QTreeWidget 复选框checkbox使用

使用QTreewidget时，用到复选框。还有一个苛刻的要求，即在选中或取消选中时，还要做一些操作。刚开始参考了网上的一些方法，参考了https://www.cnblogs.com/doubleeleven/articles/3894250.html，使用itemChange(QTreeWidgetItem*,int)信号，可以实现，但是不满足我个人的需求：我在点选时，要在事件中做其他操作，而每个节点的checkbox状态改变时，itemChange都会被触发，如我的例子中，我选中目标1时，目标1的所有子节点会被选中，如果有3个子节点，一共会触发3+1次itemChange，这不是我想看到的。所以，我尝试使用另一种方法，期望满足条件。

本文只是在学习的层面讨论，不讨论方法优劣。时刻抱持实用主义的观点，不管白猫黑猫，只要捉住老鼠就是好猫。

 

头文件：

#ifndef MYDLG_H
#define MYDLG_H

#include <QDialog>
#include <QTreeWidget>
#include <map>
using namespace std;

namespace Ui {
class MyDlg;
}

class MyDlg : public QDialog
{
    Q_OBJECT

public:
    explicit MyDlg(QWidget *parent = 0);
    ~MyDlg();

private slots:
    void on_btnQuit_clicked();
    void TreeItemClicked(QTreeWidgetItem* item, int col);
private:
    Ui::MyDlg *ui;
    map<QTreeWidgetItem*, Qt::CheckState> m_mapItemState;
    
    
    void InitTree();//初始化
    //添加节点
    QTreeWidgetItem* AddTreeItem(QTreeWidget* pTree, QTreeWidgetItem* parentItem, QString itemTxt);
    //获取当前的所有checkbox状态，和选中的节点
    void GetCheckItem(QTreeWidget* pTree, QList<QString>& listTarget);
    void ChangeChildItemState(QTreeWidgetItem* thisItem);//根据点击的节点，来改变节点的子节点状态
    void ChangeParentItemState(QTreeWidgetItem* thisItem);//根据点击的节点，来改变节点的父节点状态
    //获取节点的上次状态
    Qt::CheckState GetItemState(QTreeWidgetItem* item, map<QTreeWidgetItem*, Qt::CheckState>& mapItemState);
    
};

#endif // MYDIALOG_H

 

 

源文件：

#include "MyDlg.h"
#include "ui_MyDlg.h"
#include <QDebug>

MyDlg::MyDlg(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::MyDlg)
{
    ui->setupUi(this);
    InitTree();

    //首次获得节点状态
    QList<QString> list;
    GetCheckItem(ui->treeWidget, list);
}

MyDlg::~MyDlg()
{
    delete ui;
}

void MyDlg::on_btnQuit_clicked()
{

}

void MyDlg::TreeItemClicked(QTreeWidgetItem *item, int col)
{
    if(item->checkState(0) == GetItemState(item, m_mapItemState))//item状态是否改变
        return;
    ChangeChildItemState(item);
    ChangeParentItemState(item);
    QList<QString> listTarget;
    GetCheckItem(ui->treeWidget, listTarget);
    qDebug() << listTarget;

}

void MyDlg::InitTree()
{
    connect(ui->treeWidget, SIGNAL(itemClicked(QTreeWidgetItem*,int)), this, SLOT(TreeItemClicked(QTreeWidgetItem*,int)));
    ui->treeWidget->header()->setHidden(1);
    QTreeWidgetItem* topItem = new QTreeWidgetItem;
    topItem->setCheckState(0, Qt::Unchecked);
    topItem->setText(0, "目标列表");
    ui->treeWidget->addTopLevelItem(topItem);
    QTreeWidgetItem* item1 = AddTreeItem(ui->treeWidget, topItem, "目标1");
    QList<QString> listTarget;
    listTarget << "目标11" << "目标12";
    for(int i = 0; i < listTarget.count(); i++){
        AddTreeItem(ui->treeWidget, item1, listTarget.at(i));
    }

    QTreeWidgetItem* item2 = AddTreeItem(ui->treeWidget, topItem, "目标2");
    listTarget.clear();
    listTarget << "目标21" << "目标22" << "目标23";
    for(int i = 0; i < listTarget.count(); i++){
        AddTreeItem(ui->treeWidget, item2, listTarget.at(i));
    }

