Items in QHBoxLayout layout overlap - c++

Question

I can't figure out what is wrong with Qt. I am trying to create a simple layout, like this:
+-------+-----------+
| | Label1 |
| Thumb |-----------+
| | Label2 |
| |(multiline)|
+-------+-----------+
And this is the code that does this:
labelInfoName = new QLabel("Sample name", this);
labelInfoDetails = new QLabel("Sample details...", this);
labelInfoDetails->setAlignment(static_cast<Qt::Alignment>(Qt::AlignTop | Qt::AlignLeft));
QVBoxLayout* textInfoLayout = new QVBoxLayout(this);
textInfoLayout->addWidget(labelInfoName);
textInfoLayout->addWidget(labelInfoDetails, 1);
// Create info pane
imgInfoThumbnail = new QLabel(this);
imgInfoThumbnail->setFixedSize(64, 64);
imgInfoThumbnail->setStyleSheet("background: black;");
QHBoxLayout* infoLayout = new QHBoxLayout(this);
infoLayout->addWidget(imgInfoThumbnail);
infoLayout->addLayout(textInfoLayout, 1)
this->setLayout(infoLayout);
And this is a QWidget. This is the code that sets up the layout in a class derived from QWidget. Then I want to display it as a dockable widget, which I do like this from my QMainWindow class:
widget = new Widget(this); // Widget that was set up above
QDockWidget* dockWidget = new QDockWidget("Project", this);
dockWidget->setWidget(widget);
addDockWidget(Qt::LeftDockWidgetArea, dockWidget);
But this is what I get instead:
I need the widget to be a custom control that I can place anywhere. Previously, it was defined as a QDockWidget, and instead of calling this->setLayout() I was creating a QWidget object, and this worked as expected:
QWidget* widget = new QWidget(this);
widget->setLayout(infoLayout);
this->setWidget(widget);
But the way I've done it now, it puts them on top of each other. What am I doing wrong?

Answer 1

You are creating layout incorrectly.
When you pass parent (widget) to a layout this layout is set automatically as layout to this widget.
Problem is that once layout is set for a widget it can't be changed, I'm pretty sure you are receiving some warning about this.
So just remove this when constructing a layout (at least in first case):
labelInfoName = new QLabel("Sample name", this);
labelInfoDetails = new QLabel("Sample details...", this);
labelInfoDetails->setAlignment(static_cast<Qt::Alignment>(Qt::AlignTop | Qt::AlignLeft));
QVBoxLayout* textInfoLayout = new QVBoxLayout();
textInfoLayout->addWidget(labelInfoName);
textInfoLayout->addWidget(labelInfoDetails, 1);
// Create info pane
imgInfoThumbnail = new QLabel(this);
imgInfoThumbnail->setFixedSize(64, 64);
imgInfoThumbnail->setStyleSheet("background: black;");
QHBoxLayout* infoLayout = new QHBoxLayout(this);
infoLayout->addWidget(imgInfoThumbnail);
infoLayout->addLayout(textInfoLayout, 1)
this->setLayout(infoLayout);