QT的Model-View实现大批量数据展示

一、完整源代码

1.项目结构

2.各文件代码展示

define.h

#pragma once
#include <QVector>//学生信息
typedef struct _STUDENT {QString name;   //姓名int score1;     //语文成绩int score2;     //数学成绩int score3;     //外语成绩_STUDENT(){name = "";score1 = score2 = score3 = 0;}
}STUDENT, *PSTUDENT;//班级信息
typedef struct _CLASS {QString name;   //班级QVector<STUDENT*> students;_CLASS(){name = "";}
}CLASS;

mainwindow.h

#pragma once#include <QtWidgets/QWidget>
#include "ui_mainwindow.h"
#include "define.h"class TreeModel;
class TreeItem;class MainWindow : public QWidget
{Q_OBJECTpublic:MainWindow(QWidget *parent = Q_NULLPTR);private slots:void on_btn1_clicked(); //QStandardItemModelvoid on_btn2_clicked(); //自定义modelvoid SlotItemSelect(const QModelIndex &modelIndex);void SlotAddItem();void SlotRightMenu(const QPoint &pos);void SlotTreeMenuDelete();private:Ui::MainWindowClass *ui;QVector<CLASS*> mClasses;   //模拟数据TreeModel *model;
};

mainwindow.cpp

#include "mainwindow.h"
#include "TreeItem.h"
#include "TreeModel.h"#include <QMenu>
#include <QTreeView>
#include <QStandardItemModel>
#include <QStandardItem>
#include <QItemSelectionModel>MainWindow::MainWindow(QWidget *parent): QWidget(parent), ui(new Ui::MainWindowClass())
{ui->setupUi(this);//初始化模拟数据：学生成绩//10个班级、每个班级10000个学生，共10W行记录int nClass = 10;int nStudent = 100000;for (int i = 0; i < nClass; i++){CLASS* c = new CLASS;c->name = QString("class%1").arg(i);for (int j = 0; j < nStudent; j++){STUDENT* s = new STUDENT;s->name = QString("name%1").arg(j);s->score1 = s->score2 = s->score3 = (j % 10) * 10;c->students.append(s);}mClasses.append(c);}connect(ui->btn1, &QPushButton::clicked, this, &MainWindow::on_btn1_clicked);connect(ui->btn2, &QPushButton::clicked, this, &MainWindow::on_btn2_clicked);connect(ui->treeView, &QTreeView::clicked, this, &MainWindow::SlotItemSelect);connect(ui->pushButton, &QPushButton::clicked, this, &MainWindow::SlotAddItem);connect(ui->treeView, &QTreeView::customContextMenuRequested, this, &MainWindow::SlotRightMenu);ui->treeView->setContextMenuPolicy(Qt::CustomContextMenu);
}void MainWindow::on_btn1_clicked()
{//1，QTreeView常用设置项QTreeView* t = ui->treeView;//    t->setEditTriggers(QTreeView::NoEditTriggers);			//单元格不能编辑t->setSelectionBehavior(QTreeView::SelectRows);			//一次选中整行t->setSelectionMode(QTreeView::SingleSelection);        //单选，配合上面的整行就是一次选单行
