所以我有一个如下图所示的 firebase 结构 
现在我想检索我上传的那个图像文件。解码 base64String 并显示它。每个用户都可以发帖，发送到 firebase 的信息有描述等，也有图片。现在我尝试使用此代码检索它，但没有任何效果。
var REF_LIST = Firebase(url: "\(URL_BASE)/listItems")
REF_LIST.observeEventType(FEventType.Value, withBlock: { snapshot in
let image = snapshot.value.objectForKey("images") as! String
但这已经在该行上给了我一个零错误，所以我什至无法解码。我想我明白为什么它给我一个零错误，在 firebase 的 listItems 中没有图像，你首先有唯一的 ID，然后是带有图像的规范。现在我不知道如何从那个唯一的检索信息身份证？
更新: tableViewController 将从 firebase 接收数据:
import UIKit
import FBSDKLoginKit
import Alamofire
import Firebase
class ListVC: UIViewController, UITableViewDataSource, UITableViewDelegate {
@IBOutlet weak var tableView: UITableView!
var lists = [List]()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
dispatch_async(backgroundQueue, {
self.initObservers()
})
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
self.tableView.reloadData()
}
func initObservers() {
LoadingOverlay.shared.showOverlay(self.view)
DataService.ds.REF_LISTS.observeEventType(.Value, withBlock: { snapshot in
print(snapshot.value)
self.lists = []
if let snapshots = snapshot.children.allObjects as? [FDataSnapshot] {
for snap in snapshots {
print("SNAP: \(snap)")
if let listDict = snap.value as? Dictionary<String, AnyObject> {
let key = snap.key
let list = List(listKey: key, dictionary: listDict)
self.lists.insert(list, atIndex:0)
}
}
}
self.tableView.reloadData()
LoadingOverlay.shared.hideOverlayView()
})
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return lists.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
if let cell = tableView.dequeueReusableCellWithIdentifier("ListCell") as? ListCell {
let list = self.lists[indexPath.row]
cell.request?.cancel()
cell.configureCell(list)
return cell
} else {
return ListCell()
}
}
}
将数据发布到 firebase 的 addController:
import UIKit
import Firebase
import Alamofire
import FBSDKCoreKit
class AddVC: UIViewController, UITextFieldDelegate, UITextViewDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
@IBOutlet weak var addTitle: UITextField!
@IBOutlet weak var addDescription: UITextView!
@IBOutlet weak var addLocation: UITextField!
@IBOutlet weak var placeholderLbl: UILabel!
@IBOutlet weak var freeSwitch: UISwitch!
@IBOutlet weak var tradeSwitch: UISwitch!
@IBOutlet weak var imageSelectorImg: UIImageView!
@IBOutlet weak var overlayView: UIView!
var currentUsername = ""
var imageSelected = false
var imagePicker: UIImagePickerController!
var base64String: NSString = ""
override func viewDidLoad() {
super.viewDidLoad()
addTitle.delegate = self
addDescription.delegate = self
addLocation.delegate = self
imagePicker = UIImagePickerController()
imagePicker.delegate = self
getCurrentUser()
hideKeyboardWhenTappedAround()
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
addTitle.text = ""
addDescription.text = ""
addLocation.text = ""
freeSwitch.setOn(false, animated: false)
tradeSwitch.setOn(false, animated: false)
placeholderLbl.hidden = false
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func getCurrentUser() {
DataService.ds.REF_USER_CURRENT.observeEventType(FEventType.Value, withBlock: { snapshot in
let currentUser = snapshot.value.objectForKey("username") as! String
print("Username: \(currentUser)")
self.currentUsername = currentUser }, withCancelBlock: { error in
print(error.description)
})
}
func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage, editingInfo: [String : AnyObject]?) {
imagePicker.dismissViewControllerAnimated(true, completion: nil)
imageSelectorImg.image = image
dispatch_async(backgroundQueue, {
let uploadImage = image
let imageData = UIImageJPEGRepresentation(uploadImage, 0.5)
self.base64String = imageData!.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding64CharacterLineLength)
})
imageSelected = true
}
@IBAction func selectImage(sender: UITapGestureRecognizer) {
presentViewController(imagePicker, animated: true, completion: nil)
}
func postToFirebase() {
// LoadingOverlay.shared.showOverlay(self.overlayView)
var post: Dictionary<String, AnyObject> = ["username": self.currentUsername, "description": self.addDescription.text!, "title": self.addTitle.text!, "location": self.addLocation.text!, "images": self.base64String]
if self.freeSwitch.on && self.tradeSwitch.on {
post["tradeOption"] = "Gratis/Te ruil"
} else if self.freeSwitch.on {
post["tradeOption"] = "Gratis"
} else if self.tradeSwitch.on {
post["tradeOption"] = "Te ruil"
}
let firebasePost = DataService.ds.REF_LISTS.childByAutoId()
firebasePost.setValue(post)
}
@IBAction func postListItem(sender: AnyObject) {
if let addTitle = addTitle.text where addTitle != "", let addDescription = addDescription.text where addDescription != "", let addLocation = addLocation.text where addLocation != "" {
dispatch_async(backgroundQueue, {
self.postToFirebase()
dispatch_async(dispatch_get_main_queue(), { () -> Void in
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let listVC = storyboard.instantiateViewControllerWithIdentifier("TBC") as! UITabBarController
listVC.selectedIndex = 1
self.presentViewController(listVC, animated: false, completion: nil)
})
})
}
}
func textViewDidBeginEditing(textView: UITextView) {
placeholderLbl.hidden = true
}
func textViewDidEndEditing(textView: UITextView) {
if textView.text == "" {
placeholderLbl.hidden = false
}
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
}
和用于配置单元格的 swift 文件:
import UIKit
import Alamofire
import Firebase
class ListCell: UITableViewCell {
@IBOutlet weak var listImg: UIImageView!
