如何将焦点设置在特定的小部件上

Question

I'm trying to implement GUI with various widgets for OpenGL project. I have a main widget for drawing the scene. The OpenGL widget is associated with Key and Mouse events, therefore the focus should always be on it. I've noticed if I click on say a push button, then the focus is moved to this button which means the focus is no longer associated with OpenGL widget. Clicking the widget by the mouse is not changing the focus. One of the solution is to turn off the focus for all widgets except the OpenGL widget in the GUI as follows

 ui->processButton->setFocusPolicy(Qt::NoFocus);
 ui->quitButton->setFocusPolicy(Qt::NoFocus);
 ui->clearButton->setFocusPolicy(Qt::NoFocus);
 ui->textEdit->setFocusPolicy(Qt::NoFocus);
 ui->groupBox->setFocusPolicy(Qt::NoFocus);

if I have many widgets, then this solution is annoying especially if I add widgets later on. My question is is there a solution to set the focus on a specific widget?

Answer 1

Your solution is fine, you just shouldn't be enumerating widgets manually:

// C++11
for (auto widget : findChildren<QWidget*>())
  if (! qobject_cast<QOpenGlWidget*>(widget)) widget->setFocusPolicy(Qt::NoFocus);

// C++98
foreach (QWidget * widget, findChildren<QWidget*>())
  if (! qobject_cast<QOpenGlWidget*>(widget)) widget->setFocusPolicy(Qt::NoFocus);