QHBoxLayout *cbl = new QHBoxLayout;
    cbl->setContentsMargins(0, 0, 0, 0);
    cbl->setSpacing(0);
    cbl->addWidget(new QLabel("Label"));
    cbl->addWidget(new QLabel("Label"));
    cbl->addWidget(new QLabel("Label"));
    cbl->addStretch();///////////////////////////////////////////////////////用这个