Question

How do I do this:

For instance, label username = “user”

I click a button and a dialog box appears which asks for an input. I enter “name” in the input box and click ok. Now how do i make it so that the label username will automatically change to “name” when I click on the ok button on the dialog box?

This value goes to the Settings value. I know how to load a value from a setting, but if my label username and the input box in which i entered “name” are in 2 different classes, how do i cause the change? please help.

Answer 1

You need to use signals and slots. In class where you have this QLineEdit you have to declare signal like

class SomeClass : public QDialog     //or other inheritance
{
    /* constructors, functions and other stuff */
    signals:
         void valueChanged(const QString&);        //in QString you will send new value
}

After someone click ‘Ok’ button you have to emit this signal:

emit valueChanged(myQLineEdit->text());

And in class where you invoke SomeClass you have to connect this signal to slot in which you will change labels value, for example:

void MainWindow::someMethod()
{
    SomeClass *class = new SomeClass;
    connect(class, SIGNAL(valueChanged(QString)), this, SLOT(changeValue(QString)));
    /* set other parameters, show window*/
}

void MainWindow::changeValue(const QString &newText)
{
    myQLabel->setText(newText);
}