Question

I know this question has been asked a few time, (http://stackoverflow.com/questions/4436511/display-a-form-in-qt)

I am trying to open an existing form in my Qt C++ project.
it needs to be a subform instead of QDialog box.

both forms have a .ui, .h and .cpp file with them.

in my mwindowtest.cpp I have

//this is used to handle the button click to open the new form
connect(btnConnect, SIGNAL(click()), this, SLOT(openNewWindow()));

for function is:

void mWindowTest::openNewWindow(){

   mForm = new dialog (this);
   mForm->show();

}

in my mwindowtest.cpp I have:

#include <dialog.h>  //second form
class dialog;

I’m now getting the error mForm was not declared in this scope.
but I am not sure what to declare mForm as in my Header file.

any tips would be greatly appreciated.

Thanks

Answer 1

In your example you will have memory leak since each time button btnConnect is clicked you will reallocate memory for your form, without deleting the previous first.

Concerning your problem, we need to know how is declare dialog in dialog.h to be able to really help you.
In your mywindowtest.cpp you have included the file and redefined the class. Try to put

class dialog

in your hpp file and

#include <dialog.h>

in your cpp file.

Hope that helps

Edit:

In your slot:

delete mForm;
mForm = new dialog();
dialog->show();

It’s the minimum to avoid memory leaks; And don’t forget to delete mForm in MyWindowTest destructor too if not null;