Question

所以我制作了一个社交网络应用，我希望这样做，以便当用户创建新帖子时，在帖子中添加图片是可选的，但标题是必需的。

我正在使用Swift 3和Xcode 8.2.1。我也使用Google Firebase作为我的移动后端即服务（MBAAS）。

以下是我的代码：

import UIKit 
import FirebaseStorage
import Firebase
import FirebaseDatabase

class NewPostViewController: UIViewController {
    @IBOutlet weak var photo: UIImageView!
    @IBOutlet weak var caption: UITextView!
    @IBOutlet weak var postButton: UIButton!

var selectedImage: UIImage?



override func viewDidLoad() {
    super.viewDidLoad()

    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(self.handleSelectPhoto))
    photo.addGestureRecognizer(tapGesture)
    photo.isUserInteractionEnabled = true

}

func handleSelectPhoto() {
    let pickerController = UIImagePickerController()
    pickerController.delegate = self
    present(pickerController, animated: true, completion: nil)
}

@IBAction func postButton(_ sender: Any) {
    ProgressHUD.show("Loading...", interaction: false)
    if let postImage = self.selectedImage, let imageData = UIImageJPEGRepresentation(postImage, 0.1) {
        let photoID = NSUUID().uuidString
        let storageRef = Storage.storage().reference(forURL: "gs://bruh-b7907.appspot.com/").child("post_photos").child(photoID)
        storageRef.putData(imageData, metadata: nil, completion: { (metadata, error) in
            if error != nil {
                ProgressHUD.showError("Could not post")
                return
            }

            let postImageUrl = metadata?.downloadURL()?.absoluteString
            self.sendDataToDatabase(photoUrl: postImageUrl!)

        })
    }

}

func sendDataToDatabase(photoUrl: String) {
    let ref = Database.database().reference()
    let postsReference = ref.child("posts")
    let newPostId = postsReference.childByAutoId().key
    let newPostReference = postsReference.child(newPostId)
    newPostReference.setValue(["postPhotoUrl": photoUrl, "caption": caption.text!], withCompletionBlock: {
        (error,ref) in
        if error != nil {
            ProgressHUD.showError("Could not post")
            return
        }
        ProgressHUD.showSuccess("Successfully Posted")
    })
}

}
extension NewPostViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        if let image = info["UIImagePickerControllerOriginalImage"] as? UIImage{
            selectedImage = image
            photo.image = image
        }
        dismiss(animated: true, completion: nil)
    }
}

Answer 1

添加保护声明以检查您的caption.text

@IBAction func postButton(_ sender: Any) {
    ProgressHUD.show("Loading...", interaction: false)
    if let postImage = self.selectedImage, let imageData = UIImageJPEGRepresentation(postImage, 0.1) {
        let photoID = NSUUID().uuidString
        let storageRef = Storage.storage().reference(forURL: "gs://bruh-b7907.appspot.com/").child("post_photos").child(photoID)
        storageRef.putData(imageData, metadata: nil, completion: { (metadata, error) in
            if error != nil {
                ProgressHUD.showError("Could not post")
                return
            }

            // if there's no any text in your UITextView it'll return
            guard let requiredCaption = caption.text else {
                print("No caption to submit")
                return
            }

            let postImageUrl = metadata?.downloadURL()?.absoluteString
            self.sendDataToDatabase(photoUrl: postImageUrl!)

        })
    }

}

制作应用程序，我想让照片可选，但在制作新帖子时需要标题

1 个答案: