Qt5のQWidgetでsetFixedHeight()は使わず、自身に内包するウィジェットの高さを合計した高さに自動調整して欲しい

AbstractPanel.cpp

#include <QDebug>

#include "AbstractPanel.h"


AbstractPanel::AbstractPanel(QWidget *parent) : QAbstractItemView(parent)
{
}


QRect AbstractPanel::visualRect(const QModelIndex &index) const
{
    Q_UNUSED(index);
    return QRect(0, 0, 300, 200);
}

void AbstractPanel::scrollTo(const QModelIndex &index, ScrollHint hint)
{
    Q_UNUSED(index);
    Q_UNUSED(hint);
}

QModelIndex AbstractPanel::indexAt(const QPoint &point) const
{
    Q_UNUSED(point);
    return QModelIndex();
}

QModelIndex AbstractPanel::moveCursor(CursorAction cursorAction, Qt::KeyboardModifiers modifiers)
{
    Q_UNUSED(cursorAction);
    Q_UNUSED(modifiers);
    return QModelIndex();
}

int AbstractPanel::horizontalOffset() const
{
    return 0;
}

int AbstractPanel::verticalOffset() const
{
    return 0;
}

bool AbstractPanel::isIndexHidden(const QModelIndex &index) const
{
    Q_UNUSED(index)
    return false;
}

void AbstractPanel::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
    Q_UNUSED(rect);
    Q_UNUSED(command);
}

QRegion AbstractPanel::visualRegionForSelection(const QItemSelection &selection) const
{
    Q_UNUSED(selection);
    return QRegion();
}

void AbstractPanel::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles)
{
    Q_UNUSED(bottomRight);
    Q_UNUSED(roles);
    //モデルからデータを取得し、表示内容を更新する.
    updateView(topLeft, model()->data(topLeft));
}

AbstractPanel.h

#pragma once

#include <QAbstractItemView>

class AbstractPanel : public QAbstractItemView
{
Q_OBJECT
public:
    explicit AbstractPanel(QWidget *parent = nullptr);

    QRect visualRect(const QModelIndex &index) const override;
    void scrollTo(const QModelIndex &index, ScrollHint hint) override;
    QModelIndex indexAt(const QPoint &point) const override;

    virtual void updateView(const QModelIndex &index, const QVariant& data) = 0;

protected slots:

    void dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles) override;

protected:
    QModelIndex moveCursor(CursorAction cursorAction, Qt::KeyboardModifiers modifiers) override;
    int horizontalOffset() const override;
    int verticalOffset() const override;
    bool isIndexHidden(const QModelIndex &index) const override;
    void setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command) override;
    QRegion visualRegionForSelection(const QItemSelection &selection) const override;
};

CMakeLists.txt

set(EXAMPLE_NAME groupbox03)

file(GLOB SOURCES *.cpp)
file(GLOB HEADERS *.h)

add_definitions(${Qt5Core_DEFINITIONS})
add_definitions(${Qt5Widgets_DEFINITIONS})
add_definitions(${Qt5Gui_DEFINITIONS})

list(APPEND CMAKE_CXX_FLAGS "${Qt5Core_EXECUTABLE_COMPILE_FLAGS}")
list(APPEND CMAKE_CXX_FLAGS "${Qt5Widgets_EXECUTABLE_COMPILE_FLAGS}")
list(APPEND CMAKE_CXX_FLAGS "${Qt5Gui_EXECUTABLE_COMPILE_FLAGS}")

add_executable(${EXAMPLE_NAME}
    ${SOURCES}
    ${HEADERS}
    )

target_include_directories(${EXAMPLE_NAME} PRIVATE
    ${Qt5Core_INCLUDES}
    ${Qt5Widgets_INCLUDES}
    ${Qt5Gui_INCLUDES}
    )

target_link_libraries(${EXAMPLE_NAME} PRIVATE
    ${Qt5Core_LIBRARIES}
    ${Qt5Widgets_LIBRARIES}
    ${Qt5Gui_LIBRARIES}
    )

main.cpp

#include <QApplication>
#include <QFile>
#include <QDebug>

#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QFile File("style.qss");
    if (File.open(QFile::ReadOnly))
    {
        QString StyleSheet = QLatin1String(File.readAll());
        a.setStyleSheet(StyleSheet);
    }
    else {
        qWarning() << "style.qss not found.";
    }

    MainWindow w;
    w.show();

    return a.exec();
}

mainwindow.cpp

#include <QDebug>
#include <QVBoxLayout>
#include <QTableWidget>
#include <QHeaderView>
#include <QPushButton>
#include <QHBoxLayout>
#include <QLabel>
#include <QComboBox>
#include <QTableView>
#include <QStandardItemModel>
#include <QSizePolicy>
#include <QGroupBox>

#include "mainwindow.h"
#include "SubPanel.h"

