QWidget::setLayout: Attempting to set QLayout "" on Widget "", which already has a layout

c++, layout, qt, widget

Solution

So I believe your problem is in this line:

QHBoxLayout *hlayout = new QHBoxLayout(this);

In particular, I think the problem is passing `this` into the `QHBoxLayout`. Because you intend for this `QHBoxLayout` to NOT be the top level layout of `this`, you should not pass `this` into the constructor.

Here's my re-write that I hacked into a test app locally and seems to work great:

Widget::Widget(QWidget *parent) :
    QWidget(parent)
{
    QLabel *label = new QLabel("Test");
    QHBoxLayout *hlayout = new QHBoxLayout();
    QVBoxLayout *vlayout = new QVBoxLayout();
    QSpacerItem *spacer = new QSpacerItem(40, 20, QSizePolicy::Fixed);
    QLineEdit *lineEdit = new QLineEdit();
    hlayout->addItem(spacer);
    hlayout->addWidget(lineEdit);
    vlayout->addLayout(hlayout);
    vlayout->addWidget(label);
    setLayout(vlayout);
}

Problem

Original source