为什么 QT 中的布局管理器不起作用？

Question

 this->setWindowTitle(tr("数据转移程序"));
 edt_ftp_server = new QLineEdit;
 edt_ftp_port = new QLineEdit;
 edt_ftp_account = new QLineEdit;
 edt_ftp_pwd = new QLineEdit;
 edt_ftp_pwd->setEchoMode( QLineEdit::Password );

 lbl_ftp_server = new QLabel;
 lbl_ftp_server->setText(tr("FTP服务器地址："));
 lbl_ftp_server->setBuddy( edt_ftp_server );

 lbl_ftp_port = new QLabel;
 lbl_ftp_port->setText(tr("FTP服务器端口："));
 lbl_ftp_port->setBuddy( edt_ftp_port );

 lbl_ftp_account = new QLabel;
 lbl_ftp_account->setText(tr("FTP登录帐号："));
 lbl_ftp_account->setBuddy( edt_ftp_account );

 lbl_ftp_pwd = new QLabel;
 lbl_ftp_pwd->setText(tr("FTP登录密码："));
 lbl_ftp_pwd->setBuddy( edt_ftp_pwd );

 ftp_settings = new QGroupBox(this);
 ftp_settings->setTitle(tr("FTP服务器设置"));
 ftp_settingsLayout = new QGridLayout;
 ftp_settingsLayout->addWidget( lbl_ftp_server, 0, 0);
 ftp_settingsLayout->addWidget( edt_ftp_server, 0, 1);
 ftp_settingsLayout->addWidget( lbl_ftp_port, 1, 0);
 ftp_settingsLayout->addWidget( edt_ftp_port, 1, 1);
 ftp_settingsLayout->addWidget( lbl_ftp_account, 2, 0);
 ftp_settingsLayout->addWidget( edt_ftp_account, 2, 1);
 ftp_settingsLayout->addWidget( lbl_ftp_pwd, 3, 0);
 ftp_settingsLayout->addWidget( edt_ftp_pwd, 3, 1);

 ftp_settings->setLayout( ftp_settingsLayout );

 edt_db_server = new QLineEdit( this );
 edt_db_port = new QLineEdit( this );
 edt_db_account = new QLineEdit( this );
 edt_db_pwd = new QLineEdit( this );
 edt_db_pwd->setEchoMode( QLineEdit::Password );

 lbl_db_server = new QLabel( this );
 lbl_db_server->setText(tr("FTP服务器地址："));
 lbl_db_server->setBuddy( edt_ftp_server );

 lbl_db_port = new QLabel( this );
 lbl_db_port->setText(tr("FTP服务器端口："));
 lbl_db_port->setBuddy( edt_ftp_port );

 lbl_db_account = new QLabel( this );
 lbl_db_account->setText(tr("FTP登录帐号："));
 lbl_db_account->setBuddy( edt_ftp_account );

 lbl_db_pwd = new QLabel( this );
 lbl_db_pwd->setText(tr("FTP登录密码"));
 lbl_db_pwd->setBuddy( edt_ftp_pwd );

 db_settings = new QGroupBox(this);
 db_settings->setTitle(tr("数据库服务器设置"));
 db_settingsLayout = new QGridLayout;
 db_settingsLayout->addWidget( lbl_ftp_server, 0, 0);
 db_settingsLayout->addWidget( edt_ftp_server, 0, 1);
 db_settingsLayout->addWidget( lbl_ftp_port,1, 0);
 db_settingsLayout->addWidget( edt_ftp_port,1, 1);
 db_settingsLayout->addWidget( lbl_ftp_account, 2, 0);
 db_settingsLayout->addWidget( edt_ftp_account, 2, 1);
 db_settingsLayout->addWidget( lbl_ftp_pwd,3, 0);
 db_settingsLayout->addWidget( edt_ftp_pwd, 3, 1);

 db_settings->setLayout( db_settingsLayout );

 buttonsLayout = new QHBoxLayout;
 buttonsLayout->addStretch();

 btn_start = new QPushButton;
 btn_start->setText(tr("开始"));
 buttonsLayout->addWidget(btn_start);

 btn_stop = new QPushButton;
 btn_stop->setText(tr("停止"));
 buttonsLayout->addWidget( btn_stop );

 btn_exit = new QPushButton;
 btn_exit->setText(tr("退出"));
 buttonsLayout->addWidget(btn_exit);

 settingLayout = new QVBoxLayout;
 settingLayout->addWidget( db_settings );
 settingLayout->addStretch();
 settingLayout->addWidget( ftp_settings );

 centralLayout = new QHBoxLayout;
 centralLayout->addLayout( settingLayout );
 lst_log = new QListWidget;
 centralLayout->addWidget(lst_log);

 winLayout = new QVBoxLayout;
 winLayout->addLayout( centralLayout );
 winLayout->addLayout( buttonsLayout );
 setLayout( winLayout );

我正在开发一个小型的 qt 程序，并在 QMainWindow 子类构造函数中编写了上面的代码。 但显示的小部件很混乱。感谢所有建议！

以下是结果截图：

Answer 1

我怀疑问题出在顶层布局，即winLayout。将 QMainWindow 的中央小部件设置为 winLayout 的父级：

winLayout = new QVBoxLayout(ui->centralWidget);

我建议使用 Qt Creator 或 Qt Designer 来设计用户界面。 Qt Creator 为布局和其他无趣的事情创建必要的代码。即使您决定通过编写自己的代码来创建用户界面，您也可以使用 Qt Creator 创建原型并查看它创建的代码类型。