如何通过水平居中对齐QGroupBox中的QFormLayout

QGroupBox* groupBox = new QGroupBox("Group Box", this);

QFormLayout* formLayout = new QFormLayout(groupBox);

QLabel* label1 = new QLabel("Label 1:");
QLineEdit* lineEdit1 = new QLineEdit();

formLayout->addRow(label1, lineEdit1);

formLayout->setRowWrapPolicy(QFormLayout::WrapAllRows);
formLayout->setLabelAlignment(Qt::AlignRight);
formLayout->setFormAlignment(Qt::AlignHCenter | Qt::AlignTop);

QVBoxLayout* mainLayout = new QVBoxLayout(this);
mainLayout->addWidget(groupBox);