Signals/slots between classes

[Tanuki-no Torigava]

And just notice that you close the namespace Ui. So your declaration is incorrect. It should be

class Ui::Widget: public QWidget;

class Ui::Widget: public QWidget;

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Also it is a bit strange declaration. Is it designer-made class?

[been_1990]

And just notice that you close the namespace Ui. So your declaration is incorrect. It should be

class Ui::Widget: public QWidget;

class Ui::Widget: public QWidget;

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Also it is a bit strange declaration. Is it designer-made class?

That's code generated from QtCreator.

[Tanuki-no Torigava]

Actually, that WOULD produce an error, but at runtime when connect() is called, rather than compile time. You'll get an error stating that there's no such signal.

I mean compile time error. Actually I do prefer to see compile time error instead of looking through the console. So you are half right. Run time error != build time error.

About dialog. Looks like you draw in designer, right? if so you need multiple inheritance where the first class is exactly the base class of your widget (QDialog, QScrollArea, etc) and second is your Ui based class.

// Login details dialog
class LoginDetails : public QDialog, public Ui::SyncDialog
{
Q_OBJECT
 
public:
 
    LoginDetails(QWidget * parent = 0, Qt::WindowFlags f = 0);
   ~LoginDetails();
}
 
// And in the constructor of this class very urgent to keep the initialization sequence and don't forget to initialize Ui as well
 
LoginDetails::LoginDetails(
        QWidget*        parent,
        Qt::WindowFlags flags)
    :   QDialog(parent, flags)
{
   setupUi(this); // should go first!!!
 
   // Your init
 
}

// Login details dialog
class LoginDetails : public QDialog, public Ui::SyncDialog
{
Q_OBJECT

public:

    LoginDetails(QWidget * parent = 0, Qt::WindowFlags f = 0);
   ~LoginDetails();
}

// And in the constructor of this class very urgent to keep the initialization sequence and don't forget to initialize Ui as well

LoginDetails::LoginDetails(
        QWidget*        parent,
        Qt::WindowFlags flags)
    :   QDialog(parent, flags)
{
   setupUi(this); // should go first!!!

   // Your init

}

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Hope that helps

[squidge]

I mean compile time error. Actually I do prefer to see compile time error instead of looking through the console. So you are half right. Run time error != build time error.

I thought I clearly stated that in my post:

Actually, that WOULD produce an error, but at runtime when connect() is called, rather than compile time. You'll get an error stating that there's no such signal.

It was a "Just for your information". I know it's not a compile time error, but you might not have known about it and thought it was useful. Considering connect() takes a char *, it's impossible for it to know at compile time that a signal doesn't exist. You can put whatever you like for the signal and slot and it'll be happy at compile time.

[been_1990]

I mean compile time error. Actually I do prefer to see compile time error instead of looking through the console. So you are half right. Run time error != build time error.

About dialog. Looks like you draw in designer, right? if so you need multiple inheritance where the first class is exactly the base class of your widget (QDialog, QScrollArea, etc) and second is your Ui based class.

// Login details dialog
class LoginDetails : public QDialog, public Ui::SyncDialog
{
Q_OBJECT
 
public:
 
    LoginDetails(QWidget * parent = 0, Qt::WindowFlags f = 0);
   ~LoginDetails();
}
 
// And in the constructor of this class very urgent to keep the initialization sequence and don't forget to initialize Ui as well
 
LoginDetails::LoginDetails(
        QWidget*        parent,
        Qt::WindowFlags flags)
    :   QDialog(parent, flags)
{
   setupUi(this); // should go first!!!
 
   // Your init
 
}

// Login details dialog
class LoginDetails : public QDialog, public Ui::SyncDialog
{
Q_OBJECT

public:

    LoginDetails(QWidget * parent = 0, Qt::WindowFlags f = 0);
   ~LoginDetails();
}

// And in the constructor of this class very urgent to keep the initialization sequence and don't forget to initialize Ui as well

LoginDetails::LoginDetails(
        QWidget*        parent,
        Qt::WindowFlags flags)
    :   QDialog(parent, flags)
{
   setupUi(this); // should go first!!!

   // Your init

}

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Hope that helps

You lost me here... Let me see if I understood right, I should use Multiple Inheritance instead of Single Inheritance? The code generated by QtCreator seems to be single inheritance, I never changed that, but is that necessary?
Yes I use the designer to create the forms..

[squidge]

Multiple Inheritance is generally a bad idea. You should use single inheritance unless you have a good reason. This way all your ui objects are behind the 'ui' object rather than exposed and polluting the same class as your implementation. Multiple inheritance also makes it more messy if another class includes your classes header file.

[been_1990]

Multiple Inheritance is generally a bad idea. You should use single inheritance unless you have a good reason. This way all your ui objects are behind the 'ui' object rather than exposed and polluting the same class as your implementation. Multiple inheritance also makes it more messy if another class includes your classes header file.

I read at QT archives that QT Creator uses single inheritance because that compiles much quicker and etc, etc ...
But there's this QT beginners tutorial that says multiple inheritance is the preferred way to write Qt applications.
Whatever.... So single inheritance is better?

[squidge]

Use whichever you prefer. I prefer single inheritance as it keep the ui private, but some prefer multiple so they can access the ui directly.