Qt QTreeWidget 固定第一列

Qt 有一个demo "Frozen Column Example"是QTableView固定第一列，我仿照着写了一个QTreeWidget固定第一列。

头文件 “QFrozenTreeWidget.h”

#ifndef QFROZENTREEWIDGET_H

#define QFROZENTREEWIDGET_H

#include 

#include 

#include 

//定位结构体，用来存储 展合、勾选 的item位置

struct structIndex

{

    int m_index;

    structIndex *m_pChildIndex;

    structIndex()

    {

        m_index = -1;

        m_pChildIndex = NULL;

    }

};

class QFrozenTreeWidget : public QTreeWidget

{

    Q_OBJECT

public:

    QFrozenTreeWidget(QWidget *parent = 0);

    ~QFrozenTreeWidget();

    //接口

public:

    void SetFrozenColumnHeader(const QString &strHeader);

    void CreateNewItem(QTreeWidgetItem *item);

protected:

    void resizeEvent(QResizeEvent *event);

    QModelIndex moveCursor(CursorAction cursorAction, Qt::KeyboardModifiers modifiers);

    void scrollTo(const QModelIndex &index, ScrollHint hint);

private:

    void Init();

    void UpdateFrozenTreeGeometry();

    /*

     * 用来 从 固定列和本树 找对应的item

     * 比如 固定列某个item展开,要找到本树的对应位置item让其展开，实现同步

     * 下面是递归方法

     * 可能还有简单方法，比如：

     * 可以根据 鼠标位置 找到对应item,用itemAt(QPoint);

     * 可以根据 item 对应的QModelIndex 里row() 采用加法找到对应item，有兴趣的可以实现试试

     */

    structIndex *GetItemIndex(QTreeWidgetItem *targetItem, QTreeWidgetItem *sourceItem);

    QTreeWidgetItem *GetItemFromIndex(QTreeWidgetItem *item, structIndex *index);

    QTreeWidgetItem *GetItemFromItem(QTreeWidget *targetTree, QTreeWidgetItem *souceItem);

    /*

     * 下面实现同步勾选

     */

    void SetParentCheckState(QTreeWidgetItem *parentItem);

    void SetChildCheckState(QTreeWidgetItem *selfItem);

    void SetItemChecked(QTreeWidgetItem *item);

private slots:

    void OnItemCollapsed(QTreeWidgetItem *item);

    void OnItemExpanded(QTreeWidgetItem *item);

    void OnItemChanged(QTreeWidgetItem *item, int column);

    void UpdateSectionWidthSlot(int logicalIndex, int, int newSize);

private:

    QTreeWidget *m_pFrozenTreeWidget;   //固定的第一列，覆盖在本树第一列位置，实现第一列保持不动

};

#endif // QFROZENTREEWIDGET_H

cpp文件 "QFrozenTreeWidget.cpp"

#include 

#include 

#include "QFrozenTreeWidget.h"

QFrozenTreeWidget::QFrozenTreeWidget(QWidget *parent)

    : QTreeWidget(parent)

{

    Init();

}

QFrozenTreeWidget::~QFrozenTreeWidget()

{

}

void QFrozenTreeWidget::SetFrozenColumnHeader(const QString &strHeader)

{

    m_pFrozenTreeWidget->setHeaderLabel(strHeader);

}

void QFrozenTreeWidget::resizeEvent(QResizeEvent *event)

{

    QTreeWidget::resizeEvent(event);

    UpdateFrozenTreeGeometry();

}

QModelIndex QFrozenTreeWidget::moveCursor(QAbstractItemView::CursorAction cursorAction, Qt::KeyboardModifiers modifiers)

{

    QModelIndex current = QTreeWidget::moveCursor(cursorAction, modifiers);

    if (cursorAction == MoveLeft && current.column() > 0

            && visualRect(current).topLeft().x() < m_pFrozenTreeWidget->columnWidth(0))

    {

        const int newValue = horizontalScrollBar()->value() + visualRect(current).topLeft().x()

                - m_pFrozenTreeWidget->columnWidth(0);

        horizontalScrollBar()->setValue(newValue);

    }

    return current;

}

void QFrozenTreeWidget::scrollTo(const QModelIndex &index, QAbstractItemView::ScrollHint hint)

{

    if (index.column() > 0)

    {

        QTreeWidget::scrollTo(index, hint);

