按后退按钮时导航栏消失
UINavigation bar disappears when pressing back button
您可以在表格视图中搜索用户,它会在 UI 导航控制器中显示后退按钮(如图)当我点击一行时,它会将我从表格视图带到个人资料页面 - 但是当我从表格视图中单击返回按钮,顶部的 UI 导航控制器消失,您只能通过滑动返回。我不确定为什么会这样。
Tableview 有一个导航控制器嵌入到页面视图控制器中,该控制器包含 UIView 控制器。
代码 1 显示表格视图,代码 2 显示个人资料页面。
非常感谢任何帮助。
import UIKit
import FirebaseFirestore
import Firebase
class ListOfUsersFromUniversity: UIViewController, UISearchBarDelegate {
@IBOutlet weak var searchBar: UISearchBar!
@IBOutlet weak var tableView: UITableView!
var University:String = ""
var users = [String]()
var filteredUsers = [String]()
var searching = false
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
searchBar.delegate = self
tableView.reloadData()
}
func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
searchBar.becomeFirstResponder()
}
func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
filteredUsers = users.filter({[=10=].lowercased().prefix(searchText.count) == searchText.lowercased()})
searching = true
tableView.reloadData()
}
override func viewWillAppear(_ animated: Bool) {
self.navigationController?.navigationBar.isHidden = false
let docRef = Firestore.firestore().collection("User-Universities").document(University)
docRef.getDocument{ (document, error) in
if let document = document {
let data = document.data()
let keydict = data!.keys
let stringArray = Array(keydict)
print(stringArray)
for user in stringArray {
service.getUsernameFromUID(user) { (username) in
self.users.append(username)
}
}
} else {
print("Document does not exist")
}
}
DispatchQueue.main.async {
self.tableView.reloadData()
}
searchBar.becomeFirstResponder()
}
override func viewWillDisappear(_ animated: Bool) {
users.removeAll()
}
}
extension ListOfUsersFromUniversity: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if searching {
return filteredUsers.count
} else {
return users.count
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell")!
if searching {
cell.textLabel?.text = filteredUsers[indexPath.row]
} else {
cell.textLabel?.text = users[indexPath.row]
}
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let cell = tableView.cellForRow(at: indexPath)!
let username = cell.textLabel!.text ?? ""
let storyboard = UIStoryboard(name: "Search", bundle: nil)
let newVC = storyboard.instantiateViewController(withIdentifier: "ProfilePage") as! ProfileViewController
newVC.username = username
// let navigationController = UINavigationController()
self.navigationController?.pushViewController(newVC, animated: true)
}
}
import UIKit
import FirebaseFirestore
import Firebase
import Kingfisher
class ProfileViewController: UIViewController {
let docRef = Firestore.firestore().collection("users")
var username:String = ""
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.navigationBar.prefersLargeTitles = true
self.title = username
// Do any additional setup after loading the view.
}
override func viewWillAppear(_ animated: Bool) {
self.navigationController?.navigationBar.isHidden = false
}
}
extension ProfileViewController: UICollectionViewDataSource{
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 12
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PostProfileCell", for: indexPath) as! PostCollectionCell
cell.backgroundColor = .red
return cell
}
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
guard kind == UICollectionView.elementKindSectionHeader else {
fatalError("Unexpected element kind.")
}
let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "ProfileHeader", for: indexPath) as! UserProfileHeaderCell
docRef.whereField("username", isEqualTo: username)
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
let data = document.data()
let Link = data["ProfilePicUrl"] as? String ?? ""
let username = data["username"] as? String ?? ""
let university = data["University"] as? String ?? ""
let course = data["Course"] as? String ?? ""
let friends = data["friends"] as? Int
let url = URL(string: Link)
DispatchQueue.main.async {
headerView.University.text = university
headerView.Course.text = course
headerView.Friends.text = String(describing: friends!)
headerView.profilePicture.layer.cornerRadius = headerView.profilePicture.frame.size.width/2
headerView.profilePicture.clipsToBounds = true
let placeholder = UIImage(systemName: "person.circle")
headerView.profilePicture.kf.setImage(with: url, placeholder: placeholder)
}
}
}
}
return headerView
}
override func viewWillDisappear(_ animated: Bool) {
self.navigationController?.navigationBar.isHidden = true
}
}
extension ProfileViewController: UICollectionViewDelegateFlowLayout{
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let columns: CGFloat = 3
let spacing: CGFloat = 1.5
let totalHorizontalSpacing = (columns - 1) * spacing
let itemWidth = (collectionView.bounds.width - totalHorizontalSpacing) / columns
let itemSize = CGSize(width: itemWidth, height: itemWidth)
return itemSize
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 1.5
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 1.5
}
}
您可以使用 viewWillAppear
将其设置为可见。
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.setNavigationBarHidden(false, animated: true)
}
您可以在表格视图中搜索用户,它会在 UI 导航控制器中显示后退按钮(如图)当我点击一行时,它会将我从表格视图带到个人资料页面 - 但是当我从表格视图中单击返回按钮,顶部的 UI 导航控制器消失,您只能通过滑动返回。我不确定为什么会这样。
Tableview 有一个导航控制器嵌入到页面视图控制器中,该控制器包含 UIView 控制器。
代码 1 显示表格视图,代码 2 显示个人资料页面。 非常感谢任何帮助。
import UIKit
import FirebaseFirestore
import Firebase
class ListOfUsersFromUniversity: UIViewController, UISearchBarDelegate {
@IBOutlet weak var searchBar: UISearchBar!
