Login screen (How to?)

[cxam]

Hi! I designed my Qt Gui application using QtDesigner and in order to make diverse layers inside the application (login, main menu, settings, etc.) I made diverse QWidgets for each layer and depending which button inside the GUI was pressed the layers where showing or hiding... Now I have to make all this cool buttons functional and I have to make the login screen usable but I don't know how, in my login screen I have 4 elements: 1: the logo, 2&3: Username and Password QLineEdits and 4: The "Enter" button. I have to make all those funcitional.

Thanks in advance:

Carlos.

[SGaist]

Hi,

What are you going to validate your username/password ? Database ? Local file ?

[cxam]

Just a string, the username and pasword wont be changed

[kshegunov]

@cxam

Just a string, the username and pasword wont be changed

Just to put a note here - if you use a C++ string for the username and password suppose like this:

const char * password = "my very secret password";

No one can stop me (or anyone else) from loading your application/library in the disassembler and extracting that string. So do consider this, when thinking about passwords.

[cxam]

Yeah I know that it may not be really secure but I just want it to work the easiest way posible, anyways I still dont know how to make the username / password validation system

[kshegunov]

@cxam
It's an ordinary dialog, is it not?

[cxam]

no, it's not the login takes places in the only window of the software: "mainwindow" when you enter the correct credentials then the login disappears and show the whole thing.

[SGaist]

Well since it's only a very light login, put the logic in the widget and emit a signal when the login is successful. Then in your main window react on that signal and do the changes needed.

[cxam]

@SGaist I have, really little C++ knowledge, would you please tell me the code I have to add ? Thanks in advance

[SGaist]

Do you mean the comparison logic ?

[cxam]

@SGaist Yes.

[SGaist]

Something like

void MyLoginWidget::onOkButtonClicked() 
{
    if (_usernameLineEdit->text() == MyValidUserName &&
        _passwordLineEdit->text() == MyTopSecretPassword) {
        emit loginSuccessful();
    } else (
        QMessageBox::warning(this, tr("Error"), tr("Invalid username/password combination");
        _usernameLineEdit->clear();
        _passwordLineEdit->clear();
    }
}

WARNING: this is just a quick and dirty sample code.

[cxam]

@SGaist So I have to add that code on "mainwindow.ccp" right ? (Sorry about my C++ knowledge haha)

[SGaist]

No, in the login widget. The MainWindow widget should only react on the loginSuccessful signal.

[cxam]

@SGaist I hope this will show you more or less how I have my project structured: http://postimg.org/gallery/oeciyc12/660b7d39/

[SGaist]

Ok… So you are trying to have everything in only once widget. Not a good idea. You should following the "Single Responsibility" paradigm. Create one widget per "complex" widget you will have in your main window. Otherwise you will end up with a monster class that does way to much things for its own good and yours to maintain.

[cxam]

@SGaist Yeah, I knew that my weird distribution would bring problems hahah. So I'll have to change it. Can you tell me which is the best distribution since I want that EVERYTHING happens in just one window (When I have the project finished I will embed it) ?

[SGaist]

Creating several widgets doesn't mean to you will have one application window per widget. What I'm suggesting is to separate things code-wise. You will still have only one MainWindow in the end containing everything but cleanly separated from a coding point of view.

[cxam]

@SGaist Ok, I've created a new project > application > QtWidgets application then it created the "MainWindow" class, "MainWindow" header and "MainWindow" Ui.
So for each "screen" I have to create a new C++ class ? Or... How? I don't understand the way to create widgets...

[SGaist]

Yes, create a new C++ class. You will have the option to "pre-populate" it for design development. You should take the time to look at Qt Creator/Designer and Qt's tutorial about how to create UI with Designer.