[英]Pass Firebase data from UITableViewCell to ViewController
[英](iOS + Firebase) Unable to pass the Image to the next ViewController from a UITableViewCell
我有一個UITableView
,其中的數據來自Firebase RealtimeDatabase。 一旦用戶選擇了該行,該行中的數據即標題,描述和圖像將被帶到下一個ViewController。
我可以通過標題和說明,但不能通過圖像。
這是我的UITableView代碼:
import UIKit
import Firebase
class PostTable: UIViewController, UITableViewDelegate, UITableViewDataSource {
var tableView:UITableView!
var posts = [Post]()
override func viewDidLoad() {
super.viewDidLoad()
tableView = UITableView(frame: view.bounds, style: .plain)
view.addSubview(tableView)
let cellNib = UINib(nibName: "PostTableViewCell", bundle: nil)
tableView.register(cellNib, forCellReuseIdentifier: "postCell")
var layoutGuide:UILayoutGuide!
layoutGuide = view.safeAreaLayoutGuide
tableView.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor).isActive = true
tableView.topAnchor.constraint(equalTo: layoutGuide.topAnchor).isActive = true
tableView.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor).isActive = true
tableView.bottomAnchor.constraint(equalTo: layoutGuide.bottomAnchor).isActive = true
tableView.delegate = self
tableView.dataSource = self
tableView.tableFooterView = UIView()
tableView.reloadData()
observePosts()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func observePosts() {
let postsRef = Database.database().reference().child("Data")
print(postsRef)
postsRef.observe(.value, with: { snapshot in
var tempPosts = [Post]()
for child in snapshot.children{
if let childSnapshot = child as? DataSnapshot,
let dict = childSnapshot.value as? [String:Any],
let title = dict["title"] as? String,
let logoImage = dict["image"] as? String,
let url = URL(string:logoImage),
let description = dict["description"] as? String{
let userProfile = UserProfile(title: title, photoURL: url)
let post = Post(id: childSnapshot.key, title: userProfile, description: description, image: userProfile)
print(post)
tempPosts.append(post)
}
}
self.posts = tempPosts
self.tableView.reloadData()
})
}
func getImage(url: String, completion: @escaping (UIImage?) -> ()) {
URLSession.shared.dataTask(with: URL(string: url)!) { data, response, error in
if error == nil {
completion(UIImage(data: data!))
} else {
completion(nil)
}
}.resume()
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print(posts.count)
return posts.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
let cell = tableView.dequeueReusableCell(withIdentifier: "postCell", for: indexPath) as! PostTableViewCell
cell.set(post: posts[indexPath.row])
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let postsInfo = posts[indexPath.row]
print(postsInfo)
let Storyboard = UIStoryboard(name: "Main", bundle: nil)
let DvC = Storyboard.instantiateViewController(withIdentifier: "PostTableDetailed") as! PostTableDetailed
DvC.getName = postsInfo.title.title
DvC.getDesc = postsInfo.description
// DvC.getImg = postsInfo.title.photoURL
self.navigationController?.pushViewController(DvC, animated: true)
}
}
這是第二個具有帖子詳細信息的ViewControler:
import UIKit
class PostTableDetailed: UIViewController {
var getName = String()
var getDesc = String()
@IBOutlet weak var Name: UILabel!
@IBOutlet weak var Description: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
Name.text! = getName
Description.text! = getDesc
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
我也有一些模型(Post,UserProfile)和服務(UserService和ImageService),請告訴我是否可以解決此問題。
如果您有imageUrl,則只需將其從PostTable傳遞到PostTableDetailed並下載圖像。
// PostTable
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let postsInfo = posts[indexPath.row]
print(postsInfo)
let Storyboard = UIStoryboard(name: "Main", bundle: nil)
let DvC = Storyboard.instantiateViewController(withIdentifier: "PostTableDetailed") as! PostTableDetailed
DvC.getName = postsInfo.title.title
DvC.getDesc = postsInfo.description
DvC.getImg = postsInfo.photoURL
self.navigationController?.pushViewController(DvC, animated: true)
}
// PostTableDetailed
class PostTableDetailed: UIViewController {
var getName = String()
var getDesc = String()
var imageUrl = ""
@IBOutlet weak var Name: UILabel!
@IBOutlet weak var Description: UILabel!
@IBOutlet weak var imageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
Name.text! = getName
Description.text! = getDesc
updayeImage()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
private func updateImage() {
URLSession.shared.dataTask(with: URL(string: self.imageUrl)!) { data, response, error in
if error == nil, let data = data {
imageView.image = UIImage(data: data)
}
}.resume()
}
}
任務完成時將顯示該圖像。 因此,我建議您將微調器添加到imageView。
在PostDetail ViewController中這樣做
import UIKit
class PostTableDetailed: UIViewController {
var getName = String()
var getDesc = String()
var getImg = String()
@IBOutlet weak var Name: UILabel!
@IBOutlet weak var Description: UILabel!
@IBOutlet weak var ImageContainer: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
Name.text! = getName
Description.text! = getDesc
if let image = getImage(url: getImg) { (image)
ImageContainer.image = image
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func getImage(url: String, completion: @escaping (UIImage?) -> ()) {
URLSession.shared.dataTask(with: URL(string: url)!) { data, response, error in
if error == nil {
completion(UIImage(data: data!))
} else {
completion(nil)
}
}.resume()
}
}
首先,您可以使用以下代碼下載圖像:
let imageCache = NSCache<AnyObject, AnyObject>()
extension UIImageView {
func downloadImageWithUrlString(urlString: String) -> Void {
if urlString.count == 0 {
print("Image Url is not found")
return
}
self.image = nil
if let cachedImage = imageCache.object(forKey: urlString as AnyObject) as? UIImage {
self.image = cachedImage
return
}
let request = URLRequest(url: URL(string: urlString)!)
let dataTask = URLSession.shared.dataTask(with: request) {data, response, error in
if error != nil { return }
DispatchQueue.main.async {
let downloadedImage = UIImage(data: data!)
if let image = downloadedImage {
imageCache.setObject(image, forKey: urlString as AnyObject)
self.image = UIImage(data: data!)
}
}
}
dataTask.resume()
}
}
現在,如果您使用的模型包含Title,Description和ImageUrlString,則只需將所選模型對象傳遞給下一個viewController。
在下一個ViewController中,只需調用相同的方法來下載您在第一個ViewController上使用的圖像。 您無需將映像從VC1傳遞到VC2,因為它可能尚未下載映像,並且您選擇了要在下一個VC上移動的行。
因此,這里傳遞模型對象並調用圖像下載方法的簡單操作。
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