Qt - remove all widgets from layout?

Question

This doesn\'t seem easy. Basically, I add QPushButtons through a function to a layout, and when the function executes, I want to clear the layout first (removi

Answer 1

You also want to make sure that you remove spacers and things that are not QWidgets. If you are sure that the only things in your layout are QWidgets, the previous answer is fine. Otherwise you should do this:

QLayoutItem *wItem;
while (wItem = widget->layout()->takeAt(0) != 0)
      delete wItem;

It is important to know how to do this because if the layout you want to clear is part of a bigger layout, you don't want to destroy the layout. You want to ensure that your layout maintains it's place and relation to the rest of your window.

You should also be careful, you're are creating a load of objects each time you call this method, and they are not being cleaned up. Firstly, you probably should create the QWidget and QScrollArea somewhere else, and keep a member variable pointing to them for reference. Then your code could look something like this:

QLayout *_layout = WidgetMemberVariable->layout();

// If it is the first time and the layout has not been created
if (_layout == 0)
{
  _layout = new QVBoxLayout(this);
  WidgetMemberVariable->setLayout(_layout);
}

// Delete all the existing buttons in the layout
QLayoutItem *wItem;
while (wItem = widget->layout()->takeAt(0) != 0)
    delete wItem;

//  Add your new buttons here.
QPushButton button = new QPushButton(item);
_layout->addWidget(button);

QPushButton button = new QPushButton("button");
_layout->addWidget(button);