表示一行字符串数据
treeitem.h
#ifndef TREEITEM_H
#define TREEITEM_H
#include
#include
//! [0]
class TreeItem
{
public:
explicit TreeItem(const QList<QVariant> &data, TreeItem *parentItem = 0);
~TreeItem();
void appendChild(TreeItem *child);
TreeItem *child(int row);
int childCount() const;
int columnCount() const;
QVariant data(int column) const;
int row() const;
TreeItem *parentItem();
private:
QList<TreeItem*> m_childItems;
QList<QVariant> m_itemData;
TreeItem *m_parentItem;
};
//! [0]
#endif // TREEITEM_H
treeitem.cpp
/*
treeitem.cpp
A container for items of data supplied by the simple tree model.
*/
#include
#include "treeitem.h"
//! [0] 当前项数据data,父项parent
TreeItem::TreeItem(const QList<QVariant> &data, TreeItem *parent)
{
m_parentItem = parent;
m_itemData = data;
}
//! [0]
//! [1]
TreeItem::~TreeItem()
{
qDeleteAll(m_childItems);
}
//! [1]
//! [2] 添加子项
void TreeItem::appendChild(TreeItem *item)
{
m_childItems.append(item);
}
//! [2]
//! [3] 子项,通过行索引返回
TreeItem *TreeItem::child(int row)
{
return m_childItems.value(row);
}
//! [3]
//! [4] 子项数
int TreeItem::childCount() const
{
return m_childItems.count();
}
//! [4]
//! [5] 列数
int TreeItem::columnCount() const
{
return m_itemData.count();
}
//! [5]
//! [6] 列数据,索引每一列的字符串单词
QVariant TreeItem::data(int column) const
{
return m_itemData.value(column);
}
//! [6]
//! [7] 父项
TreeItem *TreeItem::parentItem()
{
return m_parentItem;
}
//! [7]
//! [8] 默认返回0行,代表Item 只是1项
int TreeItem::row() const
{
if (m_parentItem)
return m_parentItem->m_childItems.indexOf(const_cast<TreeItem*>(this));
return 0;
}
//! [8]
树模型
treemodel.h
#ifndef TREEMODEL_H
#define TREEMODEL_H
#include
#include
#include
class TreeItem;
//! [0]
class TreeModel : public QAbstractItemModel
{
Q_OBJECT
public:
explicit TreeModel(const QString &data, QObject *parent = 0);
~TreeModel();
QVariant data(const QModelIndex &index, int role) const override;
Qt::ItemFlags flags(const QModelIndex &index) const override;
QVariant headerData(int section, Qt::Orientation orientation,
int role = Qt::DisplayRole) const override;
QModelIndex index(int row, int column,
const QModelIndex &parent = QModelIndex()) const override;
QModelIndex parent(const QModelIndex &index) const override;
int rowCount(const QModelIndex &parent = QModelIndex()) const override;
int columnCount(const QModelIndex &parent = QModelIndex()) const override;
private:
void setupModelData(const QStringList &lines, TreeItem *parent);
TreeItem *rootItem;
};
//! [0]
#endif // TREEMODEL_H
treemodel.cpp
/*
treemodel.cpp
Provides a simple tree model to show how to create and use hierarchical
models.
*/
#include "treeitem.h"
#include "treemodel.h"
#include
//! [0]
TreeModel::TreeModel(const QString &data, QObject *parent)
: QAbstractItemModel(parent)
{
QList<QVariant> rootData;
rootData << "Title" << "Summary";
rootItem = new TreeItem(rootData);
setupModelData(data.split(QString("\n")), rootItem);
}
//! [0]
//! [1]
TreeModel::~TreeModel()
{
delete rootItem;
}
//! [1]
//! [2]
int TreeModel::columnCount(const QModelIndex &parent) const
{
if (parent.isValid())
return static_cast<TreeItem*>(parent.internalPointer())->columnCount();
else
return rootItem->columnCount();
}
//! [2]
//! [3]
QVariant TreeModel::data(const QModelIndex &index, int role) const
{
if (!index.isValid())
return QVariant();
if (role != Qt::DisplayRole)
return QVariant();
TreeItem *item = static_cast<TreeItem*>(index.internalPointer());
return item->data(index.column());
}
//! [3]
//! [4]
Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
{
if (!index.isValid())
return 0;
return QAbstractItemModel::flags(index);
}
//! [4]
//! [5]
QVariant TreeModel::headerData(int section, Qt::Orientation orientation,
int role) const
{
if (orientation == Qt::Horizontal && role == Qt::DisplayRole)
return rootItem->data(section);
return QVariant();
}
//! [5]
//! [6]
QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent)
const
{
if (!hasIndex(row, column, parent))
return QModelIndex();
TreeItem *parentItem;
if (!parent.isValid())
parentItem = rootItem;
else
parentItem = static_cast<TreeItem*>(parent.internalPointer());
TreeItem *childItem = parentItem->child(row);
if (childItem)
return createIndex(row, column, childItem);
else
return QModelIndex();
}
//! [6]
//! [7]
QModelIndex TreeModel::parent(const QModelIndex &index) const
{
if (!index.isValid())
return QModelIndex();
TreeItem *childItem = static_cast<TreeItem*>(index.internalPointer());
TreeItem *parentItem = childItem->parentItem();
if (parentItem == rootItem)
return QModelIndex();
return createIndex(parentItem->row(), 0, parentItem);
}
//! [7]
//! [8]
int TreeModel::rowCount(const QModelIndex &parent) const
{
TreeItem *parentItem;
if (parent.column() > 0)
return 0;
if (!parent.isValid())
parentItem = rootItem;
else
parentItem = static_cast<TreeItem*>(parent.internalPointer());
return parentItem->childCount();
}
//! [8]
void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
{
QList<TreeItem*> parents;//父项
QList<int> indentations;//代表行缩进索引位置
parents << parent;
indentations << 0;//默认缩进0位置
int number = 0;//当前行号
while (number < lines.count()) {
int position = 0;//当前行的列索引
while (position < lines[number].length()) {
if (lines[number].at(position) != ' ')
break;
position++;
}
QString lineData = lines[number].mid(position).trimmed();
if (!lineData.isEmpty()) {
// Read the column data from the rest of the line.
QStringList columnStrings = lineData.split("\t", QString::SkipEmptyParts);
QList<QVariant> columnData;
for (int column = 0; column < columnStrings.count(); ++column)
columnData << columnStrings[column];
if (position > indentations.last()) {//表示遇到缩进,即是新的子项
// The last child of the current parent is now the new parent
// unless the current parent has no children.
if (parents.last()->childCount() > 0) {//当前父项最后一个子项添加为父项
parents << parents.last()->child(parents.last()->childCount()-1);
indentations << position;//更新行索引位置
}
} else {
while (position < indentations.last() && parents.count() > 0) {//返回上一级
parents.pop_back();
indentations.pop_back();
}
}
// Append a new item to the current parent's list of children.
parents.last()->appendChild(new TreeItem(columnData, parents.last()));
}
++number;//更新行号
}
}