    }

}

void QFrozenTreeWidget::Init()

{

    m_pFrozenTreeWidget = new QTreeWidget(this);

    m_pFrozenTreeWidget->setFocusPolicy(Qt::NoFocus);

    //让固定列宽度不能手动调整大小，而跟随本树第一列大小来改变

    m_pFrozenTreeWidget->header()->setSectionResizeMode(QHeaderView::Fixed);

    //让浮在本树上边而不是下边

    viewport()->stackUnder(m_pFrozenTreeWidget);

    //设置第一列背景颜色好显示效果

    m_pFrozenTreeWidget->setStyleSheet("QTreeView { border: none;"

                                       "background-color: #8ede21;"

                                       "selection-background-color: #999 }");

    //设置选择模式一样

    m_pFrozenTreeWidget->setSelectionModel(selectionModel());

    //设置第一列宽度一样

    m_pFrozenTreeWidget->setColumnWidth(0, columnWidth(0));

    //固定列不需要水平垂直滚动条，用本列的来控制

    m_pFrozenTreeWidget->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

    m_pFrozenTreeWidget->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

    m_pFrozenTreeWidget->show();

    //设置滚动条模式按像素为单位滚动

    setHorizontalScrollMode(ScrollPerPixel);

    setVerticalScrollMode(ScrollPerPixel);

    m_pFrozenTreeWidget->setVerticalScrollMode(ScrollPerPixel);

    connect(header(), SIGNAL(sectionResized(int,int,int)), this, SLOT(UpdateSectionWidthSlot(int,int,int)));

    //连接垂直滚动条的信号槽实现同步滚动

    connect(m_pFrozenTreeWidget->verticalScrollBar(), SIGNAL(valueChanged(int)), verticalScrollBar(), SLOT(setValue(int)));

    connect(verticalScrollBar(), SIGNAL(valueChanged(int)), m_pFrozenTreeWidget->verticalScrollBar(), SLOT(setValue(int)));

    //item 展合

    connect(m_pFrozenTreeWidget, SIGNAL(itemCollapsed(QTreeWidgetItem*)), this, SLOT(OnItemCollapsed(QTreeWidgetItem*)));

    connect(m_pFrozenTreeWidget, SIGNAL(itemExpanded(QTreeWidgetItem*)), this, SLOT(OnItemExpanded(QTreeWidgetItem*)));

    //第一列item勾选

    connect(m_pFrozenTreeWidget, SIGNAL(itemChanged(QTreeWidgetItem*,int)), this, SLOT(OnItemChanged(QTreeWidgetItem*,int)));

}

void QFrozenTreeWidget::UpdateFrozenTreeGeometry()

{

    m_pFrozenTreeWidget->setGeometry(frameWidth(), frameWidth(), columnWidth(0), viewport()->height() + header()->height());

}

structIndex *QFrozenTreeWidget::GetItemIndex(QTreeWidgetItem *targetItem, QTreeWidgetItem *sourceItem)

{

    if (targetItem == sourceItem)

    {

        return new structIndex;

    }

    for (int i = 0; i < targetItem->childCount(); ++i)

    {

        structIndex *pChildStructIndex = GetItemIndex(targetItem->child(i), sourceItem);

        if (pChildStructIndex != NULL)

        {

            structIndex *pStructIndex = new structIndex;

            pStructIndex->m_pChildIndex = pChildStructIndex;

            pStructIndex->m_index = i;

            return pStructIndex;

        }

    }

    return NULL;

}

QTreeWidgetItem *QFrozenTreeWidget::GetItemFromIndex(QTreeWidgetItem *item, structIndex *index)

{

    if (index->m_index == -1)

    {

        return item;

    }

    QTreeWidgetItem *targetItem = GetItemFromIndex(item->child(index->m_index), index->m_pChildIndex);

    if (index->m_pChildIndex != NULL)

    {

        delete index->m_pChildIndex;

        index->m_pChildIndex = NULL;

    }

    return targetItem;

}

QTreeWidgetItem *QFrozenTreeWidget::GetItemFromItem(QTreeWidget *targetTree, QTreeWidgetItem *souceItem)

{

    structIndex *pStructIndex = GetItemIndex(souceItem->treeWidget()->invisibleRootItem(), souceItem);

    QTreeWidgetItem *item = GetItemFromIndex(targetTree->invisibleRootItem(), pStructIndex);

    delete pStructIndex;

    return item;

