Qt中怎么实现Qtreewidget节点的撤销重做

Qt中怎么实现Qtreewidget节点的撤销重做,第1张

增与删

下面是添加的功能:

//这是添加根节点的功能实现this->connect(ui->Root_btn, SIGNAL(clicked(bool)), this, SLOT(addRoot()))void Widget::addRoot()

{

QString one = ui->first->text()

QString two = ui->second->text()

QString three = ui->third->text()

QTreeWidgetItem* item = new QTreeWidgetItem()

item->setText(0, one)

item->setText(1, two)

item->setText(2, three)

ui->Tree->addTopLevelItem(item)

}//这是添加叶子节点的实现this->connect(ui->Child_btn, SIGNAL(clicked(bool)), this, SLOT(addChild()))void Widget::addChild()

{

QString one = ui->first->text()

QString two = ui->second->text()

QString three = ui->third->text()

QTreeWidgetItem* parent = ui->Tree->currentItem()

QTreeWidgetItem* item = new QTreeWidgetItem()

item->setText(0, one)

item->setText(1, two)

item->setText(2, three) parent->addChild(item)

}

添加叶子节点字需要注意父节点的获取就可以了。

下面是删除节点的功能:

this->connect(ui->DEL_btn, SIGNAL(clicked(bool)), this, SLOT(deleteNode()))

void del(QTreeWidgetItem* node){if(node->childCount() >0)

{for(int i = 0i <node->childCount()i ++)

{del(node->child(i))

}

}

else

{

delete node

}

}

void Widget::deleteNode()

{

QTreeWidgetItem* item = ui->Tree->currentItem()

if(item->childCount() >0)

{for(int i = 0i <item->childCount()i ++)

{del(item->child(i))

}

}

delete item

}

删除节点时记得循环删除这个节点下面的所有的子节点。

1. 首先,需要设置自己的控件是支持拖放 *** 作的,按照如下设置即可:

setDragEnabled(true) //允许拖拽

setAcceptDrops(true) //允许放置

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2. 其次,我这个拖放 *** 作是基于QTreeView来完成的,因此继承这个QTeeView之后还需要实现startDrag()这个函数。它可以被理解成是拖放 *** 作的入口函数。

//开始拖拽事件

virtual void stratDrag(Qt::DropActions supportedAxtions)

//这个函数可以理解为拖放 *** 作的入口函数。当拖放开始进行时,就会发现断点会进到这里。

void CMyTree::stratDrag(Qt::DropActions supportedAxtions)

{

QDrag* pDrag = new QDrag(this)

QMimeData* pMimeData = new QMimeData

QModelIndex index = currentIndex()

if (pDrag &&pMimeData)

{

pDrag->setMimeData(pMimeData)

pDrag->exec(Qt::MoveAction)

}

}

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3. 接下来,拖放 *** 作肯定是离不开鼠标的按压与移动的。因此还需要实现以下几个虚函数。

//鼠标点击事件

virtual void mousePressEvent(QMouseEvent *event)

//拖拽进入事件

virtual void dragEnterEvent(QDragEnterEvent* event)

//拖拽移动事件

virtual void dragMoveEvent(QDragMoveEvent* event)

//拖放事件

virtual void dropEvent(QDropEvent *event)

//鼠标松开事件

virtual void mouseReleaseEvent(QMouseEvent *event)

//鼠标移动事件

virtual void mouseMoveEvent(QMouseEvent *event)

//鼠标悬停事件

virtual bool viewportEvent(QEvent *event)

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当一切准备工作完成后,再通过QTreeView与QStandardItemModel相结合,完成一些列的拖放 *** 作。本例大致需求是:将叶子节点拖放到不同组织下。整个源码如下:

//CMyTree.h

#pragma once

#include <QTreeView>

#include <QStandardItem>

class CMyTree :

public QTreeView

{

public:

CMyTree(QWidget* parent = nullptr)

protected:

//开始拖拽事件

virtual void stratDrag(Qt::DropActions supportedAxtions)

//鼠标点击事件

virtual void mousePressEvent(QMouseEvent *event)

//拖拽进入事件

virtual void dragEnterEvent(QDragEnterEvent* event)

//拖拽移动事件

virtual void dragMoveEvent(QDragMoveEvent* event)

//拖放事件

virtual void dropEvent(QDropEvent *event)

//鼠标松开事件

virtual void mouseReleaseEvent(QMouseEvent *event)

//鼠标移动事件

virtual void mouseMoveEvent(QMouseEvent *event)

//鼠标悬停事件

virtual bool viewportEvent(QEvent *event)

private:

QStandardItem* m_pDragItem

QStandardItem* m_pDropItem

}

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//CMyTree.cpp

#include "CMyTree.h"

#include <QDrag>

#include <QMimeData>

#include <QStandardItemModel>

#include <QMouseEvent>

CMyTree::CMyTree(QWidget* parent /* = nullptr */)

