QT用程式碼對介面進行佈局時，按常規思路在tabwidget遇到一個很大的問題：就是最大化後有問題，沒有實現最大化的效果。

後來通過各種查詢最後又找到一種方法對tabwidget新增頁：

//.h檔案
class Data : public QMainWindow
{
    Q_OBJECT

public:
    Data(QWidget *parent = Q_NULLPTR);
private:
    Ui::DataClass ui;
    QTabWidget  *m_TabWidget;

    void initTabWidget();
};

class BackDataTab : public
 
 QWidget
{
    Q_OBJECT

public:
    explicit BackDataTab(QWidget *parent = 0);
public:
    const int m_EditHight;
    QLabel       *m_LabelFilterWidgetYMax,
                 *m_LabelFilterWidgetYMin,
                 *m_LabelFFTWidgetYMax;

    QLineEdit    *m_LineEditFilterWidgetYMax,
                 *
 
m_LineEditFilterWidgetYMin,
                 *m_LineEditFFTWidgetYMax,
                 *m_LineEditVideoPath;

    QCheckBox    *m_CheckBoxPass1,
                 *m_CheckBoxPass2,
                 *m_CheckBoxPass3,
                 *m_CheckBoxPass4;

    QPushButton  *m_PushBtnVideo;

    QGroupBox    *
 
m_GroupChioceShow,
                 *m_GroupChoicePass,
                 *m_GroupFilterAFFTYValue,
                 *m_GroupVideo;

    QRadioButton *m_RadioBtnFilter,
                 *m_RadioBtnNotch;

    QCustomPlot  *m_CustomFilter,
                 *m_CustomFFT;

    private slots:
    void slotBtnVideo();
    void slotCheckPass1();
    void slotCheckPass2();
    void slotCheckPass3();
    void slotCheckPass4();
private:
    QVector<int> m_VectCurPass;
    void ChoiceCheck();
    void initSignalSlot();
};

//.cpp檔案
Data::Data(QWidget *parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);
    // 顯示部分佈局
    m_TabWidget = new QTabWidget;
    m_TabWidget->addTab(new BackDataTab(), QString::fromLocal8Bit("資料回放"));

    setCentralWidget(m_TabWidget);
    setWindowState(Qt::WindowMaximized);
}

BackDataTab::BackDataTab(QWidget *parent /* = 0 */)
    :QWidget(parent)
    , m_EditHight(30)
{
    m_GroupVideo = new QGroupBox(QString::fromLocal8Bit("選擇要回放的錄影"));
    m_LineEditVideoPath = new QLineEdit();
    m_PushBtnVideo = new QPushButton(tr("..."));
    m_PushBtnVideo->setFixedWidth(m_EditHight);
    m_PushBtnVideo->setFixedHeight(m_EditHight);
    m_LineEditVideoPath->setFixedHeight(m_EditHight);
    m_LineEditVideoPath->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
    QHBoxLayout *HBLayoutVideo = new QHBoxLayout();
    HBLayoutVideo->addWidget(m_LineEditVideoPath);
    HBLayoutVideo->addWidget(m_PushBtnVideo);
    HBLayoutVideo->addSpacing(0);
    m_GroupVideo->setLayout(HBLayoutVideo);

    ...

    QHBoxLayout *HBLayoutTab = new QHBoxLayout();
    HBLayoutTab->addLayout(VBLayoutChartView);
    HBLayoutTab->addLayout(VBLayoutTab);
    HBLayoutTab->setStretchFactor(VBLayoutChartView, 8);
    HBLayoutTab->setStretchFactor(VBLayoutTab, 2);
    HBLayoutTab->setSpacing(0);      // 設定控制元件中元素間距
    setLayout(HBLayoutTab);
}

原來使用的另一種方式是：

QWidget *widgetBackData = new QWidget();
widgetBackData->setLayout(HBLayoutTab2);
m_TabWidget->addTab(widgetBackData, QString::fromLocal8Bit("資料回放"));
setCentralWidget(m_TabWidget);

這種的最大化的時候就會出現問題，問了一些大佬說，這種的是因為最頂層不是layout導致的，不是特別明白要怎麼做，有大佬懂得，歡迎指點。