    QTreeWidgetItem* item3 = AddTreeItem(ui->treeWidget, topItem, "目标3");
    listTarget.clear();
    listTarget << "目标31" << "目标32" << "目标33" << "目标34";
    for(int i = 0; i < listTarget.count(); i++){
        AddTreeItem(ui->treeWidget, item3, listTarget.at(i));
    }

    ui->treeWidget->expandAll();
}

QTreeWidgetItem *MyDlg::AddTreeItem(QTreeWidget *pTree, QTreeWidgetItem *parentItem, QString itemTxt)
{
    QTreeWidgetItem *item = new QTreeWidgetItem(parentItem);
    item->setFlags(item->flags() | Qt::ItemIsUserCheckable);
    item->setCheckState(0, Qt::Unchecked);
    item->setText(0, itemTxt);
    return item;
}

void MyDlg::GetCheckItem(QTreeWidget *pTree, QList<QString> &listTarget)
{//这个本来是为了获取选中的节点文本。后来增加了获取所有节点的状态，以备将来判断节点状态是否改变
    m_mapItemState.clear();

    QTreeWidgetItemIterator it(pTree);
    while (*it) {
        if((*it)->checkState(0) == Qt::Checked){
            QString itemTxt = (*it)->text(0);
            if(itemTxt.compare("") != 0){
                listTarget.push_back(itemTxt);
            }
        }
        m_mapItemState[(*it)] = (*it)->checkState(0);
        ++it;
    }
}
//遍历该节点下所有子节点
void MyDlg::ChangeChildItemState(QTreeWidgetItem *thisItem)
{
    int nChildCount = thisItem->childCount();
    if(nChildCount < 1) return;

    for(int i = 0; i < nChildCount; i++){
        thisItem->child(i)->setCheckState(0, thisItem->checkState(0));
        ChangeChildItemState(thisItem->child(i));
    }
}

void MyDlg::ChangeParentItemState(QTreeWidgetItem *thisItem)
{
    QTreeWidgetItem* parentItem = thisItem->parent();
    if(parentItem == NULL) return;

    int nChildCount = parentItem->childCount();
    int nSelected = 0;
    int nPartSelected = 0;
    for(int i = 0; i < nChildCount; i++){
        if(parentItem->child(i)->checkState(0) == Qt::Checked){
            nSelected++;
        }
        else if(parentItem->child(i)->checkState(0) == Qt::PartiallyChecked){
            nPartSelected++;
        }
    }
    //如果该节点有子节点被选中，但选中的节点个数小于子节点数，或者有子节点是半选中状态，则该节点为半选中
    if((nSelected > 0 && nSelected < nChildCount) || nPartSelected > 0){
        parentItem->setCheckState(0, Qt::PartiallyChecked);
    }
    else if(nSelected == nChildCount){
        parentItem->setCheckState(0, Qt::Checked);
    }
    else {
        parentItem->setCheckState(0, Qt::Unchecked);
    }
    ChangeParentItemState(parentItem);
}

Qt::CheckState MyDlg::GetItemState(QTreeWidgetItem *item, map<QTreeWidgetItem *, Qt::CheckState> &mapItemState)
{
    map<QTreeWidgetItem*, Qt::CheckState>::iterator iter = m_mapItemState.find(item);
    if(iter != m_mapItemState.end()){
        return iter->second;
    }
    return Qt::Unchecked;
} 

ui文件：

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MyDlg</class>
 <widget class="QDialog" name="MyDlg">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Dialog</string>
  </property>
  <layout class="QGridLayout" name="gridLayout">
   <item row="0" column="0" colspan="2">
    <widget class="QTreeWidget" name="treeWidget">
     <column>
      <property name="text">
       <string notr="true">1</string>
      </property>
     </column>
    </widget>
   </item>
   <item row="1" column="0">
    <spacer name="horizontalSpacer">
     <property name="orientation">
      <enum>Qt::Horizontal</enum>
     </property>
     <property name="sizeHint" stdset="0">
      <size>
       <width>298</width>
       <height>20</height>
      </size>
     </property>
    </spacer>
   </item>
   <item row="1" column="1">
    <widget class="QPushButton" name="btnQuit">
     <property name="text">
      <string>quit</string>
     </property>
    </widget>
   </item>
  </layout>
 </widget>
 <resources/>
 <connections/>
</ui>