QT 中QtreeWidget使用

#include <widget.h>
#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QTreeWidgetItem>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
public:
    void init();
    void updateParentItem(QTreeWidgetItem* item);
private slots:
    void treeItemChanged(QTreeWidgetItem* item, int column);
private:
    Ui::Widget *ui;
};

#endif // WIDGET_H

#include <widget.cpp>
#include "widget.h"
#include "ui_widget.h"
#include <QString>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    init();
    connect(ui->treeWidget, SIGNAL(itemChanged(QTreeWidgetItem*,int)), this,
                                   SLOT(treeItemChanged(QTreeWidgetItem*,int)));
}
Widget::~Widget()
{
    delete ui;
}
void Widget::init()
{
    ui->treeWidget->clear();
    //第一个分组
    QTreeWidgetItem * group1 = new QTreeWidgetItem(ui->treeWidget);
    group1->setText(0, "group1");
    group1->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    group1->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem* subItem11 = new QTreeWidgetItem(group1);
    subItem11->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    subItem11->setText(0, "subItem11");
    subItem11->setCheckState(0, Qt::Unchecked);
    QTreeWidgetItem* subItem12 = new QTreeWidgetItem(group1);
    subItem12->setText(0, "subItem12");
    subItem12->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    subItem12->setCheckState(0, Qt::Unchecked);
    QTreeWidgetItem* subItem13 = new QTreeWidgetItem(group1);
    subItem13->setText(0, "subItem13");
    subItem13->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    subItem13->setCheckState(0, Qt::Unchecked);
    QTreeWidgetItem* subItem14 = new QTreeWidgetItem(group1);
    subItem14->setText(0, "subItem14");
    subItem14->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    subItem14->setCheckState(0, Qt::Unchecked);
    //第二个分组
    QTreeWidgetItem * group2 = new QTreeWidgetItem(ui->treeWidget);
    group2->setText(0, "group2");
    group2->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    group2->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem* subItem21 = new QTreeWidgetItem(group2);
    subItem21->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    subItem21->setText(0, "subItem21");
    subItem21->setCheckState(0, Qt::Unchecked);
    QTreeWidgetItem* subItem22 = new QTreeWidgetItem(group2);
    subItem22->setText(0, "subItem22");
    subItem22->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    subItem22->setCheckState(0, Qt::Unchecked);
    QTreeWidgetItem* subItem23 = new QTreeWidgetItem(group2);
    subItem23->setText(0, "subItem23");
    subItem23->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    subItem23->setCheckState(0, Qt::Unchecked);
    QTreeWidgetItem* subItem24 = new QTreeWidgetItem(group2);
    subItem24->setText(0, "subItem24");
    subItem24->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
    subItem24->setCheckState(0, Qt::Unchecked);
}
void Widget::treeItemChanged(QTreeWidgetItem *item, int column)
{
    QString itemText = item->text(0);
    //选中时
    if(Qt::Checked == item->checkState(0))
    {
        QTreeWidgetItem* parent = item->parent();
        int count = item->childCount();
        if(count > 0)
        {
            for(int i = 0; i < count; i++)
            {
                //子节点也被选中
                item->child(i)->setCheckState(0, Qt::Checked);
            }
        }
        else
        {
            //是子节点
            updateParentItem(item);
        }
    }
    else if(Qt::Unchecked == item->checkState(0))
    {
        int  count = item->childCount();
        if(count > 0)
        {
            for(int i = 0; i < count; i++)
            {
                item->child(i)->setCheckState(0, Qt::Checked);
            }
        }
        else
        {
            updateParentItem(item);
        }
    }
}
void Widget::updateParentItem(QTreeWidgetItem *item)
{
    QTreeWidgetItem* parent = item->parent();
    //如果是主节点
    if(parent == NULL) return;
    //选中子节点个数
    int selectedCount = 0;
    int childCount = parent->childCount();
    for(int i = 0 ; i < childCount; i++)
    {
        QTreeWidgetItem* chileItem = parent->child(i);
        if(chileItem->checkState(0) == Qt::Checked)
        {
            selectedCount++;
        }
    }
    if(selectedCount <= 0)
    {
        //选中状态
        parent->setCheckState(0, Qt::Unchecked);
    }
    else if(selectedCount > 0 && selectedCount < childCount)
    {
        //部分选中状态
        parent->setCheckState(0, Qt::PartiallyChecked);
    }
    else if(selectedCount == childCount)
    {
        //未选中状态
        parent->setCheckState(0, Qt::Checked);
    }
}