller has a property to receive the image:

class NextViewController: UIViewController {
    // Add this property to hold the passed image
    var selectedImage: UIImage?
    
    // You can then use this image in viewDidLoad, e.g., set it to an UIImageView
    override func viewDidLoad() {
        super.viewDidLoad()
        if let image = selectedImage {
            yourImageView.image = image
        }
    }
}

That should do it! Now when you select an image from the camera, it'll be passed to your next view controller successfully.

内容的提问来源于stack exchange，提问作者Gorib Developer