问QLineEdit可见宽度设置？

EN

QHBoxLayout *nameRow = new QHBoxLayout; 

QLineEdit   *firstNameText = new QLineEdit,
            *middleIntText = new QLineEdit,
            *lastNameText = new QLineEdit;
//Whatever method is needed here to edit visible width
//firstNameText->???
//middleIntText->???
//lastNameText->???

nameRow->addWidget(firstNameText);
nameRow->addWidget(middleIntText);
nameRow->addWidget(lastNameText);

layout->addLayout(nameRow);

QWidget window;
window.setLayout(layout);
window.show();

firstNameText->setMaximumWidth(100);
firstNameText->setFixedWidth(120);

middleIntText->setMaximumWidth(50);
middleIntText->setFixedWidth(60);

lastNameText->setMaximumWidth(100);
lastNameText->setFixedWidth(120);