1.无互动

QMessageBox::information(nullptr,"信息","登陆成功");

2.互动：确定、取消

QMessageBox::StandardButton box;
box = QMessageBox::question(this, "提示", "确定要添加吗?", QMessageBox::Yes|QMessageBox::No);
//取消
if(box==QMessageBox::No)return;
//确认
else if(box==QMessageBox::Yes){qDebug()<<"exit null score";}