@IBOutlet weak var tableView: UITableView!
var University:String = ""
var users = [String]()
var filteredUsers = [String]()
var searching = false
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
searchBar.delegate = self
tableView.reloadData()
}
func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
searchBar.becomeFirstResponder()
}
func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
filteredUsers = users.filter({[=10=].lowercased().prefix(searchText.count) == searchText.lowercased()})
searching = true
tableView.reloadData()
}
override func viewWillAppear(_ animated: Bool) {
self.navigationController?.navigationBar.isHidden = false
let docRef = Firestore.firestore().collection("User-Universities").document(University)
docRef.getDocument{ (document, error) in
if let document = document {
let data = document.data()
let keydict = data!.keys
let stringArray = Array(keydict)
print(stringArray)
for user in stringArray {
service.getUsernameFromUID(user) { (username) in
self.users.append(username)
}
}
} else {
print("Document does not exist")
}
}
DispatchQueue.main.async {
self.tableView.reloadData()
}
searchBar.becomeFirstResponder()
}
override func viewWillDisappear(_ animated: Bool) {
users.removeAll()
}
}
extension ListOfUsersFromUniversity: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if searching {
return filteredUsers.count
} else {
return users.count
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell")!
if searching {
cell.textLabel?.text = filteredUsers[indexPath.row]
} else {
cell.textLabel?.text = users[indexPath.row]
}
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let cell = tableView.cellForRow(at: indexPath)!
let username = cell.textLabel!.text ?? ""
let storyboard = UIStoryboard(name: "Search", bundle: nil)
let newVC = storyboard.instantiateViewController(withIdentifier: "ProfilePage") as! ProfileViewController
newVC.username = username
// let navigationController = UINavigationController()
self.navigationController?.pushViewController(newVC, animated: true)
}
}
import UIKit
import FirebaseFirestore
import Firebase
import Kingfisher
class ProfileViewController: UIViewController {
let docRef = Firestore.firestore().collection("users")
var username:String = ""
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.navigationBar.prefersLargeTitles = true
self.title = username
// Do any additional setup after loading the view.
}
override func viewWillAppear(_ animated: Bool) {
self.navigationController?.navigationBar.isHidden = false
}
}
extension ProfileViewController: UICollectionViewDataSource{
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 12
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PostProfileCell", for: indexPath) as! PostCollectionCell
cell.backgroundColor = .red
return cell
}
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
guard kind == UICollectionView.elementKindSectionHeader else {
fatalError("Unexpected element kind.")
}
let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "ProfileHeader", for: indexPath) as! UserProfileHeaderCell
docRef.whereField("username", isEqualTo: username)
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
let data = document.data()
let Link = data["ProfilePicUrl"] as? String ?? ""
let username = data["username"] as? String ?? ""
let university = data["University"] as? String ?? ""
let course = data["Course"] as? String ?? ""
let friends = data["friends"] as? Int
let url = URL(string: Link)
DispatchQueue.main.async {
headerView.University.text = university
headerView.Course.text = course
headerView.Friends.text = String(describing: friends!)
headerView.profilePicture.layer.cornerRadius = headerView.profilePicture.frame.size.width/2
headerView.profilePicture.clipsToBounds = true
let placeholder = UIImage(systemName: "person.circle")
headerView.profilePicture.kf.setImage(with: url, placeholder: placeholder)
}
}
}
}
return headerView
}
override func viewWillDisappear(_ animated: Bool) {
self.navigationController?.navigationBar.isHidden = true
}
}
extension ProfileViewController: UICollectionViewDelegateFlowLayout{
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let columns: CGFloat = 3
let spacing: CGFloat = 1.5
let totalHorizontalSpacing = (columns - 1) * spacing
let itemWidth = (collectionView.bounds.width - totalHorizontalSpacing) / columns
let itemSize = CGSize(width: itemWidth, height: itemWidth)
return itemSize
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 1.5
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 1.5
}
}
您可以使用 viewWillAppear
将其设置为可见。
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.setNavigationBarHidden(false, animated: true)
}