}

void QFrozenTreeWidget::SetParentCheckState(QTreeWidgetItem *parentItem)

{

    if (parentItem == NULL)

    {

        return;

    }

    int count = 0;

    for (int i = 0; i < parentItem->childCount(); ++i)

    {

        if (parentItem->child(i)->checkState(0) == Qt::Checked)

        {

            count++;

        }

    }

    if (count == parentItem->childCount())

    {

        parentItem->setCheckState(0, Qt::Checked);

    }

    else

    {

        parentItem->setCheckState(0, Qt::Unchecked);

    }

    GetItemFromItem(this, parentItem)->setCheckState(0, parentItem->checkState(0));

    SetParentCheckState(parentItem->parent());

}

void QFrozenTreeWidget::SetChildCheckState(QTreeWidgetItem *selfItem)

{

    for (int i = 0; i < selfItem->childCount(); ++i)

    {

        selfItem->child(i)->setCheckState(0, selfItem->checkState(0));

        GetItemFromItem(this, selfItem->child(i))->setCheckState(0, selfItem->checkState(0));

        SetChildCheckState(selfItem->child(i));

    }

}

void QFrozenTreeWidget::SetItemChecked(QTreeWidgetItem *item)

{

    QTreeWidgetItem *targetItem = GetItemFromItem(m_pFrozenTreeWidget, item);

    targetItem->setCheckState(0, item->checkState(0));

}

void QFrozenTreeWidget::CreateNewItem(QTreeWidgetItem *item)

{

    QTreeWidgetItem *newItem = NULL;

    if (item->parent() == NULL)

    {

        newItem = new QTreeWidgetItem(GetItemFromItem(m_pFrozenTreeWidget, m_pFrozenTreeWidget->invisibleRootItem()));

    }

    else

    {

        newItem = new QTreeWidgetItem(GetItemFromItem(m_pFrozenTreeWidget, item->parent()));

    }

    newItem->setCheckState(0, Qt::Unchecked);

    newItem->setText(0, item->text(0));

}

void QFrozenTreeWidget::OnItemCollapsed(QTreeWidgetItem *item)

{

    collapseItem(GetItemFromItem(this, item));

}

void QFrozenTreeWidget::OnItemExpanded(QTreeWidgetItem *item)

{

    expandItem(GetItemFromItem(this, item));

}

void QFrozenTreeWidget::OnItemChanged(QTreeWidgetItem *item, int column)

{

    GetItemFromItem(this, item)->setCheckState(column, item->checkState(column));

    m_pFrozenTreeWidget->blockSignals(true);

    SetChildCheckState(item);

    SetParentCheckState(item->parent());

    m_pFrozenTreeWidget->blockSignals(false);

}

void QFrozenTreeWidget::UpdateSectionWidthSlot(int logicalIndex, int, int newSize)

{

    if (logicalIndex == 0)

    {

        m_pFrozenTreeWidget->setColumnWidth(0, newSize);

        UpdateFrozenTreeGeometry();

    }

}

"main.cpp"

#include "QFrozenTreeWidget.h"

#include 

int main(int argc, char *argv[])

{

    QApplication a(argc, argv);

    QFrozenTreeWidget w;

    w.setColumnCount(5);

    w.setHeaderLabels(QStringList() << "A" << "B" << "C" << "D" << "E");

    w.SetFrozenColumnHeader("A");

    for (int i = 0; i < 5; ++i)

    {

        QTreeWidgetItem *parent = new QTreeWidgetItem(w.invisibleRootItem(), QStringList() << QString("%1a").arg(i) << QString("%1b").arg(i) << QString("%1c").arg(i) << QString("%1d").arg(i) << QString("%1e").arg(i));

        w.CreateNewItem(parent);

        for (int j = 0; j < 5; ++j)

        {

            QTreeWidgetItem *child = new QTreeWidgetItem(parent,

                                        QStringList() << QString("a%1%2").arg(i).arg(j)

                                        << QString("b%1%2").arg(i).arg(j)

                                        << QString("c%1%2").arg(i).arg(j)

                                        << QString("d%1%2").arg(i).arg(j)

                                        << QString("e%1%2").arg(i).arg(j));

            w.CreateNewItem(child);

        }

    }

    w.resize(400, 300);

    w.setColumnWidth(0, 100);

    w.show();

    return a.exec();

}