Create an instance of QScopedPointer later

Question

For example here is my code

QScopedPointer<QTimer> timer2(new QTimer);

But I want to define

QScopedPointer<QTimer> timer2; 

in mainwindow.h and create an instance

timer2(new QTimer);

in the mainwindow.cpp

How?

Answer 1

Try the following:

// mainwindow.h
class MainWindow : public QMainWindow
{
private:
    QScopedPointer<QTimer> timer2;
};

If you want to create the instance in the constructor, use the following:

// mainwindow.cpp
MainWindow::MainWindow()
    :timer2(new QTimer)
{
}

Alternately, if you want to create the instance in some arbitrary member function of MainWindow, use this:

// mainwindow.cpp
void MainWindow::someFunction()
{
    timer2.reset(new QTimer);
}

It's also worth reviewing initialization lists in C++ and the documentation for QScopedPointer.