How to access QT element from different file

andyc

Hello everybody, im pretty new to -QT- Qt (installed it only today), and i have this very simple application:

i have created -QT- Qt widget project, and i have these files
main.cpp
mainwindow.cpp
mainwindow.h
ui_mainwindow.h
mainwindow.ui

so, the main window is created and i have added a new element via designer in mainwindow.ui - a simple text area named textEdit

so my question is, how i can write something into this textEdit from main.cpp

when i try

@textEdit->setText("test");@

it says that textEdit is undeclared, and i know that it is declared in ui_mainwindow.h i just dont know how to tell it to the main.cpp file
ive been sitting on this for few hours, and could not figure anything, i found out, that ui_mainwindow.h is using namespace
@namespace Ui {
class MainWindow: public Ui_MainWindow {};
} // namespace Ui@

so i tried something like
@Ui::MainWindow->textEdit->setText("test");@
but that does not work either...

//i figured out that i can access textEdit withing mainwindow.cpp using ui->textEdit->setText(); and i would like to do the same, but from the main.cpp

So could someone help me, how to make this simple thing works ? :)

Best Regards,
andyc

ShadowMoses

You normally create a new class that is a subclass of QMainWindow and your Ui created class like so in your mainwindow.cpp.
@class MainWindow : public QMainWindow, public Ui::MainWindow@

Then you could use textEdit.setText("test") in the constructor of your MainWindow.

You could also create a pointer to the Ui::MainWindow in the private section of your MainWindow implementation like so.
@private:
Ui::MainWindow ui;@

Then in your MainWindow constructor your would have to do ui.setupUi(this); instead of just setupUi(this).
Then change text edit like this. ui.textEdit->setText("test");

Hope this helps.

andyc

But i have everything like you said , i am using Qt Creator, and it generated code for me - i did not edit these files
and it looks like this:

mainwindow.cpp and it looks like
@#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

}

MainWindow::~MainWindow()
{
delete ui;
}
@

and mainwindow.h
@#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H@

and ui_mainwindow.h
@
QT_BEGIN_NAMESPACE

class Ui_MainWindow
{
public:
QWidget *centralwidget;
QTextEdit *textEdit;
QMenuBar *menubar;
QStatusBar *statusbar;

void setupUi(QMainWindow *MainWindow)
{
    if (MainWindow->objectName().isEmpty())
        MainWindow->setObjectName(QString::fromUtf8("MainWindow"));
    MainWindow->resize(800, 600);
    centralwidget = new QWidget(MainWindow);
    centralwidget->setObjectName(QString::fromUtf8("centralwidget"));
    textEdit = new QTextEdit(centralwidget);
    textEdit->setObjectName(QString::fromUtf8("textEdit"));

.
.
.
retranslateUi(MainWindow);

    QMetaObject::connectSlotsByName(MainWindow);
} // setupUi

void retranslateUi(QMainWindow *MainWindow)
{
    MainWindow->setWindowTitle(QApplication::translate("MainWindow", "MainWindow", 0, QApplication::UnicodeUTF8));
} // retranslateUi

};

namespace Ui {
class MainWindow: public Ui_MainWindow {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_MAINWINDOW_H
@

and finally, qt generated main.cpp and
main.cpp

@
#include <QtGui/QApplication>
#include "mainwindow.h"
int main(int argc, char *argv[]) {
QApplication app(argc, argv);

MainWindow w;
w.show();

textEdit->setText("test"); //i would like to write to the textEdit in the main.cpp not in the
// mainwindow.cpp and i get error: 'textEdit' was not declared in this scope
return app.exec();
}
@

again, i know how to user textEdit in mainwindow.cpp, but i dont know how to use it in main.cpp, thats my problem..

Thansk.

giesbert

No, you don't. You have

@
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

private:
Ui::MainWindow *ui;
};
@

which means, you have a pointer to the ui. This means, you must use text edit like this:

@
ui->textEdit->setText("test");
@