我有一个应用程序，它使用一个水平滚动的集合视图，并在其中包含collectionviewcells。一切都很顺利，直到我尝试使用textfielddelegate实现一个包含2个文本字段的登录/注册单元格。当我按下其中一个文本字段时，键盘会显示一瞬间然后隐藏。在它执行此操作之后，视图被按下一点点，如果我再次按下文本字段，它会被向上推，不会下降。以下是一些截图：
before touching a textfield与after I touch a textfield
我收到各种UICollectionViewFlowLayout错误，要求我在UICollectionViewFlowLayoutBreakForInvalidSizes处创建符号断点。
The behavior of the UICollectionViewFlowLayout is not defined because:
2017-04-26 13:55:03.199199-0400 Eyetube[1500:243622] the item height must be less than the height of the UICollectionView minus the section insets top and bottom values, minus the content insets top and bottom values.
2017-04-26 13:55:03.200490-0400 Eyetube[1500:243622] The relevant UICollectionViewFlowLayout instance is <UICollectionViewFlowLayout: 0x10453ee90>, and it is attached to <UICollectionView: 0x104806800; frame = (0 0; 768 960); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0x17405a610>; layer = <CALayer: 0x17002f0a0>; contentOffset: {2304, 0}; contentSize: {3072, 910}> collection view layout: <UICollectionViewFlowLayout: 0x10453ee90>.
2017-04-26 13:55:03.200575-0400 Eyetube[1500:243622] Make a symbolic breakpoint at UICollectionViewFlowLayoutBreakForInvalidSizes to catch this in the debugger.
我尝试过多次调试，但是找不到错误的确切位置并没有太大帮助。我已经被困在这个问题上好几个小时了，似乎无法解决这个问题。
我在collectionviewcontroller中初始化布局的地方：
func setupCollectionView() {
if let flowLayout = collectionView?.collectionViewLayout as? UICollectionViewFlowLayout {
flowLayout.scrollDirection = .horizontal
flowLayout.minimumLineSpacing = 0
}
collectionView?.backgroundColor = UIColor.white
collectionView?.register(VideoFeedCell.self, forCellWithReuseIdentifier: cellId)
collectionView?.register(ChannelFeedCell.self, forCellWithReuseIdentifier: channelCellId)
collectionView?.register(ARFeedCell.self, forCellWithReuseIdentifier: augmentedRealityCellId)
collectionView?.register(LoginRegisterCell.self, forCellWithReuseIdentifier: loginRegisterCellId)
collectionView?.contentInset = UIEdgeInsetsMake(0, 0, 50, 0)
collectionView?.scrollIndicatorInsets = UIEdgeInsetsMake(0, 0, 50, 0)
collectionView?.isPagingEnabled = true
}
我的sizeForItemAt func，也在我的collectionviewcontroller中（PS，我从高处减去50，因为我添加了作为视图的子视图的底部菜单栏。我也因为这个而更改了collectionview的contentInset和scrollIndicatorInsets）：< / p>
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let cellSize = CGSize(width: view.frame.width, height: view.frame.height - 50)
return cellSize
}
以下是collectionviewcell的完整代码，我遇到了问题：
import UIKit
class LoginRegisterCell：BaseCell，UITextFieldDelegate {
let logoImageView: UIImageView = {
let imageView = UIImageView()
imageView.image = UIImage(named: "eyetube_logo_font")
imageView.translatesAutoresizingMaskIntoConstraints = false
imageView.contentMode = .scaleAspectFit
return imageView
}()
let emailTextField: LeftPaddedTextField = {
let tf = LeftPaddedTextField()
tf.keyboardType = .emailAddress
tf.placeholder = "Enter email"
tf.substituteFontName = "SourceSansPro-Regular"
tf.layer.borderColor = UIColor.rgb(220, green: 220, blue: 220).cgColor
tf.layer.borderWidth = 1
tf.translatesAutoresizingMaskIntoConstraints = false
return tf
}()
let passwordTextField: LeftPaddedTextField = {
let tf = LeftPaddedTextField()
tf.placeholder = "Enter password"
tf.substituteFontName = "SourceSansPro-Regular"
tf.layer.borderColor = UIColor.rgb(220, green: 220, blue: 220).cgColor
tf.layer.borderWidth = 1
tf.isSecureTextEntry = true
tf.translatesAutoresizingMaskIntoConstraints = false
return tf
}()
lazy var loginButton: UIButton = {
let button = UIButton(type: .system)
button.backgroundColor = UIColor.rgb(225, green: 31, blue: 40)
button.titleLabel?.font = UIFont(name: "SourceSansPro-SemiBold", size: 20)
button.setTitle("Log In", for: .normal)
button.setTitleColor(UIColor.white, for: .normal)
button.translatesAutoresizingMaskIntoConstraints = false
button.addTarget(self, action: #selector(handleLogin), for: .touchUpInside)
return button
}()
lazy var registerLink: UIButton = {
let button = UIButton(type: .system)
button.setTitle("Don't have an account? Register here", for: .normal)
button.translatesAutoresizingMaskIntoConstraints = false
button.titleLabel?.font = UIFont(name: "SourceSansPro-Regular", size: 18)
button.setTitleColor(UIColor.darkGray, for: .normal)
let underlineAttribute = [NSUnderlineStyleAttributeName: NSUnderlineStyle.styleSingle.rawValue]
let underlineAttributedString = NSAttributedString(string: (button.titleLabel?.text)!, attributes: underlineAttribute)
button.titleLabel?.attributedText = underlineAttributedString
button.addTarget(self, action: #selector(handleRegister), for: .touchUpInside)
return button
}()
var containerView: UIView!
