Qt之Model-View架构（雨田哥的博客）

阅读原文时间：2023年07月15日阅读：1

*   [简述](http://blog.csdn.net/ly305750665/article/details/79016794#%E7%AE%80%E8%BF%B0)
*   [效果图](http://blog.csdn.net/ly305750665/article/details/79016794#%E6%95%88%E6%9E%9C%E5%9B%BE)
*   [代码](http://blog.csdn.net/ly305750665/article/details/79016794#%E4%BB%A3%E7%A0%81)
*   [结尾](http://blog.csdn.net/ly305750665/article/details/79016794#%E7%BB%93%E5%B0%BE)

简述

为什么会用这个模式，这里我就不解释了，可以看下豆子哥的见解。这里我只是如何去使用的。供大家共同探讨学习，主要是参考了Qt的Demo。

效果图

代码

//主代码界面QMvcTest.cpp
void QMvcTest::initControl()
{
    QCustomItemModel* customModel = new QCustomItemModel(QJsonArray(), ui.treeView);
    ItemDelegate *delegate = new ItemDelegate(ui.treeView);
    ui.treeView->setModel(customModel);
    delegate->setView(ui.treeView);
    ui.treeView->setAnimated(true);
    ui.treeView->setMouseTracking(true);
    ui.treeView->setItemDelegate(delegate);
    ui.treeView->setCursor(Qt::PointingHandCursor);

    const QModelIndex&& curIndex = customModel->index(0, 0).child(0, 0);
    ui.treeView->setCurrentIndex(curIndex);
    connect(delegate, SIGNAL(expanded(const QModelIndex &)), this, SLOT(onTreeViewExpanded(const QModelIndex &)));
}

void QMvcTest::onTreeViewExpanded(const QModelIndex &index)
{
    bool bExpanded = ui.treeView->isExpanded(index);
    if (!bExpanded)
    {
        ui.treeView->expand(index);
    }
    else
    {
        ui.treeView->collapse(index);
    }
}

//QCustomItemModel.cpp
QCustomItemModel::QCustomItemModel(const QJsonArray &data, QObject *parent)
: QAbstractItemModel(parent)
{
QJsonArray objChildArray = { QStringLiteral("雨田哥1号"), QStringLiteral("雨田哥2号"), QStringLiteral("雨田哥3号"), QStringLiteral("雨田哥4号"), QStringLiteral("雨田哥5号") };
QJsonObject obj{ { QStringLiteral("雨田哥"), objChildArray }
};
QJsonArray array = { obj, obj, obj };

QVector<QVariant> rootData;
rootData << "";
rootItem = new TreeItem(rootData);
setModelData(array);

}

QCustomItemModel::~QCustomItemModel()
{
delete rootItem;
}

int QCustomItemModel::columnCount(const QModelIndex & /* parent */) const
{
return rootItem->columnCount();
}

int QCustomItemModel::rowCount(const QModelIndex &parent) const
{
TreeItem *parentItem = getItem(parent);
return parentItem->childCount();
}

QVariant QCustomItemModel::data(const QModelIndex &index, int role) const
{
if (!index.isValid())
return QVariant();

TreeItem *item = getItem(index);
if (item == nullptr)
{
    return QVariant();
}

if (role == Qt::DisplayRole || role == Qt::EditRole)
{
    return item->data(index.column());
}
else if (role == Qt::UserRole + 1)
{
    //是否是子节点
    if (item->childCount() == 0)
    {
        return true;
    }
    return false;
}
else
{
    return QVariant();
}

}

Qt::ItemFlags QCustomItemModel::flags(const QModelIndex &index) const
{
if (!index.isValid())
return 0;
TreeItem *item = getItem(index);
if (item && item->childCount() > 0)
{
return Qt::NoItemFlags;
}
return Qt::ItemIsEditable | QAbstractItemModel::flags(index);
}

TreeItem *QCustomItemModel::getItem(const QModelIndex &index) const
{
if (index.isValid()) {
TreeItem *item = static_cast(index.internalPointer());
if (item)
return item;
}
return rootItem;
}

