我正在使用Firebase制作iPhone应用,我遇到以下代码的小问题。
import UIKit
import Firebase
class ChatController: UICollectionViewController, UITextFieldDelegate, UICollectionViewDelegateFlowLayout {
var game: Game? {
didSet {
navigationItem.title = game?.name
}
}
lazy var inputTextField: UITextField = {
let textField = UITextField()
textField.placeholder = "Enter message..."
textField.translatesAutoresizingMaskIntoConstraints = false
return textField
}()
let cellId = "cellId"
override func viewDidLoad() {
super.viewDidLoad()
collectionView?.alwaysBounceVertical = true
collectionView?.backgroundColor = UIColor.white
collectionView?.register(ChatMessageCell.self, forCellWithReuseIdentifier: cellId)
setupInputComponents()
}
var messages = [Message]()
func observeMessages() {
let ref = Database.database().reference().child("games").child((game?.id)!).child("messages")
ref.observe(.childAdded, with: { (snapshot) in
if let dictionary = snapshot.value as? [String: AnyObject] {
let message = Message()
message.setValuesForKeys(dictionary)
self.messages.append(message)
DispatchQueue.main.async {
self.collectionView?.reloadData()
}
}
}, withCancel: nil)
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return messages.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath as IndexPath) as! ChatMessageCell
// let message = messages[indexPath.item]
// cell.textView.text = message.text
cell.backgroundColor = UIColor.blue
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: NSIndexPath) -> CGSize {
return CGSize(width: view.frame.width, height: 80)
}
// Sets up the entire message sending
// container for the send button and input
// text field
func setupInputComponents() {
// Creates the container for send button
// and input text field
let containerView = UIView()
containerView.backgroundColor = UIColor.white
containerView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(containerView)
// anchor constraints and x,y,w,h
// for positioning the container
containerView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
containerView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
containerView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
containerView.heightAnchor.constraint(equalToConstant: 50).isActive = true
// Creates the send button
let sendButton = UIButton(type: .system)
sendButton.setTitle("Send", for: .normal)
sendButton.translatesAutoresizingMaskIntoConstraints = false
sendButton.addTarget(self, action: #selector(handleSend), for: .touchUpInside)
containerView.addSubview(sendButton)
// Positions the send button within the container
sendButton.rightAnchor.constraint(equalTo: containerView.rightAnchor).isActive = true
sendButton.centerYAnchor.constraint(equalTo: containerView.centerYAnchor).isActive = true
sendButton.widthAnchor.constraint(equalToConstant: 80).isActive = true
sendButton.heightAnchor.constraint(equalTo: containerView.heightAnchor).isActive = true
// Creates the input text field
containerView.addSubview(inputTextField)
// Positions the send button within the container
inputTextField.leftAnchor.constraint(equalTo: containerView.leftAnchor, constant: 8).isActive = true
inputTextField.centerYAnchor.constraint(equalTo: containerView.centerYAnchor).isActive = true
inputTextField.rightAnchor.constraint(equalTo: sendButton.leftAnchor).isActive = true
inputTextField.heightAnchor.constraint(equalTo: containerView.heightAnchor).isActive = true
// Create a seperator for this component
let seperatorLineView = UIView()
seperatorLineView.backgroundColor = UIColor(r: 220, g: 220, b: 220)
seperatorLineView.translatesAutoresizingMaskIntoConstraints = false
containerView.addSubview(seperatorLineView)
// Positions the seperator
seperatorLineView.leftAnchor.constraint(equalTo: containerView.leftAnchor, constant: 8).isActive = true
seperatorLineView.widthAnchor.constraint(equalTo: containerView.widthAnchor).isActive = true
seperatorLineView.topAnchor.constraint(equalTo: containerView.topAnchor).isActive = true
seperatorLineView.heightAnchor.constraint(equalToConstant: 1).isActive = true
}
override var preferredStatusBarStyle: UIStatusBarStyle {
return .lightContent
}
@objc func handleSend() {
let ref = Database.database().reference().child("games").child("-L6lIJt_cw6saNNWMgu1").child("messages")
ref.keepSynced(true)
let childRef = ref.childByAutoId()
let values = ["text": inputTextField.text!]
childRef.updateChildValues(values)
}
}
我有一些注释掉的部分实际上是我想要在我的单元格中显示为文本但我甚至无法在CollectionViewController中为我显示彩色框。数据库检索代码工作得很好,我可以在TableViewController中显示它给我的内容。它不在我在这里制作的CollectionViewController中。
正是发生了什么,应用程序构建和加载成功,但当我导航到此屏幕时,我正在创建的单元格没有显示。这些行具体如下:
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return messages.count
// return 5
}
override func collectionView(_ collectionView: UICollectionView,, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath as IndexPath) as! ChatMessageCell
// let message = messages[indexPath.item]
// cell.textView.text = message.text
cell.backgroundColor = UIColor.blue
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: NSIndexPath) -> CGSize {
return CGSize(width: view.frame.width, height: 80)
}
答案 0 :(得分:1)
您需要添加以下代理和数据源。
向您的班级添加UICollectionViewDataSource
和UICollectionViewDelegate
。
然后在viewDidLoad
添加self.collectionView?.delegate = self
和self.collectionView?.dataSource = self
。
这告诉视图控制器它的委托和数据源方法在它自己的类中。 这应该可以解决您的问题。很抱歉,如果此答案中的格式有点偏差。在我的手机上,所以在输入答案时看不到问题!