TextFieldValidationError.swift

//
//  TextFieldValidationError.swift
//  TFTextField
//
//  Created by Tobias Feistmantl on 07/09/15.
//  Copyright (c) 2015 Tobias Feistmantl. All rights reserved.
//

import Foundation

enum TextFieldValidationError: String {
    case Empty = "The field is empty"
    case TooShort = "The value is too short"
    case TooLong = "The value is too long"
    case InvalidEmailAddress = "This isn't a valid email address"
}

TFTextField.swift

//
//  TFTextField.swift
//  TFTextField
//
//  Created by Tobias Feistmantl on 07/09/15.
//  Copyright (c) 2015 Tobias Feistmantl. All rights reserved.
//

import Foundation

@IBDesignable class TFTextField: UITextField {
    // To be valid...
    
    // ...the text field can't be blank
    @IBInspectable var mustBePresent: Bool = false
    // ...the value must have a minimum length
    @IBInspectable var minimumLength: Int = 0
    // ...the value could not have a bigger value
    @IBInspectable var maximumLength: Int = 0
    // ...the value must be a valid email address
    @IBInspectable var isEmailAddress: Bool = false
    
    // The error info label
    // Will be set only if an error is set
    // and set to nil if the error will be removed
    var errorLabel: UILabel?
    
    // Returns true if the given email string has a valid format
    func isValidEmail(testString: String) -> Bool {
        return NSPredicate(format:"SELF MATCHES %@", "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,6}").evaluateWithObject(testString)
    }
    
    // Validates the value
    // Based on the configured settings the value will be valid or not
    // Returns a TextFieldValidationError if the value is invalid or nil if not
    var validationError: TextFieldValidationError? {
        if mustBePresent && empty {
            return .Empty
        }
        
        if minimumLength != 0 && text.length < minimumLength && (mustBePresent || filled) {
            return .TooShort
        }
        
        if maximumLength != 0 && text.length > maximumLength {
            return .TooLong
        }
        
        if isEmailAddress && !isValidEmail(text) && (mustBePresent || filled) {
            return .InvalidEmailAddress
        }
    }
    
    
    // Returns true if the value is valid
    var valid: Bool {
        return validationError == nil
    }
    
    // Returns true if the value is invalid
    var invalid: Bool {
        return validationError != nil
    }
    
    // Set validation error label in the left side of the text field
    // Should be only used with wide text fields!
    func setInlineErrorMessage(value: String) {
        if errorLabel == nil {
            let errorColor = UIColor(hex: "AA0000")
            
            self.textColor = errorColor
            
            self.errorLabel = UILabel()
            errorLabel!.textColor = errorColor
            errorLabel!.font = self.font
            errorLabel!.textAlignment = .Right
            errorLabel!.setTranslatesAutoresizingMaskIntoConstraints(false)
            
            errorLabel!.text = value
            
            self.addSubview(errorLabel!)
            
            let centerConstraint = NSLayoutConstraint(item: self, attribute: .CenterY, relatedBy: .Equal, toItem: errorLabel, attribute: .CenterY, multiplier: 1, constant: 0)
            let rightConstraint = NSLayoutConstraint(item: self, attribute: .Trailing, relatedBy: .Equal, toItem: errorLabel, attribute: .Trailing, multiplier: 1, constant: 0)
            
            self.addConstraints([centerConstraint, rightConstraint])
        }
    }
    
    // Set error info based on the validation error
    func setInlineErrorMessageByValidationError() {
        if let error = validationError {
            setInlineErrorMessage(error.rawValue)
        }
    }
    
    // Reset error information
    func resetError() {
        self.textColor = .blackColor()
        errorLabel?.removeFromSuperview()
        errorLabel = nil
    }
    
    // Compares it's own value with another textfields value
    // and return true if the values are equal
    func hasEqualValue(textField: UITextField) -> Bool {
        return text == textField.text
    }
    
    // Returns true if the text field is empty
    var empty: Bool {
        return text == ""
    }
    
    // Returns true if a value is present
    var filled: Bool {
        return text != ""
    }
}