QVariant QCustomItemModel::headerData(int section, Qt::Orientation orientation, int role) const
{
if (orientation == Qt::Horizontal && role == Qt::DisplayRole)
return rootItem->data(section);

return QVariant();

}

QModelIndex QCustomItemModel::index(int row, int column, const QModelIndex &parent) const
{
if (parent.isValid() && parent.column() != 0)
return QModelIndex();
TreeItem *parentItem = getItem(parent);

TreeItem *childItem = parentItem->child(row);
if (childItem)
    return createIndex(row, column, childItem);
else
    return QModelIndex();

}

bool QCustomItemModel::insertColumns(int position, int columns, const QModelIndex &parent)
{
bool success;

beginInsertColumns(parent, position, position + columns - 1);
success = rootItem->insertColumns(position, columns);
endInsertColumns();

return success;

}

bool QCustomItemModel::insertRows(int position, int rows, const QModelIndex &parent)
{
TreeItem *parentItem = getItem(parent);
bool success;

beginInsertRows(parent, position, position + rows - 1);
success = parentItem->insertChildren(position, rows, rootItem->columnCount());
endInsertRows();

return success;

}

QModelIndex QCustomItemModel::parent(const QModelIndex &index) const
{
if (!index.isValid())
return QModelIndex();

TreeItem *childItem = getItem(index);
TreeItem *parentItem = childItem->parent();

if (parentItem == rootItem)
    return QModelIndex();

return createIndex(parentItem->childNumber(), 0, parentItem);

}

bool QCustomItemModel::removeColumns(int position, int columns, const QModelIndex &parent)
{
bool success;

beginRemoveColumns(parent, position, position + columns - 1);
success = rootItem->removeColumns(position, columns);
endRemoveColumns();

if (rootItem->columnCount() == 0)
    removeRows(0, rowCount());

return success;

}

bool QCustomItemModel::removeRows(int position, int rows, const QModelIndex &parent)
{
TreeItem *parentItem = getItem(parent);
bool success = true;

beginRemoveRows(parent, position, position + rows - 1);
success = parentItem->removeChildren(position, rows);
endRemoveRows();

return success;

}

bool QCustomItemModel::setData(const QModelIndex &index, const QVariant &value, int role)
{
if (role == Qt::EditRole)
{
TreeItem *item = getItem(index);
bool result = item->setData(index.column(), value);

    if (result)
        emit dataChanged(index, index);
    return result;
}
else if (role == Qt::FontRole)
{
    TreeItem *item = getItem(index);
    if (item && item->childCount() == 0)
    {
        item->m_itemFontIsBold = value.toBool();
    }
    return true;
}
else
{
    return false;
}

}

bool QCustomItemModel::setHeaderData(int section, Qt::Orientation orientation,
const QVariant &value, int role)
{
if (role != Qt::EditRole || orientation != Qt::Horizontal)
return false;

bool result = rootItem->setData(section, value);

if (result)
    emit headerDataChanged(orientation, section, section);

return result;

}

void QCustomItemModel::setModelData(const QJsonArray &data)
{
for (int nRootIndex = 0; nRootIndex < data.size(); nRootIndex++)
{
const QJsonObject&& obj = data.at(nRootIndex).toObject();
for (auto itor = obj.begin(); itor != obj.end(); itor++)
{
const QString&& key = itor.key();
const QJsonArray&& childAray = itor.value().toArray();

        QVector<QVariant> columnData;
        columnData << key;
        rootItem->insertChildren(nRootIndex, 1, rootItem->columnCount());    TreeItem* parent = rootItem-&gt;child(nRootIndex);
    parent-&gt;setData(0, key);

    for (int index = 0; index &lt; childAray.size(); index++)
    {
        parent-&gt;insertChildren(index, 1, rootItem-&gt;columnCount());
        parent-&gt;child(index)-&gt;setData(0, childAray.at(index).toString());
    }
}
}

}

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//TreeItem.cpp
TreeItem::TreeItem(const QVector &data, TreeItem *parent)
{
m_itemFontIsBold = true;
parentItem = parent;
itemData = data;
}