: QTreeView(parent)

, m_pDragItem(nullptr)

, m_pDropItem(nullptr)

{

setDropIndicatorShown(true)

setHeaderHidden(true) //隐藏表头

setDragEnabled(true) //允许拖拽

setAcceptDrops(true) //允许放置

}

void CMyTree::stratDrag(Qt::DropActions supportedAxtions)

{

QDrag* pDrag = new QDrag(this)

QMimeData* pMimeData = new QMimeData

QModelIndex index = currentIndex()

if (pDrag &&pMimeData)

{

pDrag->setMimeData(pMimeData)

pDrag->exec(Qt::MoveAction)

}

}

void CMyTree::mousePressEvent(QMouseEvent *event)

{

if (Qt::RightButton == event->button())

{

setDragEnabled(false)

}

else if (Qt::LeftButton == event->button())

{

setDragEnabled(true)

}

QTreeView::mousePressEvent(event)

}

void CMyTree::dragEnterEvent(QDragEnterEvent* event)

{

if (event->mimeData())

{

QStandardItemModel* pModel = (QStandardItemModel*)(this->model())

QPoint mousePos = event->pos()

QModelIndex localIndex = indexAt(mousePos)

m_pDragItem = pModel->itemFromIndex(localIndex)

QString strData = localIndex.data(Qt::DisplayRole).toString()

QRect rect = visualRect(localIndex)

event->accept()

}

}

void CMyTree::dragMoveEvent(QDragMoveEvent* event)

{

if (event->mimeData())

{

update()

event->accept()

}

}

void CMyTree::dropEvent(QDropEvent *event)

{

QStandardItemModel* pModel = (QStandardItemModel*)(this->model())

QPoint mousePos = event->pos()

QModelIndex localIndex = indexAt(mousePos)

m_pDropItem = pModel->itemFromIndex(localIndex)

QString strData = localIndex.data(Qt::DisplayRole).toString()

QRect rect = visualRect(localIndex)

//同组织下释放没效果

QStandardItem* pDragItemParent = m_pDragItem->parent()

QStandardItem* pDropItemParent = m_pDropItem->parent()

if (pDragItemParent == pDropItemParent)

{

return

}

else if (pDragItemParent &&pDropItemParent)

{

QStandardItem* pItem = new QStandardItem(m_pDragItem->data(Qt::DisplayRole).toString())

pDropItemParent->appendRow(pItem)

}

update()

}

void CMyTree::mouseReleaseEvent(QMouseEvent *event)

{

QTreeView::mouseReleaseEvent(event)

}

void CMyTree::mouseMoveEvent(QMouseEvent *event)

{

QTreeView::mouseMoveEvent(event)

}

bool CMyTree::viewportEvent(QEvent *event)

{

return QTreeView::viewportEvent(event)

}

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//CMyApp.h

#pragma once

#include <QtWidgets/QWidget>

#include <QStandardItemModel>

#include "ui_CMyApp.h"

class CMyApp : public QWidget

{

Q_OBJECT

public:

CMyApp(QWidget *parent = Q_NULLPTR)

void InitUI()

private:

Ui::CMyAppClass ui

QStandardItemModel* m_pModel

}

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//CMyApp.cpp

#include "CMyApp.h"

#include <QStandardItem>

CMyApp::CMyApp(QWidget *parent)

: QWidget(parent)

{

ui.setupUi(this)

m_pModel = new QStandardItemModel(ui.treeView)

InitUI()

}

void CMyApp::InitUI()

{

QStandardItem* pItem1 = new QStandardItem(QStringLiteral("法师"))

m_pModel->appendRow(pItem1)

QStandardItem* pItem1_1 = new QStandardItem(QStringLiteral("妲己"))

QStandardItem* pItem1_2 = new QStandardItem(QStringLiteral("小乔"))

QStandardItem* pItem1_3 = new QStandardItem(QStringLiteral("西施"))

pItem1->appendRow(pItem1_1)

pItem1->appendRow(pItem1_2)

pItem1->appendRow(pItem1_3)

QStandardItem* pItem2 = new QStandardItem(QStringLiteral("法刺"))

m_pModel->appendRow(pItem2)

QStandardItem* pItem2_1 = new QStandardItem(QStringLiteral("不知火舞"))

QStandardItem* pItem2_2 = new QStandardItem(QStringLiteral("貂蝉"))

QStandardItem* pItem2_3 = new QStandardItem(QStringLiteral("上官婉儿"))

pItem2->appendRow(pItem2_1)

pItem2->appendRow(pItem2_2)

pItem2->appendRow(pItem2_3)

ui.treeView->setModel(m_pModel)

}

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//main.cpp

#include "CMyApp.h"

#include <QtWidgets/QApplication>

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

{

QApplication a(argc, argv)

CMyApp w

w.show()

return a.exec()

}


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原文地址: http://outofmemory.cn/bake/11458559.html

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