How do I modify function to be used in MVP architecture?

Question

I have the function below. It works properly.

When a user types any character it validates the user input and hides some imageView based on the input.

@IBAction func onEmailValueChanged(_ sender: UITextField) {
    let hasMinimumLength = TextValidationHelper.validateHasMinimumLength(password: sender.text!)
    passLengthCheckmarkImageView.isHidden = hasMinimumLength ? false : true
    let hasCapitalLetter = TextValidationHelper.validateHasCapitalLetter(password: sender.text!)
    passHasUppercaseCheckmarkImageView.isHidden = hasCapitalLetter ? false : true
    let hasNumber = TextValidationHelper.validateHasNumber(password: sender.text!)
    passHasNumberCheckmarkImageView.isHidden = hasNumber ? false : true
    let hasSpecialCharacter = TextValidationHelper.validateHasSpecialCharacter(password: sender.text!)
    passHasSymbolCheckmarkImageView.isHidden = hasSpecialCharacter ? false : true
    
    resetButton.isHidden = hasMinimumLength && hasCapitalLetter && hasNumber && hasSpecialCharacter ? false : true 
}

But now I want to apply an MVP model on this function to remove the function from the ViewController file. How can I do that?

Do I need to publish more code to make it possible to create an answer for this question?

Answer 1

It is not a good practice to use any architectural pattern only for method. So assuming you are having a complete app with many classes or files.

An important thing is that it is not fixed/compulsory to use any specific pattern. It actually depends on the code, sometimes you end up writing much code just to handle a method. So try to think the optimal approach to make the code more testable and scalable.

But for your reference, you can check the following code:

On ViewController:

lazy var presenter:Presenter = Presenter(view:self)


 @IBAction func onEmailValueChanged(_ sender: UITextField) {
    presenter.validateHasMinimumLength(password: sender.text!)
    presenter.validateHasCapitalLetter(password: sender.text!)
    presenter.validateHasNumber(password: sender.text!)
    presenter.validateHasSpecialCharacter(password: sender.text!)
}

//Adopting ViewController:PrensenterViewProtocol on ViewController

extension ViewController:PrensenterViewProtocol {

func updateLengthCheckmarkImageView(isHidden:Bool) {
    passLengthCheckmarkImageView.isHidden = isHidden
}

func updateUpperCaseCheckmarkImageView(isHidden:Bool) {
    passHasUppercaseCheckmarkImageView.isHidden = isHidden
}

func updateNumberCheckmarkImageView(isHidden:Bool) {
    passHasNumberCheckmarkImageView.isHidden = isHidden
}

func updateSymbolCheckmarkImageView(isHidden:Bool) {
    passHasSymbolCheckmarkImageView.isHidden = isHidden
}

func updateResetButton(isHidden:Bool) {
    resetButton.isHidden = isHidden
}

}

PresenterView protocol as:

protocol PrensenterViewProtocol:NSObjectProtocol {
    func updateLengthCheckmarkImageView(isHidden:Bool)
    func updateUpperCaseCheckmarkImageView(isHidden:Bool)
    func updateNumberCheckmarkImageView(isHidden:Bool)
    func updateSymbolCheckmarkImageView(isHidden:Bool)
    func updateResetButton(isHidden:Bool)
}

Presenter as:

class Presenter {
weak var view:PrensenterViewProtocol!
private var hasMinimumLength:Bool = false
private var hasCapitalLetter:Bool = false
private var hasNumber:Bool = false
private var hasSpecialCharacter:Bool = false

init(view:PrensenterViewProtocol) {
    self.view = view
}
    
func validateHasMinimumLength(password:String?) {
    hasMinimumLength = TextValidationHelper.validateHasMinimumLength(password: password)
    self.view.updateLengthCheckmarkImageView(isHidden: hasMinimumLength)
    checkAllValidations()
}

func validateHasCapitalLetter(password:String?) {
    hasCapitalLetter = TextValidationHelper.validateHasCapitalLetter(password: password)
    self.view.updateUpperCaseCheckmarkImageView(isHidden:hasCapitalLetter )
    checkAllValidations()
}

func validateHasNumber(password:String?) {
    hasNumber = TextValidationHelper.validateHasNumber(password: password)
    self.view.updateNumberCheckmarkImageView(isHidden: hasNumber)
    checkAllValidations()
}

func validateHasSpecialCharacter(password:String?) {
    hasSpecialCharacter = TextValidationHelper.validateHasSpecialCharacter(password: password)
    self.view.updateSymbolCheckmarkImageView(isHidden: hasSpecialCharacter)
    checkAllValidations()
}

func checkAllValidations() {
    let areAllValid:Bool = hasMinimumLength && hasCapitalLetter && hasNumber && hasSpecialCharacter ? false : true
    self.view.updateResetButton(isHidden: areAllValid)
}

}