Was not declared in this scope

[A Former User]

Hello,
I have a question…

   QFile inputFile(":/Table.htm");
   inputFile.open(QIODevice::ReadOnly);
   QTextStream in(&inputFile);
   QString line = in.readAll();
   inputFile.close();
       w->append(line);

w was not declared in this scope. I know that.

The Code is written in Start.cpp

I declared w in Mainwindow.h

How can i use the w from Mainwindow.h in Start.cpp?

Thanks

[SGaist]

Hi,

Sounds like you are trying to access internal details of a class from another one which is a bad idea.

Add a function to MainWindow to modify w but don't try to access it from another class like that.

[yuvaram]

Hi @HenrikSt
This sample code may help you.
widget.cpp

#include "widget.h"
widget::widget(QObject *parent) : QObject(parent)
{
}
void widget:: setValueX(int val){
xValue = val;
qDebug()<<Q_FUNC_INFO<<"Xval ::"<<xValue<<endl;
}
int widget:: getValueX(){
qDebug()<<Q_FUNC_INFO<<"Xval ::"<<xValue<<endl;
return xValue;
}

start.h

#include "widget.h"
class start : public QWidget
{
Q_OBJECT
public:
explicit start(QWidget parent = 0);
void SetWidgetpointer(QObject);

signals:

public slots:
private:
widget *wgtobj;
};

start.cpp

#include "start.h"
start::start(QWidget parent) : QWidget(parent)
{}
void start:: SetWidgetpointer(QObject obj){
wgtobj = qobject_cast<widget*>(obj);
qDebug()<<Q_FUNC_INFO<<"> valueX ::"<<wgtobj->getValueX()<<endl;
}

mainwindow.cpp

#include "mainwindow.h"
#include "start.h"

MainWindow::MainWindow(QWidget *parent)
: QWidget(parent)
{
widget w;
w.setValueX(100);
start strtObj;
strtObj.SetWidgetpointer(&w);

}

Execute the above code, you will get clear idea of implementation.

[SGaist]

@yuvaram That's really not a clean implementation. You're creating an unneeded tight coupling that will only result in a maintenance nightmare.

[mrjj]

Hi
w is your textedit ?
Would be easier just to make that function in mainwin.
Do you mean something like this?

start.cpp
void InsertResTable(QString &line) {
   QFile inputFile(":/Table.htm");
    inputFile.open(QIODevice::ReadOnly);
   QTextStream in(&inputFile);
   line = in.readAll();
   inputFile.close();       
}

in start.h
void InsertResTable(QString &line);

in maindow.
#include "start.h"
... when u click?
QString line;
InsertResTable(line);
w->append(line);

disclaimer: not tested.

[yuvaram]

Hi @SGaist
Can you please share right way of implementation in this scenario.
Any other way of implementation.
Thank you.

[jsulm]

@yuvaram Just use signals/slots to exchange data between classes and to trigger actions. Do NOT access internal details (like member variables) of a UI class from another one.

[yuvaram]

@jsulm Yes, i agree with you. But as per above requriment i gave that sample.