//    t->setAlternatingRowColors(true);                       //每间隔一行颜色不一样，当有qss时该属性无效t->setFocusPolicy(Qt::NoFocus);                         //去掉鼠标移到单元格上时的虚线框//2，列头相关设置t->header()->setHighlightSections(true);                //列头点击时字体变粗，去掉该效果t->header()->setDefaultAlignment(Qt::AlignCenter);      //列头文字默认居中对齐t->header()->setDefaultSectionSize(100);                //默认列宽100t->header()->setStretchLastSection(true);               //最后一列自适应宽度t->header()->setSortIndicator(0, Qt::AscendingOrder);    //按第1列升序排序//3，构造ModelQStringList headers;headers << QStringLiteral("班级/姓名")<< QStringLiteral("语文")<< QStringLiteral("数学")<< QStringLiteral("外语")<< QStringLiteral("总分")<< QStringLiteral("平均分")<< QStringLiteral("是否合格")<< QStringLiteral("是否评优");QStandardItemModel* model = new QStandardItemModel(ui->treeView);model->setHorizontalHeaderLabels(headers);foreach(CLASS* c, mClasses){QStandardItem *pItemClass = new QStandardItem(c->name);model->appendRow(pItemClass);foreach(STUDENT* s, c->students){//二级节点：学生信息int score1 = s->score1;int score2 = s->score2;int score3 = s->score3;int nTotal = score1 + score2 + score3;int nAverage = nTotal / 3;bool bPass = true;if (score1 < 60 || score2 < 60 || score3 < 60){//任意一门课不合格则不合格bPass = false;}bool bGood = false;if (score1 >= 90 && score2 >= 90 && score3 >= 90){//每门课都达到90分以上评优bGood = true;}QList<QStandardItem*> items;QStandardItem* item0 = new QStandardItem(s->name);QStandardItem* item1 = new QStandardItem(QString::number(score1));QStandardItem* item2 = new QStandardItem(QString::number(score2));QStandardItem* item3 = new QStandardItem(QString::number(score3));QStandardItem* item4 = new QStandardItem(QString::number(nTotal));QStandardItem* item5 = new QStandardItem(QString::number(nAverage));QStandardItem* item6 = new QStandardItem(bPass ? QStringLiteral("合格") : QStringLiteral("不合格"));QStandardItem* item7 = new QStandardItem(bGood ? QStringLiteral("优秀") : QStringLiteral("-"));items << item0 << item1 << item2 << item3 << item4 << item5 << item6 << item7;pItemClass->appendRow(items);}}t->setModel(model);
}void MainWindow::on_btn2_clicked()
{//1，QTreeView常用设置项QTreeView* t = ui->treeView;//    t->setEditTriggers(QTreeView::NoEditTriggers);			//单元格不能编辑t->setSelectionBehavior(QTreeView::SelectRows);			//一次选中整行t->setSelectionMode(QTreeView::SingleSelection);        //单选，配合上面的整行就是一次选单行
//    t->setAlternatingRowColors(true);                       //每间隔一行颜色不一样，当有qss时该属性无效t->setFocusPolicy(Qt::NoFocus);                         //去掉鼠标移到单元格上时的虚线框//2，列头相关设置t->header()->setHighlightSections(true);                //列头点击时字体变粗，去掉该效果t->header()->setDefaultAlignment(Qt::AlignCenter);      //列头文字默认居中对齐t->header()->setDefaultSectionSize(100);                //默认列宽100t->header()->setStretchLastSection(true);               //最后一列自适应宽度t->header()->setSortIndicator(0, Qt::AscendingOrder);    //按第1列升序排序//3，构造ModelQStringList headers;headers << QStringLiteral("班级/姓名")<< QStringLiteral("语文")<< QStringLiteral("数学")<< QStringLiteral("外语")<< QStringLiteral("总分")<< QStringLiteral("平均分")<< QStringLiteral("是否合格")<< QStringLiteral("是否评优");model = new TreeModel(headers, ui->treeView);TreeItem *pRootItem = model->root();foreach(CLASS* c, mClasses){TreeItem *pClass = new TreeItem(pRootItem);pClass->setLevel(1);pClass->setPtr(c);pRootItem->appendChild(pClass);foreach(STUDENT* s, c->students){TreeItem* itemStudent = new TreeItem(pClass);itemStudent->setLevel(2);   //设为一级节点，供显示时判断节点层级来转换数据指针类型itemStudent->setPtr(s);     //保存STUDENT* s为其数据指针，显示时从STUDENT*取内容显示pClass->appendChild(itemStudent);}}t->setModel(model);
}void MainWindow::SlotItemSelect(const QModelIndex &modelIndex)
{TreeItem *pItem = static_cast<TreeItem*>(modelIndex.internalPointer());QString strText = QString::number(pItem->level());strText += "\n" + QString::number(pItem->row());ui->plainTextEdit->setPlainText(strText);
}void MainWindow::SlotAddItem()
{QItemSelectionModel *pSelectionModel = ui->treeView->selectionModel();if (pSelectionModel->hasSelection()) {// 获取选中的索引列表QModelIndexList selectedIndexes = pSelectionModel->selectedIndexes();// 一般情况下，QTreeView 是单选，所以可以直接获取第一个选中的索引QModelIndex selectedIndex = selectedIndexes.first();// 如果需要处理特定列的数据，可以通过 QModelIndex 访问模型中的数据//QVariant data = selectedIndex.data(Qt::DisplayRole);TreeItem *pItem = static_cast<TreeItem*>(selectedIndex.internalPointer());TreeItem *pParentItem = pItem->parentItem();STUDENT* s = new STUDENT;s->name = QString("name10086");s->score1 = s->score2 = s->score3 = 10086;TreeItem *pAddItem = new TreeItem(pParentItem);pAddItem->setPtr(s);pAddItem->setLevel(2);pParentItem->appendChild(pAddItem);ui->treeView->setModel(model);// 方法1，递归方法//QModelIndex pParentIndex = model->indexOfItem(pParentItem);// 方法2，通过createIndexQModelIndex pParentIndex = model->indexFromItem(pParentItem);ui->treeView->collapse(pParentIndex);ui->treeView->expand(pParentIndex);}
}void MainWindow::SlotRightMenu(const QPoint &pos)
{//创建右键菜单QMenu menu;//添加actionQAction *actionDelete = new QAction(QStringLiteral("删除"));menu.addAction(actionDelete);connect(actionDelete, &QAction::triggered, this, &MainWindow::SlotTreeMenuDelete);menu.exec(ui->treeView->viewport()->mapToGlobal(pos));
}void MainWindow::SlotTreeMenuDelete()
{QItemSelectionModel *pSelectionModel = ui->treeView->selectionModel();if (pSelectionModel->hasSelection()){QModelIndexList selectedIndexes = pSelectionModel->selectedIndexes();QModelIndex selectedIndex = selectedIndexes.first();TreeItem *pItem = static_cast<TreeItem*>(selectedIndex.internalPointer());TreeItem *pParentItem = pItem->parentItem();pParentItem->removeChild(pItem->row());for (int i = 0; i < pParentItem->getChildList().size(); i++){TreeItem *pItemTemp = pParentItem->getChildList().at(i);pItemTemp->setRow(i);}QModelIndex pParentIndex = model->indexFromItem(pParentItem);ui->treeView->collapse(pParentIndex);ui->treeView->expand(pParentIndex);}
}