@IBOutlet weak var listTitle: UILabel!
@IBOutlet weak var listTradeOption: UILabel!
@IBOutlet weak var listLocation: UILabel!
@IBOutlet weak var headImg: UIImageView!
var list: List!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
func retrieveImages() {
DataService.ds.REF_LISTS.observeEventType(FEventType.Value, withBlock: { snapshot in
if let snapshots = snapshot.children.allObjects as? [FDataSnapshot] {
for snap in snapshots {
let image = snap.value.objectForKey("images") as! String
let decodedData = NSData(base64EncodedString: image, options: NSDataBase64DecodingOptions.IgnoreUnknownCharacters)
let decodedImage = UIImage(data: decodedData!)
self.headImg.image = decodedImage
}
}
})
}
func configureCell(list: List) {
self.list = list
self.listTitle.text = list.listTitle
self.listTradeOption.text = list.listTradeOption
self.listLocation.text = list.listLocation
retrieveImages()
}
还有列表模型文件:
import Foundation
import Firebase
class List {
private var _listTitle: String!
private var _listDescription: String!
private var _listTradeOption: String!
private var _listLocation: String!
private var _listImageURL: String?
private var _listKey: String!
private var _listRef: Firebase!
var listTitle: String? {
return _listTitle
}
var listDescription: String? {
return _listDescription
}
var listTradeOption: String? {
return _listTradeOption
}
var listLocation: String? {
return _listLocation
}
var listKey: String {
return _listKey
}
var listImageURL: String? {
return _listImageURL
}
init(title: String, description: String, tradeOption: String, location: String, listImageURL: String?) {
self._listTitle = title
self._listDescription = description
self._listTradeOption = tradeOption
self._listLocation = location
self._listImageURL = listImageURL
}
init(listKey: String, dictionary: Dictionary<String, AnyObject>) {
self._listKey = listKey
if let title = dictionary ["title"] as? String {
self._listTitle = title
}
if let desc = dictionary ["description"] as? String {
self._listDescription = desc
}
if let trade = dictionary ["tradeOption"] as? String {
self._listTradeOption = trade
}
if let loc = dictionary ["location"] as? String {
self._listLocation = loc
}
if let imgUrl = dictionary["images"] as? String {
self._listImageURL = imgUrl
}
self._listRef = DataService.ds.REF_LISTS.childByAppendingPath(self._listKey)
}
}
我还有一个数据服务文件，我在其中使用以下代码通过唯一 ID 创建用户:
var REF_USER_CURRENT: Firebase {
let uid = NSUserDefaults.standardUserDefaults().valueForKey(KEY_UID) as! String
let user = Firebase(url: "\(REF_BASE)").childByAppendingPath("users").childByAppendingPath(uid)
return user!
}
func createFirebaseUser(uid: String, user: Dictionary<String, String>) {
REF_USERS.childByAppendingPath(uid).setValue(user)
}
我知道很多，但也许是最好的帮助方式:)
最佳答案
尝试在列表单元格中编辑它
var imageURL = String()
func retrieveImages() {
let decodedData = NSData(base64EncodedString: imageURL, options: NSDataBase64DecodingOptions.IgnoreUnknownCharacters)
let decodedImage = UIImage(data: decodedData!)
self.headImg.image = decodedImage
}
func configureCell(list: List) {
self.list = list
self.listTitle.text = list.listTitle
self.listTradeOption.text = list.listTradeOption
self.listLocation.text = list.listLocation
self.imageURL = list.listImageURL //you already had the image url for that specific cell
retrieveImages()
}
关于swift - 从 firebase 检索图像？ ( swift )，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/37056068/