QTreeWidget設置勾選按鈕

//test.h
//在頭文件裏添加兩個公用函數還有一個槽函數的聲明

#include <QTreeWidgetItem>
public:
 void initTreeWidget();
 void updateParentItem(QTreeWidgetItem *item);
public:
 void treeItemChanged(QTreeWidgetItem *item,int column);

//test.cpp
//在構造函數裏添加 connect()

 initTreeWidget();

 connect(ui->treeWidget,SIGNAL(itemChanged(QTreeWidgetItem *,int)),this,SLOT(treeItemChanged(QTreeWidgetItem*,int)));

//initTreeWidget() 的實現

void test::initTreeWidget()
{
    ui->treeWidget->clear();
    //第一組
    QTreeWidgetItem *group1=new QTreeWidgetItem(ui->treeWidget);
    group1->setText(0,"group1");
    group1->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    group1->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item11=new QTreeWidgetItem(group1);
    item11->setText(0,"item11");
    item11->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item11->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item12=new QTreeWidgetItem(group1);
    item12->setText(0,"item12");
    item12->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item12->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item13=new QTreeWidgetItem(group1);
    item13->setText(0,"item13");
    item13->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item13->setCheckState(0,Qt::Unchecked);

    //第二組
    QTreeWidgetItem *group2=new QTreeWidgetItem(ui->treeWidget);
    group2->setText(0,"group2");
    group2->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    group2->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item21=new QTreeWidgetItem(group2);
    item21->setText(0,"item21");
    item21->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item21->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item22=new QTreeWidgetItem(group2);
    item22->setText(0,"item22");
    item22->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item22->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item23=new QTreeWidgetItem(group2);
    item23->setText(0,"item23");
    item23->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item23->setCheckState(0,Qt::Unchecked);
}

//treeItemChanged(QTreeWidgetItem *item, int column)的實現
void test::treeItemChanged(QTreeWidgetItem *item, int column)
{
    QString itemText=item->text(0);
    //選中時
    if(Qt::Checked==item->checkState(0))
    {
        QTreeWidgetItem* parent=item->parent();
        int count=item->childCount();
        if(count>0)
        {
            for(int i=0;i<count;i++)
            {
                //子節點也被選中
                item->child(i)->setCheckState(0,Qt::Checked);
            }
        }
        else
        {
            //是子節點
            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::Unchecked);
            }
        }
        else
        {
            //是子節點
            updateParentItem(item);
        }
    }
}
//updateParentItem(QTreeWidgetItem *item) 的實現
void test::updateParentItem(QTreeWidgetItem *item)
{
    QTreeWidgetItem* parent=item->parent();
    if(parent==NULL)
    {
        return;
    }
    //選中的子節點個數
    int selectCount=0;
    int childCount=parent->childCount();
    for(int i=0;i<childCount;i++)
    {
        QTreeWidgetItem *childItem=parent->child(i);
        if(childItem->checkState(0)==Qt::Checked)
        {
            selectCount++;
        }
    }
    if(selectCount<=0)
    {
        //選中狀態
        parent->setCheckState(0,Qt::Unchecked);
    }
    else if(selectCount>0 && selectCount<childCount)
    {
        //部分選中狀態
        parent->setCheckState(0,Qt::PartiallyChecked);
    }
    else if(selectCount==childCount)
    {
        //未選中狀態
        parent->setCheckState(0,Qt::Checked);
    }
}