[Moved] Document/View application
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Thanks for the quick reply.
Creating "information.h" seems like a good solution, but how can I make it work? How would MainWindow own the working copy and pass it to the other classes?
In Qt I kept getting compile errors when I didn't include the struct keyword in places where it seemed redundant.
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Information.h:
@
struct Information {
// foo
};
@UserEntry.h:
@
#include "Information.h"
...
void userdata(Information *info) {...}; // Takes a pointer to info
// or
void userdata(Information &info) {...}; // Takes a reference to info
@MainWindow.h:
@
#include "Information.h"
...
private:
Information info;
UserEntry *userEntry;
@MainWindow.cpp:
@
MainWindow::someMethod() {
userEntry->userdata(&info); // Pass the address of info.
// or
userEntry->userdata(info); // using reference
}
@Edit: Corrected code. Thanks Gerolf!
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Note that you might want to use forward declares in headers instead of includes. That means:
@
//MainWindow.h
struct Information;//...
private:
Information* m_information;
@and then only in the MainWindow.cpp do the #include of Information.h.
It makes compilation faster.
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No luck - below is the MainWindow and Information code. I left out the UserData code to see if this would work before making it any more complex. This generates a compile error code:
request for member 'a' in 'info', which is of non-class type 'Information*'Is this caused by a syntax error that I am missing?
MainWindow.h
@
#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>
#include "Information.h"namespace Ui {
class MainWindow;
}class MainWindow : public QMainWindow
{
Q_OBJECTpublic:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();private:
struct information *info;private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
@MainWindow.cpp
@
#include "mainwindow.h"
#include "ui_mainwindow.h"MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{ui->setupUi(this); info = new information; info.a = "A"; info.b = "B"; info.c = "C";}
MainWindow::~MainWindow()
{
delete ui;
}
@Information.h
@
#ifndef INFORMATION_H
#define INFORMATION_H#include <QtGui>
struct information
{
QString a;
QString b;
QString c;
};#endif // INFORMATION_H
@
Added @ tags around code sections. Please do that yourself next time; Andre
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There seems to be some weird mismatch of #ifdefs and #endif's in your code. Perhaps you should fix these first?
Oh, and in your MainWindow, you have a pointer to an Information instance, while you do not seem to be creating an instance and trying to assign to it as if it is a normal member variable.
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Did you also note the remark I posted above?
[quote author="Andre" date="1315495737"]Oh, and in your MainWindow, you have a pointer to an Information instance, while you do not seem to be creating an instance and trying to assign to it as if it is a normal member variable. [/quote]
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Either, change line 20 in MainWindow.h to
@
Information info;
@
and remove line 13 from MainWindow.cpp, orchange line 20 in MainWindow.h to
@
Information* info;
@
and change lines 15-17 in MainWindow.cpp into:
@
info->a = "A";
info->b = "B";
info->c = "C";
@
and insert this line as line 24:
@
delete info;
@In either case, get yourself a good book on C++ to get yourself a solid introduction into the language you are working with. Qt does not shield you from having to learn C++.
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Andre (and everyone else)-
Thanks for your help. The first option compiled correctly. Having seen something that works I hope I can figure it out from here.
Your last suggestion is appropriate. However, I have a large stack of books on C++ programming. The problem is the definition of the word "good". I learned chemical thermodynamics by using a large stack of textbooks. None of them were particulary good. But, where one authors explanation failed another author provided a more thorough explanation. I was able to piece it together that way. I haven't found that approach to work well for understanding C++.