How to align QLabel correctly in a QGridLayout? - c++

Question

I am trying to align QLabels in a simple GridLayout but this doesn't work seems to be a bug in QT 5.9 ?
Here is my snippet, everything is in a QDialog:
MyDialogue::MyDialogue(QWidget *parent) : QDialog(parent) {
QLabel *labelA = new QLabel(); labelA->setFixedSize(100, 25);
QLabel *labelB = new QLabel(); labelB->setFixedSize(100, 25);
QLabel *labelC = new QLabel(); labelC->setFixedSize(100, 25);
QLabel *labelD = new QLabel(); labelD->setFixedSize(100, 25);
labelA->setStyleSheet("background-color:blue");
labelB->setStyleSheet("background-color:yellow");
labelC->setStyleSheet("background-color:purple");
labelD->setStyleSheet("background-color:green");
QGridLayout *layout = new QGridLayout(this);
layout->addWidget(labelA, 1, 1);
layout->addWidget(labelB, 1, 2);
layout->addWidget(labelC, 2, 1, 2, 2);
layout->addWidget(labelD, 3, 1, 3, 2);
}
The result:

Answer 1

Ok I found the solution (my mistake) :
MyDialogue::MyDialogue(QWidget *parent) : QDialog(parent) {
QLabel *labelA = new QLabel();
QLabel *labelB = new QLabel();
QLabel *labelC = new QLabel();
QLabel *labelD = new QLabel();
labelA->setStyleSheet("background-color:blue");
labelB->setStyleSheet("background-color:yellow");
labelC->setStyleSheet("background-color:purple");
labelD->setStyleSheet("background-color:green");
QGridLayout *layout = new QGridLayout(this);
layout->addWidget(labelA, 1, 1);
layout->addWidget(labelB, 1, 2);
layout->addWidget(labelC, 2, 1, 1, 2);
layout->addWidget(labelD, 3, 1, 1, 2);
}
I was incorrectly thinking that for expanding a row along 2 columns (the case of labelC and labelD) I had to write the corrdinates of the starting cell (2,1) the actual position and then the ending cell (2,2). I was misguided by a Java layout manager that worked exactly that way. Just for the record here you just have to indicate the total number of row span and column span which is 2 in my case.