CC++ Qt TreeWidget 嵌套节点操作技巧

在上一篇博文《C/C++ Qt TreeWidget 单层树形组件应用》中给大家演示了如何使用TreeWidget组件创建单层树形结构，并给这个树形组件增加了右键菜单功能，接下来将继续延申树形组件的使用，并实现对树形框多节点的各种操作，如下笔记是本人在开发中经常用到的一些基本操作技巧。
常用树形框节点间的操作方法如下:

TreeView 节点遍历
TreeWidget 初始化节点
TreeWidget 单击双击节点
TreeWidget 添加根节点
TreeWidget 添加子节点
TreeWidget 修改选中节点
TreeWidget 删除选中节点
TreeWidget 枚举全部节点
TreeWidget 枚举选中节点
TreeWidget 获取节点子节点

简单的节点遍历: 首先我们还是使用TreeView组件实现一个简单的多层嵌套树结构，代码运行后，首先循环设置3个外层节点，接着循环内层节点，并将内层中的QStandardItem追加到外层上面。

#include "mainwindow.h"#include "ui_mainwindow.h"#include <QTreeView>#include <QStandardItemModel>// By: LyShark// https://www.cnblogs.com/lysharkMainWindow::MainWindow(QWidget *parent) :QMainWindow(parent),ui(new Ui::MainWindow){ui->setupUi(this);QStandardItemModel *tree = new QStandardItemModel(0,3,this);ui->treeView->setColumnWidth(0,50);// 设置第1列长度ui->treeView->setColumnWidth(1,200);// 设置第2列长度ui->treeView->setColumnWidth(2,200);// 设置第3列长度tree->setHeaderData(0, Qt::Horizontal, tr("序号"));tree->setHeaderData(1, Qt::Horizontal, tr("姓名"));tree->setHeaderData(2, Qt::Horizontal, tr("年龄"));ui->treeView->setModel(tree);for (int i = 0; i < 4; ++i){// 设置3个外层节点QList<QStandardItem *> items;for (int i = 0; i < 3; ++i){QStandardItem *item = new QStandardItem(QString("%0").arg(i));if (0 == i)item->setCheckable(true);items.push_back(item);}tree->appendRow(items);// 设置内层for (int i = 0; i < 2; ++i){QList<QStandardItem *> childItems;for (int i = 0; i < 3; ++i){QStandardItem *item = new QStandardItem(QString("lyshark"));if (0 == i)item->setCheckable(true);childItems.push_back(item);}items.at(0)->appendRow(childItems);}}}MainWindow::~MainWindow(){delete ui;}

代码运行效果如下:

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初始化树形节点: 首先在开始操作元素之前,我们可以在MainWindow::MainWindow中对树形节点进行简单的初始化,插入几个测试节点.

#include "mainwindow.h"#include "ui_mainwindow.h"#include <iostream>#include <QTreeWidgetItem>#include <QString>// By: LyShark// https://www.cnblogs.com/lysharkMainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow){ui->setupUi(this);ui->treeWidget->clear();// 设置QTreeWidget的列数ui->treeWidget->setColumnCount(1);// 设置QTreeWidget标题隐藏ui->treeWidget->setHeaderHidden(true);// 创建QTreeWidget的朋友节点,父节点是treeQTreeWidgetItem *Friend = new QTreeWidgetItem(ui->treeWidget,QStringList(QString("朋友")));Friend->setIcon(0,QIcon(":/image/4.ico"));// 添加一个图标Friend->setFlags(Qt::ItemIsSelectable | Qt::ItemIsUserCheckable| Qt::ItemIsEnabled | Qt::ItemIsAutoTristate);Friend->setCheckState(0,Qt::Checked);// 给Friend添加一个子节点frdQTreeWidgetItem *frd = new QTreeWidgetItem(Friend);frd->setText(0,"www.lyshark.com");frd->setIcon(0,QIcon(tr(":/image/1.ico")));frd->setCheckState(0,Qt::Checked);// 默认选中状态QTreeWidgetItem *frs = new QTreeWidgetItem(Friend);frs->setText(0,"cdn.lyshark.com");frs->setIcon(0,QIcon(tr(":/image/1.ico")));frs->setCheckState(0,Qt::Unchecked);// 默认未选中// ----------------------------------------------------------// 创建名叫同学节点,父节点同样是treeQTreeWidgetItem * ClassMate = new QTreeWidgetItem(ui->treeWidget,QStringList(QString("同学")));ClassMate->setIcon(0,QIcon(":/image/5.ico"));// 添加一个图标ClassMate->setCheckState(0,Qt::Checked);// 默认选中//Fly是ClassMate的子节点QTreeWidgetItem *Fly = new QTreeWidgetItem(QStringList(QString("nas.lyshark.com")));Fly->setIcon(0,QIcon(tr(":/image/2.ico")));//创建子节点的另一种方法ClassMate->addChild(Fly);Fly->setCheckState(0,Qt::Checked);// 设置为选中QTreeWidgetItem *Fls = new QTreeWidgetItem(QStringList(QString("lyshark.cnblogs.com")));Fls->setIcon(0,QIcon(tr(":/image/2.ico")));ClassMate->addChild(Fls);Fls->setCheckState(0,Qt::Checked);// 设置为选中// ----------------------------------------------------------// 陌生人单独一栏QTreeWidgetItem*Strange = new QTreeWidgetItem(true);Strange->setText(0,"陌生人");Strange->setIcon(0,QIcon(":/image/6.ico"));// 添加一个图标ui->treeWidget->addTopLevelItem(ClassMate);ui->treeWidget->addTopLevelItem(Strange);// 增加文本到编辑框ui->plainTextEdit->appendPlainText("hello lyshark");//展开QTreeWidget的所有节点//ui->treeWidget->expandAll();//ui->treeWidget->resize(271,401);}MainWindow::~MainWindow(){delete ui;}

代码运行效果如下:

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单击双击节点反馈: 当我们将鼠标停靠在指定节点内并点击时,我们需要触发treeWidget_itemDoubleClicked属性让其反馈该行标题等基本属性.

// 当我们双击指定的成员时获取到该成员的名字void MainWindow::on_treeWidget_itemDoubleClicked(QTreeWidgetItem *item, int column){QString str = item->text(column);std::cout << str.toStdString().data() << std::endl;ui->plainTextEdit->appendPlainText(str.toStdString().data());}// 当我们单击指定成员时获取数据void MainWindow::on_treeWidget_itemClicked(QTreeWidgetItem *item, int column){QString str = item->text(column);std::cout << str.toStdString().data() << std::endl;ui->plainTextEdit->appendPlainText(str.toStdString().data());}

代码运行效果如下:

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【CC++ Qt TreeWidget 嵌套节点操作技巧】添加父节点/子节点: 通过代码的方式当点击on_pushButton_clicked时分别实现增加一个父节点和一个子节点的功能。

// 单击按钮添加新的父节点void MainWindow::on_pushButton_clicked(){QString NodeText = "新的父节点";QTreeWidgetItem*item = new QTreeWidgetItem(true);item->setText(0,NodeText);item->setIcon(0,QIcon(":/image/7.ico"));ui->treeWidget->addTopLevelItem(item);}// 单击按钮添加子节点void MainWindow::on_pushButton_4_clicked(){QTreeWidgetItem * item= ui->treeWidget->currentItem();if(item!=NULL)AddTreeNode(item,"新子节点","新子节点");elseAddTreeRoot("新子节点","新子节点");}

代码运行效果如下:

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删除选中节点: 首先选中要删除的指定节点，然后可以对该节点进行删除操作，删除子节点直接移除即可，删除父节点需要连同内部子节点一并删掉。

// 删除选中的节点void MainWindow::on_pushButton_3_clicked(){QTreeWidgetItem *currentItem = ui->treeWidget->currentItem();if(currentItem == NULL)return;// 如果没有父节点则直接删除if(currentItem->parent() == NULL){delete ui->treeWidget->takeTopLevelItem(ui->treeWidget->currentIndex().row());std::cout << ui->treeWidget->currentIndex().row() << std::endl;}else{// 如果有父节点就要用父节点的takeChild删除节点delete currentItem->parent()->takeChild(ui->treeWidget->currentIndex().row());}}

代码运行效果如下:

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修改指定节点名称: 单击后将指定节点修改为Modify并将图标设置为新的