TreeItem.h

#pragma once
#include <QVariant>
#include <QList>
class TreeItem
{
public:explicit TreeItem(TreeItem *parentItem = nullptr);~TreeItem();int childCount() const;                 //子节点计数int row() const;                        //获取该节点是父节点的第几个子节点void appendChild(TreeItem *item);void removeChild(int index);QList<TreeItem*> getChildList();TreeItem *parentItem();                 //获取父节点指针TreeItem *child(int row);               //获取第row个子节点指针//核心函数：获取节点第column列的数据QVariant data(int column) const;//设置、获取节点是几级节点（就是树的层级）int level() { return m_nLevel; }void setLevel(int level) { m_nLevel = level; }//设置、获取节点存的数据指针void setPtr(void* p) { m_pPtr = p; }void* ptr() { return m_pPtr; }//保存该节点是其父节点的第几个子节点，查询优化所用void setRow(int row) {m_nRow = row;}private:TreeItem *m_pParentItem;QList<TreeItem*> m_listChildItems;int m_nLevel;void *m_pPtr;int m_nRow;};

TreeItem.cpp

#include "TreeItem.h"
#include "define.h"
TreeItem::TreeItem(TreeItem *parentItem /*= nullptr*/)
{m_pParentItem = parentItem;
}TreeItem::~TreeItem()
{}int TreeItem::childCount() const
{return m_listChildItems.count();
}int TreeItem::row() const
{return m_nRow;
}void TreeItem::appendChild(TreeItem *item)
{item->setRow(m_listChildItems.size());   //item存自己是第几个，可以优化效率m_listChildItems.append(item);
}void TreeItem::removeChild(int index)
{delete m_listChildItems.takeAt(index); // 删除并释放元素的内存
}QList<TreeItem*> TreeItem::getChildList()
{return m_listChildItems;
}TreeItem * TreeItem::parentItem()
{return m_pParentItem;
}TreeItem * TreeItem::child(int row)
{return m_listChildItems.value(row);
}QVariant TreeItem::data(int column) const
{if (m_nLevel == 1){//一级节点，班级if (column == 0){CLASS* c = (CLASS*)m_pPtr;return c->name;}}else if (m_nLevel == 2){//二级节点学生信息STUDENT* s = (STUDENT*)m_pPtr;switch (column){case 0: return s->name;case 1: return QString::number(s->score1);case 2: return QString::number(s->score2);case 3: return QString::number(s->score3);case 4: return QString::number(s->score1 + s->score2 + s->score3);case 5: return QString::number((s->score1 + s->score2 + s->score3) / 3);case 6:{if (s->score1 < 60 || s->score2 < 60 || s->score3 < 60){//任意一门课不合格则不合格return QStringLiteral("不合格");}else{return QStringLiteral("合格");}}case 7:{if (s->score1 >= 90 && s->score2 >= 90 && s->score3 >= 90){//每门课都达到90分以上评优return QStringLiteral("优秀");}else{return QStringLiteral("-");}}default:return QVariant();}}return QVariant();
}

TreeModel.h

#pragma once
#include "TreeItem.h"
#include <QAbstractItemModel>
class TreeModel : public QAbstractItemModel
{Q_OBJECT
public:explicit TreeModel(QStringList headers,QObject *parent = nullptr);~TreeModel();//以下为自定义model需要实现的一些虚函数，将会被Qt在查询model数据时调用//headerData: 获取表头第section列的数据//data: 核心函数，获取某个索引index的元素的各种数据//      role决定获取哪种数据，常用有下面几种：//      DisplayRole（默认）：就是界面显示的文本数据//      TextAlignmentRole：就是元素的文本对齐属性//      TextColorRole、BackgroundRole：分别指文本颜色、单元格背景色//flags: 获取index的一些标志，一般不怎么改//index: Qt向你的model请求一个索引为parent的节点下面的row行column列子节点的元素，在本函数里你需要返回该元素的正确索引//parent：获取指定元素的父元素//rowCount: 获取指定元素的子节点个数（下一级行数）//columnCount: 获取指定元素的列数Qt::ItemFlags flags(const QModelIndex &index) const override;QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const override;QModelIndex parent(const QModelIndex &child) const override;int rowCount(const QModelIndex &parent = QModelIndex()) const override;int columnCount(const QModelIndex &parent = QModelIndex()) const override;public:TreeItem *itemFromIndex(const QModelIndex &index) const;QModelIndex indexFromItem(const TreeItem *item) const;QModelIndex indexOfItem(TreeItem *item) const;QModelIndex recursiveIndexSearch(TreeItem *currentItem, TreeItem *targetItem) const;TreeItem *root();private:QStringList m_listHeaders;TreeItem *m_pRootItem;
};

