dwarf issue

[hollowhead]

Yes but how do get round this, what code do I need to write? I need to pass data from the mytestdialog class to the spreadsheet class. Thanks.

[calhal]

mytestdialog must have a correct pointer to the spreadsheet, assuming this spreadsheet was created somewhere, for example in the mainwindow
You can make a pointer to the spreadsheet class a member of your dialog class and then initialize it by passing a pointer to the constructor of this dialog or via a setter method (which you have to define) just after creating mytestdialog and before executing it.

[hollowhead]

calhal,

I accept what you say and I've read your post very carefully, I've looked in my C++ books and online but I haven't a clue how to do this. I've tried several things including making my Spreadsheet class a friend of my dialog class (compiles but same error) and several other methods but these wouldn't compile. I would be very grateful if you could post some code or a link to a tutorial that shows this since I'm really stuck here.... Ta.

[wysota]

I need to pass data from the mytestdialog class to the spreadsheet class.

You don't pass data to classes, you pass it to objects.
You can have multiple objects of the same class. You need to reference the exact same Spreadsheet object you created earlier, you can't just declare a pointer to its class.

[calhal]

I've just noticed that you're creating and executing this dialog in spreadsheet so you have already passed the pointer to spreadsheet to the dialog here:

MyTestDialog = new MyTestDialog(this);

MyTestDialog = new MyTestDialog(this);

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you can access public members of spreadsheet through parent-> within your dialog

But to show you what I wrote before:

(...)
#include "spreadsheet.h"
class MyTestDialog : public QDialog, public Ui::MyTestDialog {
  Q_OBJECT
  public:
    MyTestDialog( QWidget * parent = 0, Qt::WFlags f = 0, Spreadsheet *spr = 0);
(...)
  private :
    Spreadsheet *spreadsheet;
(...)

(...)
#include "spreadsheet.h"
class MyTestDialog : public QDialog, public Ui::MyTestDialog {
  Q_OBJECT
  public:
    MyTestDialog( QWidget * parent = 0, Qt::WFlags f = 0, Spreadsheet *spr = 0);
(...)
  private :
    Spreadsheet *spreadsheet;
(...)

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and then

MyTestDialog::MyTestDialog( QWidget * parent, Qt::WFlags f, Spreadsheet *spr) {
(...)
  spreadsheet = spr;
}
 
(...)
 
void MyTestDialog::onCalc1() {
  if (spreadsheet) // Don't forget to check if spreadsheet is not null
     spreadsheet->tests();
}

MyTestDialog::MyTestDialog( QWidget * parent, Qt::WFlags f, Spreadsheet *spr) {
(...)
  spreadsheet = spr;
}

(...)

void MyTestDialog::onCalc1() {
  if (spreadsheet) // Don't forget to check if spreadsheet is not null
     spreadsheet->tests();
}

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and then in the code where you want to run this dialog

dialog = new MyTestDialog(this, 0, pointer_to_spreadsheet)

dialog = new MyTestDialog(this, 0, pointer_to_spreadsheet)

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[JD2000]

A Spreadsheet object needs to be created somewhere in the programme first

Spreadsheet *spreadsheet = new Spreadsheet

Spreadsheet *spreadsheet = new Spreadsheet

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although I would be inclined to call the object something else to prevent confusion with the class name.

[hollowhead]

Wsoyta you are of course right, I do find this business of objects coming from C confusing. JD2000 I made your changes (thanks) I get a crash so bad the program never appears.

QWidget: Must construct a QApplication before a QPaintDevice

The reason is this code here which I placed in my spreadsheet.cpp code.

Spreadsheet *spreadsheet1 = new Spreadsheet;

Spreadsheet *spreadsheet1 = new Spreadsheet;

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Since adding Spreadsheet *spreadsheet1; in the spreadsheet.cpp file runs but has a null pointer again.

and using

myTestDialog = newmyTestDialog(this, 0, spreadsheet1);

myTestDialog = newmyTestDialog(this, 0, spreadsheet1);

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I assume the problem is my application is an mdi app so I have a mainwindow class that does this

void MainWindowImpl::createMdiWindow(const QString &fileName)
{
    Spreadsheet *spreadsheet = new Spreadsheet;
    QMdiSubWindow *subWindow = mdiArea->addSubWindow(spreadsheet);
    subWindow->show();
    if (!fileName.isEmpty()) {
       spreadsheet->load(fileName);
        statusBar()->showMessage(tr("File loaded"), 2000);
    }
}

void MainWindowImpl::createMdiWindow(const QString &fileName)
{
    Spreadsheet *spreadsheet = new Spreadsheet;
    QMdiSubWindow *subWindow = mdiArea->addSubWindow(spreadsheet);
    subWindow->show();
    if (!fileName.isEmpty()) {
       spreadsheet->load(fileName);
        statusBar()->showMessage(tr("File loaded"), 2000);
    }
}

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This then creates a mdi spreadsheet (tablewidget) window and sets up some formatting etc. Is there any way round this? Ta.

[wysota]

I think it would be best if you learned a bit of C++ before starting with Qt.

[JD2000]

JD2000 I made your changes (thanks) I get a crash so bad the program never appears.

What changes would those be? I simply pointed out that you did not have a spreadsheet object, presumably because it was renamed spreadsheet1. See line #0 in your back trace.

Generally you can not call object functions when the object does not exist.

[JD2000]

One of these might work

#
void MyTestDialog::onCalc1()
#
{
 
//QMdiArea->activeSubWindow->spreadsheet->tests(); // pass list into test function
QMdiArea->activeSubWindow->tests(); // pass list into test function
 
}

#
void MyTestDialog::onCalc1()
#
{
 
//QMdiArea->activeSubWindow->spreadsheet->tests(); // pass list into test function
QMdiArea->activeSubWindow->tests(); // pass list into test function

}

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[hollowhead]

Thanks very much JD2000 will try it if it fails will redsign app, call on stack and do calcs after closing dialog. Thanks.