// 修改节点// By: LyShark// https://www.cnblogs.com/lysharkvoid MainWindow::on_pushButton_2_clicked(){// 得到当前节点QTreeWidgetItem *currentItem = ui->treeWidget->currentItem();if(currentItem == NULL)return;// 修改选中项for(int x=0;x<currentItem->columnCount();x++){currentItem->setText(x,tr("Modify") + QString::number(x));currentItem->setIcon(x,QIcon(":/image/1.ico"));}}

代码运行效果如下:

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枚举所有节点元素: 枚举当前Tree中的所有节点元素，并将结果输出到右侧编辑框内。

// 枚举所有节点// By: LyShark// https://www.cnblogs.com/lyshark// 枚举所有节点void MainWindow::on_pushButton_5_clicked(){// 获取到全部的根节点数量int size = ui->treeWidget->topLevelItemCount();QTreeWidgetItem *child;for(int x=0;x<size;x++){// 输出所有父节点child = ui->treeWidget->topLevelItem(x);std::cout << "all root = "<< child->text(0).toStdString().data() << std::endl;ui->plainTextEdit->appendPlainText(child->text(0).toStdString().data());// 得到所有子节点计数int childCount = child->childCount();// std::cout << "all child count = " << childCount << std::endl;// 输出根节点下面的子节点for(int y=0;y<childCount;++y){QTreeWidgetItem *grandson = child->child(y);std::cout << "--> sub child = "<< grandson->text(0).toStdString().data() << std::endl;ui->plainTextEdit->appendPlainText(grandson->text(0).toStdString().data());}}}

代码运行效果如下:

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枚举选中节点元素: 枚举当前Tree中选中节点的元素，并将结果输出到右侧编辑框内。

// 枚举所有的 【选中】节点// https://www.cnblogs.com/lysharkvoid MainWindow::on_pushButton_7_clicked(){// 获取到全部的根节点数量int size = ui->treeWidget->topLevelItemCount();QTreeWidgetItem *child;for(int x=0;x<size;x++){// 输出所有父节点child = ui->treeWidget->topLevelItem(x);// 得到所有子节点计数int childCount = child->childCount();// 输出根节点下面的子节点for(int y=0;y<childCount;++y){QTreeWidgetItem *grandson = child->child(y);// 判断是否选中,如果选中输出父节点与子节点if(Qt::Checked == grandson->checkState(0)){std::cout << "root -> " << child->text(0).toStdString().data()<< "--> sub child = "<< grandson->text(0).toStdString().data() << std::endl;ui->plainTextEdit->appendPlainText(grandson->text(0).toStdString().data());}}}}

代码运行效果如下:

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获取选中子节点的父节点: 获取子节点的父节点ID,然后根据ID得到子节点名字。

void MainWindow::on_pushButton_6_clicked(){// 取所有的父节点QTreeWidgetItem *currentItem = ui->treeWidget->currentItem()->parent();int root_count = ui->treeWidget->indexOfTopLevelItem(currentItem);std::cout << "root Count = " <<root_count << std::endl;if(root_count != -1){// 指定序号对应的父节点名字QTreeWidgetItem *child;child = ui->treeWidget->topLevelItem(root_count);std::cout << "root name= "<< child->text(0).toStdString().data() << std::endl;ui->plainTextEdit->appendPlainText(child->text(0).toStdString().data());}}

代码运行效果如下:

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补充一下节点插入函数的定义,AddTreeRoot/AddTreeNode两个函数定义如下所示.

// mainwindow.h 中增加头部声明QTreeWidgetItem * AddTreeRoot(QString name,QString desc);QTreeWidgetItem * AddTreeNode(QTreeWidgetItem *parent,QString name,QString desc);// mainwindow.cpp 中增加实现部分QTreeWidgetItem * MainWindow::AddTreeRoot(QString name,QString desc){QTreeWidgetItem * item=new QTreeWidgetItem(QStringList()<<name<<desc);ui->treeWidget->addTopLevelItem(item);return item;}QTreeWidgetItem * MainWindow::AddTreeNode(QTreeWidgetItem *parent,QString name,QString desc){QTreeWidgetItem * item=new QTreeWidgetItem(QStringList()<<name<<desc);parent->addChild(item);return item;}

文章出处：https://www.cnblogs.com/LyShark/p/15611884.html
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