TreeModel.cpp

#include "TreeModel.h"TreeModel::TreeModel(QStringList headers, QObject *parent /*= nullptr*/):QAbstractItemModel(parent)
{m_listHeaders = headers;m_pRootItem = new TreeItem;
}TreeModel::~TreeModel()
{}Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
{if (!index.isValid()){return 0;}return QAbstractItemModel::flags(index);
}// 返回表头第section列的数据
QVariant TreeModel::headerData(int section, Qt::Orientation orientation, int role /*= Qt::DisplayRole*/) const
{if (orientation == Qt::Horizontal){if (role == Qt::DisplayRole){return m_listHeaders.at(section);}}return QVariant();
}QVariant TreeModel::data(const QModelIndex &index, int role /*= Qt::DisplayRole*/) const
{if (!index.isValid()){return QVariant();}TreeItem *item = static_cast<TreeItem*>(index.internalPointer());if (role == Qt::DisplayRole){return item->data(index.column());}return QVariant();
}QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent /*= QModelIndex()*/) const
{if (!hasIndex(row, column, parent))return QModelIndex();TreeItem *parentItem;if (!parent.isValid()){parentItem = m_pRootItem;}else{parentItem = static_cast<TreeItem *>(parent.internalPointer());}TreeItem *pChildItem = parentItem->child(row);if (pChildItem){return createIndex(row,column,pChildItem);}else{return QModelIndex();}
}QModelIndex TreeModel::parent(const QModelIndex &child) const
{if (!child.isValid())return QModelIndex();TreeItem *childItem = static_cast<TreeItem*>(child.internalPointer());TreeItem *parentItem = childItem->parentItem();if (parentItem == m_pRootItem)return QModelIndex();return createIndex(parentItem->row(), 0, parentItem);
}int TreeModel::rowCount(const QModelIndex &parent /*= QModelIndex()*/) const
{TreeItem *parentItem;if (parent.column() > 0)return 0;if (!parent.isValid())parentItem = m_pRootItem;elseparentItem = static_cast<TreeItem*>(parent.internalPointer());return parentItem->childCount();
}int TreeModel::columnCount(const QModelIndex &parent /*= QModelIndex()*/) const
{return m_listHeaders.size();;
}TreeItem * TreeModel::itemFromIndex(const QModelIndex &index) const
{if (!index.isValid())return nullptr;TreeItem *item = static_cast<TreeItem *>(index.internalPointer());return item;
}QModelIndex TreeModel::indexFromItem(const TreeItem *item) const
{TreeItem *pItem = const_cast<TreeItem *>(item);if (pItem->parentItem() == m_pRootItem){return createIndex(pItem->row(), 0, pItem);}return QModelIndex();
}QModelIndex TreeModel::indexOfItem(TreeItem *item) const
{// 如果模型是树形结构，可以递归遍历查找return recursiveIndexSearch(m_pRootItem, item);
}QModelIndex TreeModel::recursiveIndexSearch(TreeItem *currentItem, TreeItem *targetItem) const
{if (currentItem == targetItem) {// 如果找到了目标项，返回其索引return createIndex(currentItem->row(), 0, currentItem);}// 递归搜索子项for (int i = 0; i < currentItem->childCount(); ++i) {QModelIndex idx = recursiveIndexSearch(currentItem->child(i), targetItem);if (idx.isValid()) {return idx;}}return QModelIndex();
}TreeItem * TreeModel::root()
{return m_pRootItem;
}

3.界面

二、重要部分代码解释

1.TreeModel.cpp

在TreeMode中，最重要的是data()函数，该函数决定数据是否能够直接在View层进行显示。该接口中的QModelIndex是树中哪个结点下哪一行哪一列的索引（Model-View主要依赖于QModelIndex来取数据显示）。QModelIndex详解看：QT模型视图MVC系列教程（2）-模型数据索引QModelIndex详解-CSDN博客

QVariant TreeModel::data(const QModelIndex &index, int role /*= Qt::DisplayRole*/) const
{if (!index.isValid()){return QVariant();}TreeItem *item = static_cast<TreeItem*>(index.internalPointer());if (role == Qt::DisplayRole){return item->data(index.column());}return QVariant();
}

2.TreeItem.cpp

TreeItem是自定义的一个item类，也就是树中显示的每一行数据在Model中的存储。View层会通过data函数来取要显示的数据。比如TreeModel::data中的return item->data(index.column());

QVariant TreeItem::data(int column) const
{if (m_nLevel == 1){//一级节点，班级if (column == 0){CLASS* c = (CLASS*)m_pPtr;return c->name;}}else if (m_nLevel == 2){//二级节点学生信息STUDENT* s = (STUDENT*)m_pPtr;switch (column){case 0: return s->name;case 1: return QString::number(s->score1);case 2: return QString::number(s->score2);case 3: return QString::number(s->score3);case 4: return QString::number(s->score1 + s->score2 + s->score3);case 5: return QString::number((s->score1 + s->score2 + s->score3) / 3);case 6:{if (s->score1 < 60 || s->score2 < 60 || s->score3 < 60){//任意一门课不合格则不合格return QStringLiteral("不合格");}else{return QStringLiteral("合格");}}case 7:{if (s->score1 >= 90 && s->score2 >= 90 && s->score3 >= 90){//每门课都达到90分以上评优return QStringLiteral("优秀");}else{return QStringLiteral("-");}}default:return QVariant();}}return QVariant();
}