override func setupViews() {
super.setupViews()
self.emailTextField.delegate = self
emailTextField.returnKeyType = .next
self.passwordTextField.delegate = self
passwordTextField.returnKeyType = .done
containerView = UIView(frame: CGRect(x: 0, y: 0, width: self.frame.width, height: self.frame.height))
containerView.backgroundColor = .green
addSubview(containerView)
containerView.addSubview(logoImageView)
containerView.addSubview(emailTextField)
containerView.addSubview(passwordTextField)
containerView.addSubview(loginButton)
containerView.addSubview(registerLink)
setupLogoImageView()
setupInputs()
setupLoginButton()
setupRegisterLink()
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
func handleLogin() {
//first check if the email/password textfields are empty or not
guard let email = emailTextField.text , !email.isEmpty else {
let alert = UIAlertView (title: "Invalid Email", message: "Please enter an email to log in", delegate: self, cancelButtonTitle: "OK")
alert.show()
return
}
guard let password = passwordTextField.text , !password.isEmpty else {
let alert = UIAlertView (title: "Invalid Password", message: "Please enter a password to log in", delegate: self, cancelButtonTitle: "OK")
alert.show()
return
}
//create session here
ApiLoginAuthentication.sharedInstance.login_now(username: email, password: password, onCompletion: {(loginSuccessful: Bool) -> Void in
guard (loginSuccessful) else {
DispatchQueue.main.async {
let alert = UIAlertView (title: "Invalid Account info", message: "The account information entered is invalid. Please log in with a valid account.", delegate: self, cancelButtonTitle: "OK")
alert.show()
}
return
}
DispatchQueue.main.async {
self.emailTextField.text = ""
self.passwordTextField.text = ""
}
print("the login was successful")
})
/**
let profileUrl: String = "https://eyetube.net/user/profile.asp"
ApiLoginAuthentication.sharedInstance.getContent(contentUrl: profileUrl, onCompletion: {(responseString: String, isLoggedIn: Bool) -> Void in
print(responseString)
print("user status: \(isLoggedIn)")
let json: Any?
do {
let data: NSData = responseString.data(using: String.Encoding.utf8)! as NSData
json = try JSONSerialization.jsonObject(with: data as Data, options: .allowFragments)
print(json)
} catch let error {
print("error: \(error)")
}
})**/
}
func handleRegister() {
let eyetubeRegisterLink = "https://eyetube.net/user/register.asp?rUrl="
UIApplication.shared.openURL(URL(string: eyetubeRegisterLink)!)
}
func setupLogoImageView() {
var sizeConstant: CGFloat!
var centerYConstant: CGFloat!
if UI_USER_INTERFACE_IDIOM() == .pad {
sizeConstant = 400
centerYConstant = -260
} else {
sizeConstant = 200
centerYConstant = -160
}
NSLayoutConstraint(item: logoImageView, attribute: .centerY, relatedBy: .equal, toItem: containerView, attribute: .centerY, multiplier: 1, constant: centerYConstant!).isActive = true
NSLayoutConstraint(item: logoImageView, attribute: .centerX, relatedBy: .equal, toItem: containerView, attribute: .centerX, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: logoImageView, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .width, multiplier: 1, constant: sizeConstant).isActive = true
NSLayoutConstraint(item: logoImageView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1, constant: sizeConstant).isActive = true
}
func setupInputs() {
var widthConstant: CGFloat!
var leftConstant: CGFloat!
if UI_USER_INTERFACE_IDIOM() == .pad {
widthConstant = -64
leftConstant = 32
} else {
widthConstant = -32
leftConstant = 16
}
NSLayoutConstraint(item: emailTextField, attribute: .top, relatedBy: .equal, toItem: logoImageView, attribute: .bottom, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: emailTextField, attribute: .left, relatedBy: .equal, toItem: containerView, attribute: .left, multiplier: 1, constant: leftConstant).isActive = true
NSLayoutConstraint(item: emailTextField, attribute: .width, relatedBy: .equal, toItem: containerView, attribute: .width, multiplier: 1, constant: widthConstant).isActive = true
NSLayoutConstraint(item: emailTextField, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1, constant: 50).isActive = true
NSLayoutConstraint(item: passwordTextField, attribute: .top, relatedBy: .equal, toItem: emailTextField, attribute: .bottom, multiplier: 1, constant: 8).isActive = true
NSLayoutConstraint(item: passwordTextField, attribute: .left, relatedBy: .equal, toItem: containerView, attribute: .left, multiplier: 1, constant: leftConstant).isActive = true
NSLayoutConstraint(item: passwordTextField, attribute: .width, relatedBy: .equal, toItem: containerView, attribute: .width, multiplier: 1, constant: widthConstant).isActive = true
NSLayoutConstraint(item: passwordTextField, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1, constant: 50).isActive = true
}
func setupLoginButton() {
NSLayoutConstraint(item: loginButton, attribute: .centerX, relatedBy: .equal, toItem: containerView, attribute: .centerX, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: loginButton, attribute: .top, relatedBy: .equal, toItem: passwordTextField, attribute: .bottom, multiplier: 1, constant: 16).isActive = true
NSLayoutConstraint(item: loginButton, attribute: .width, relatedBy: .equal, toItem: passwordTextField, attribute: .width, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: loginButton, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1, constant: 50).isActive = true
}
func setupRegisterLink() {
NSLayoutConstraint(item: registerLink, attribute: .centerX, relatedBy: .equal, toItem: containerView, attribute: .centerX, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: registerLink, attribute: .top, relatedBy: .equal, toItem: loginButton, attribute: .bottom, multiplier: 1, constant: 12).isActive = true
NSLayoutConstraint(item: registerLink, attribute: .width, relatedBy: .equal, toItem: loginButton, attribute: .width, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: registerLink, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1, constant: 40).isActive = true
}
}