MainWindow::MainWindow(QWidget *parent) :
    QWidget(parent)
{

    auto mainLayout = new QVBoxLayout(this);
    {
        auto layoutTop = new QHBoxLayout;
        {
            auto button = new QPushButton("top", this);
            layoutTop->addWidget(button);

            auto comboBox = new QComboBox(this);
            layoutTop->addWidget(comboBox);
        }
        mainLayout->addLayout(layoutTop);

        auto layoutMiddle = new QHBoxLayout;
        {
            auto layoutLeft = new QVBoxLayout;
            {
                auto button = new QPushButton("middle left", this);
                layoutLeft->addWidget(button);

                auto group1 = new QGroupBox("GroupBox 1");
                {
                    auto layout = new QVBoxLayout;
                    {
                        auto button1 = new QPushButton("middle left groupbox1", this);
                        layout->addWidget(button1);
                    }
                    group1->setLayout(layout);
                }
                layoutLeft->addWidget(group1);

                auto group2 = new QGroupBox("GroupBox 2");
                {
                    auto layout = new QVBoxLayout;
                    {
                        auto button1 = new QPushButton("middle left groupbox2", this);
                        layout->addWidget(button1);
                    }
                    group2->setLayout(layout);
                }
                layoutLeft->addWidget(group2);
            }
            layoutMiddle->addLayout(layoutLeft);

            auto layoutRight = new QVBoxLayout;
            {
                auto button = new QPushButton("middle right", this);
                layoutRight->addWidget(button);
            }
            layoutMiddle->addLayout(layoutRight);
        }
        mainLayout->addLayout(layoutMiddle);

        auto layoutBottom = new QVBoxLayout;
        {
/*
 * QFrame派生であっても、妙な間を作らずぴったりとした高さにしたい
 */
#if defined(NOT_AS_EXPECTED)
            auto sub = new SubPanel(this);
            layoutBottom->addWidget(sub, 0, Qt::AlignTop);

            layoutBottom->setSizeConstraint(QLayout::SetFixedSize);
#else
            auto button = new QPushButton("middle bottom", this);
            layoutBottom->addWidget(button);

            auto table = new QTableWidget(this);
            {
                table->setStyleSheet("background-color: Blue;");
                table->setColumnCount(3);
                table->setRowCount(3);
                table->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
                table->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
                auto h = table->horizontalHeader();
                h->setSectionResizeMode(0, QHeaderView::Stretch);
                h->setSectionResizeMode(1, QHeaderView::Stretch);
                h->setSectionResizeMode(2, QHeaderView::Stretch);
                table->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
                table->resizeRowsToContents();

                int nRowHeight = table->rowHeight(0);
                int nTableHeight =
                    (table->rowCount() * nRowHeight) +
                    table->horizontalHeader()->height() +
                    2 * table->frameWidth();
                table->setMinimumHeight(nTableHeight);
                table->setMaximumHeight(nTableHeight);
            }
#endif
        }
        mainLayout->addLayout(layoutBottom);

        setLayout(mainLayout);

        mainLayout->addStretch();
    }

    adjustSize();

}

mainwindow.h

#pragma once

#include <QWidget>

class MainWindow : public QWidget
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow() override = default;

private:
};

SubPanel.cpp

#include <QDebug>
#include <QWidget>
#include <QDebug>
#include <QGroupBox>
#include <QLabel>
#include <QComboBox>
#include <QTableWidget>
#include <QTableWidgetItem>
#include <QHeaderView>

#include "SubPanel.h"

SubPanel::SubPanel(QWidget *parent)
    : AbstractPanel(parent)
{
    auto layout = new QVBoxLayout(this);
    {
        auto button = new QPushButton("middle bottom", this);
        layout->addWidget(button, 1, Qt::AlignTop);

        auto table = new QTableWidget(this);
        {
            table->setStyleSheet("background-color: Blue;");
            table->setColumnCount(3);
            table->setRowCount(3);
            table->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
            table->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
            auto h = table->horizontalHeader();
            h->setSectionResizeMode(0, QHeaderView::Stretch);
            h->setSectionResizeMode(1, QHeaderView::Stretch);
            h->setSectionResizeMode(2, QHeaderView::Stretch);
            table->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
            table->resizeRowsToContents();

            int nRowHeight = table->rowHeight(0);
            int nTableHeight =
                (table->rowCount() * nRowHeight) +
                table->horizontalHeader()->height() +
                2 * table->frameWidth();
            table->setMinimumHeight(nTableHeight);
            table->setMaximumHeight(nTableHeight);
        }
        layout->addWidget(table, 1, Qt::AlignTop);
    }

    setLayout(layout);      // 主レイアウトに設定する

//    layout->setSizeConstraint(QLayout::SetFixedSize);

//    setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding);

//    setFixedHeight(100);
}

/*
 *
 */
SubPanel::~SubPanel()
= default;

void SubPanel::initialize()
{
}

void SubPanel::updateView(const QModelIndex &index, const QVariant &data)
{
    switch (index.row()) {
        case 0:
            switch (index.column()) {
                case 0: {
                    break;
                }
                default:
                    break;
            }
            break;
        default:
            break;
    }
}

SubPanel.h

#pragma once

#include <QObject>
#include <QCloseEvent>
#include <QLabel>
#include <QPushButton>
#include <QHBoxLayout>

#include "AbstractPanel.h"


class SubPanel : public AbstractPanel
{
Q_OBJECT

    friend class TestQzmPanel12;

public:
    explicit SubPanel(QWidget *parent = nullptr);

    ~SubPanel() override;

    void initialize();

    void updateView(const QModelIndex &index, const QVariant &data) override;

private slots:


private:

};