在QTreeView中维护checkstatus继承

我想做一些基本的:你有一个QTreeView。第一深度只包含文件夹，第二深度只包含文件。我想在每个项目旁边都有一个复选框，显示选中的状态。文件被选中或未选中，文件夹也可以被部分选中，这取决于它们的文件;我相信这一切都是很自然的。

我认为我应该去的方式是使用QStandardItemModel和QStandardItem的自定义子类填充它:DescriptionFileItem。也许这是个坏主意，如果有更简单的方法，请告诉我。

我尝试使用信号和插槽，以便文件上的信号CheckStateChanged连接到其包含文件夹上的插槽UpdateCheckedStateOnChildStateChanged。这要求我的DescriptionFileItem也继承QObject(顺便说一句，我很惊讶QStandardItem没有继承QObject)。我最初希望这将与提供的基类无缝地工作，但它没有:emitDataChanged()似乎没有触发我的模型的datachchanged()信号…

使用模型的dataChanged信号直接不起作用:它的调用是受保护的，所以你不能在没有子类化的情况下使用它(我认为这是我的下一步，除非有人能帮助我把它做好)。

此刻我有一个信号->插槽连接，不会工作，我不知道为什么;编译和链接工作正常。下面是代码;也许你能很容易地发现我的错误。我留下了一些注释行，这样你就可以看到我在之前的尝试中做错了什么。谢谢你的建议!

#ifndef DESCRIPTIONFILEITEM_H
#define DESCRIPTIONFILEITEM_H
#include <QStandardItem>
#include <Qt>
class DescriptionFileItem :  public QObject, public QStandardItem
{
    Q_OBJECT
public:
    explicit DescriptionFileItem(const QString & text, bool isFileName=false, QObject* parent = 0);
    void setData ( const QVariant & value, int role = Qt::UserRole + 1 );
    QVariant data( int role = Qt::UserRole + 1 ) const;
    QString text;
    Qt::CheckState checkedState;
    bool isFileName;
signals:
    void CheckStateChanged();
public slots:
    void UpdateCheckedStateOnChildStateChanged();
};
#endif // DESCRIPTIONFILEITEM_H   

对应的。cpp:

#include "DescriptionFileItem.h"
DescriptionFileItem::DescriptionFileItem(const QString & text, bool isFileName, QObject* parent):
    QObject(parent),QStandardItem(text)
{
    this->isFileName = isFileName;
    checkedState = Qt::Checked;
}
void DescriptionFileItem::setData ( const QVariant & value, int role){
    if(role == Qt::CheckStateRole){
        Qt::CheckState newCheckState = (Qt::CheckState)value.toInt();
        checkedState = newCheckState;
        if(isFileName){
            if(newCheckState == Qt::Unchecked || newCheckState == Qt::Checked){
                for(int i = 0; i<rowCount(); i++){
                    DescriptionFileItem* child = (DescriptionFileItem*)QStandardItem::child(i);
                    QModelIndex childIndex = child->index();
                    child->model()->setData(childIndex,newCheckState, Qt::CheckStateRole);
                    //child->setCheckState(newCheckState);
                    //child->setData(newCheckState,Qt::CheckStateRole);
                }
                /*if(rowCount()>1){
                    emit this->model()->dataChanged(this->child(0)->index(),this->child(rowCount()-1)->index());
                }else{
                    emit this->model()->dataChanged(this->child(0)->index(),this->child(0)->index());
                }*/
            }
        }else{
            emit CheckStateChanged();
        }
        //emit this->model()->dataChanged(this->index(),this->index());
    }else{
        QStandardItem::setData(value,role);
    }
}
QVariant DescriptionFileItem::data( int role ) const{
     if (role == Qt::CheckStateRole){
            return checkedState;
     }
     return QStandardItem::data(role);
}
void DescriptionFileItem::UpdateCheckedStateOnChildStateChanged()
{
    Qt::CheckState min = Qt::Checked;
    Qt::CheckState max = Qt::Unchecked;
    Qt::CheckState childState;
    for(int i = 0; i<rowCount(); i++){
        DescriptionFileItem* child = (DescriptionFileItem*)QStandardItem::child(i);
        childState = (Qt::CheckState) child->data(Qt::CheckStateRole).toInt();
        min = min>childState ? childState: min;
        max = max<childState ? childState: max;
    }
    if(min >= max)
        setData(min, Qt::CheckStateRole);
    else
        setData(Qt::PartiallyChecked, Qt::CheckStateRole);
}  

和连接/树的构造:

        DescriptionFileItem* descFileStdItem = new DescriptionFileItem(descriptionFileName, true);
        descFileStdItem->setFlags(Qt::ItemIsSelectable|Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsTristate);
        descriptionFileSIModel.appendRow(descFileStdItem);
        typedef pair<string,int> indexType;
        foreach(indexType index,dataFile->indexes){
            DescriptionFileItem* key_xItem = new DescriptionFileItem(index.first.c_str());
            descFileStdItem->appendRow(key_xItem);
            key_xItem->setFlags(Qt::ItemIsSelectable|Qt::ItemIsUserCheckable|Qt::ItemIsEnabled);
            QObject::connect(key_xItem,SIGNAL(CheckStateChanged()),descFileStdItem,SLOT(UpdateCheckedStateOnModelDataChanged()));
        }

编辑:最终答案，感谢stu(见下文)

void DataLoadWidget::ModelItemChanged(QStandardItem *item)
{
    QStandardItem* parent = item->parent();
    if(parent == 0){
        //folder state changed--> update children if not partially selected
        Qt::CheckState newState = item->checkState();
        if(newState != Qt::PartiallyChecked){
            for (int i = 0; i < item->rowCount(); i++)
            {
                item->child(i)->setCheckState(newState);
            }
        }
    }
    else{//child item changed--> count parent's children that are checked
        int checkCount = 0;
        for (int i = 0; i < parent->rowCount(); i++)
        {
            if (parent->child(i)->checkState() == Qt::Checked)
                checkCount++;
        }
        if(checkCount == 0)
            parent->setCheckState(Qt::Unchecked);
        else if (checkCount ==  parent->rowCount())
            parent->setCheckState(Qt::Checked);
        else
            parent->setCheckState(Qt::PartiallyChecked);
    }
}