TreeItem::~TreeItem()
{
qDeleteAll(childItems);
}

TreeItem *TreeItem::child(int number)
{
return childItems.value(number);
}

int TreeItem::childCount() const
{
return childItems.count();
}

int TreeItem::childNumber() const
{
if (parentItem)
return parentItem->childItems.indexOf(const_cast(this));
```
return 0;
```
}

int TreeItem::columnCount() const
{
return itemData.count();
}

QVariant TreeItem::data(int column) const
{
return itemData.value(column);
}

bool TreeItem::insertChildren(int position, int count, int columns)
{
if (position < 0 || position > childItems.size())
return false;
```
for (int row = 0; row < count; ++row) {
    QVector<QVariant> data(columns);
    TreeItem *item = new TreeItem(data, this);
    childItems.insert(position, item);
}

return true;
```
}

bool TreeItem::insertColumns(int position, int columns)
{
if (position < 0 || position > itemData.size())
return false;
```
for (int column = 0; column < columns; ++column)
    itemData.insert(position, QVariant());

foreach (TreeItem *child, childItems)
    child->insertColumns(position, columns);

return true;
```
}

TreeItem *TreeItem::parent()
{
return parentItem;
}

bool TreeItem::removeChildren(int position, int count)
{
if (position < 0 || position + count > childItems.size())
return false;
```
for (int row = 0; row < count; ++row)
    delete childItems.takeAt(position);

return true;
```
}

bool TreeItem::removeColumns(int position, int columns)
{
if (position < 0 || position + columns > itemData.size())
return false;
```
for (int column = 0; column < columns; ++column)
    itemData.remove(position);

foreach (TreeItem *child, childItems)
    child->removeColumns(position, columns);

return true;
```
}

bool TreeItem::setData(int column, const QVariant &value)
{
if (column < 0 || column >= itemData.size())
return false;
```
itemData[column] = value;
return true;
```
}
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//ItemDelegate.cpp
void ItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QStyleOptionViewItem viewOption(option);
QStyledItemDelegate::paint(painter, viewOption, index);
```
bool bExpanded = false;
if (m_treeView != NULL)
{
    const QAbstractItemModel *model = index.model();
    if (!model->hasChildren(index))
    {
        return;
    }
    bExpanded = m_treeView->isExpanded(index);
}

QPixmap pixmap = bExpanded ? QPixmap(m_expandIconName) : QPixmap(m_collapseIconName);
QRect decorationRect = QRect(viewOption.rect.left() + 14, viewOption.rect.top() + 12, m_pixmapHeight, m_pixmapWidth);
painter->drawPixmap(decorationRect, pixmap);
```
}

bool ItemDelegate::editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index)
{
if (event->type() == QEvent::MouseButtonPress && Qt::LeftButton == qApp->mouseButtons())
{
m_treeView->update();
emit expanded(index);
}
return QStyledItemDelegate::editorEvent(event, model, option, index);
}

void ItemDelegate::setView(QTreeView *treeView)
{
m_treeView = treeView;
}
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//QSS样式
QTreeView
{
background-color: #ffffff;
show-decoration-selected: 1;
outline:0px;
}

QTreeView::item {
background-color:transparent;
font-family: Microsoft YaHei;
font-size: 12px;
color: #666666;
text-align:left;
height:32px;
padding-left:22px;
}

QTreeView::item:has-children {
background-color:transparent;
font-family: Microsoft YaHei;
font-size: 12px;
color: #333333;
text-align:left;
height:32px;
padding-left:22px;
}

QTreeView::item:hover,QTreeView::item:selected {
background-color:#D3EFFF;
font-size: 12px;
color: #00A1FF;
border:0px;
text-align:left;
}

QTreeView::branch:has-children:!has-siblings:closed,
QTreeView::branch:closed:has-children:has-siblings {
border-image: none;
image: url(:/QMvcTest/Resources/smallPackup.png:);
}

QTreeView::branch:open:has-children:!has-siblings,
QTreeView::branch:open:has-children:has-siblings {
border-image: none;
image: url(:/QMvcTest/Resources/smallExp.png);
}
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