How to sort item names in treeview alphabetically ignorent of the case?

MNGL

Hi, Guys

Below is my treeview code, and I want sort to sort the directory keys alphabetically whatever whether they start with a capital letter or not, for example, the "auto-update" should be listed right after the "Audio", how to implement this? Thanks.

RegistryTreeView::RegistryTreeView(Registry &inRegistry, QWidget *inParent)
{
    mModel = new RegistryItemModel;
    mModel->setRegistry(&inRegistry);

    mTreeView = new QTreeView;
    mTreeView->setContextMenuPolicy(Qt::DefaultContextMenu);
    mTreeView->setModel(mModel);
    mTreeView->setItemDelegate(new RegistryItemDelegate(mModel));
    mTreeView->installEventFilter(new AutoSelectEventFilter(this));
    
    mainLayout->addWidget(mTreeView);
    
}

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JonB

@MNGL
You must either interpose a QSortFilterProxyModel between your model and the QTreeView so that you can use setSortCaseSensitivity(Qt::CaseInsensitive) (e.g. https://stackoverflow.com/questions/50693571/how-to-sort-qtableview-ignoring-case) or you could override the virtual QAbstractItemModel::sort() to implement your own case-insensitive sorting. If you do the latter be careful to maintain the correct tree structure, i.e. sorting only on siblings of each node separately.

MNGL

Thanks, @JonB

I tried the option 1, it worked, but it did not work with code in BOLD:
Is there any way to make the setItemDelegate to work with QSortFilterProxyModel object?

RegistryTreeView::RegistryTreeView(Registry &inRegistry, QWidget *inParent)
{
    mModel = new RegistryItemModel;
    mModel->setRegistry(&inRegistry);

    QSortFilterProxyModel *ProxyModel = new QSortFilterProxyModel(this);
    ProxyModel->setSourceModel(mModel);
    ProxyModel->setSortCaseSensitivity(Qt::CaseInsensitive);
    ProxyModel->sort(0, Qt::AscendingOrder);

    mTreeView = new QTreeView;
    mTreeView->setContextMenuPolicy(Qt::DefaultContextMenu);
    mTreeView->setModel(ProxyModel);
    **mTreeView->setItemDelegate(new RegistryItemDelegate(mModel));** //this line will cause abend.
    mTreeView->installEventFilter(new AutoSelectEventFilter(this));
    
    mainLayout->addWidget(mTreeView);
    
}

class RegistryItemDelegate : public QStyledItemDelegate
{
    Q_OBJECT;

public:

    RegistryItemDelegate(RegistryItemModel *inModel, QObject *inParent=NULL);
    //RegistryItemDelegate(QSortFilterProxyModel *inModel, QObject *inParent=NULL);
    virtual ~RegistryItemDelegate();

protected:
    virtual void initStyleOption(QStyleOptionViewItem *inOption, const QModelIndex &inIndex) const;


private:
    RegistryItemModel *mModel;
	
    QColor mModifiedColor;
    QIcon mFolderIcon;
};

Bonnie

@MNGL What's your RegistryItemModel's base class?
If it is subclassed from QStandardItemModel, I'd just add one custom role for sorting, something like

const int sort_role = Qt::UserRole + 1;

RegistryItemModel() {
    ...
    setSortRole(sort_role);
    ...
}

And save toLower() of the original text in every item's sort_role data

JonB

@MNGL said in How to sort item names in treeview alphabetically ignorent of the case?:

**mTreeView->setItemDelegate(new RegistryItemDelegate(mModel));** //this line will cause abend.

I don't know what abend means. Find out whether there is a problem with the new RegistryItemDelegate(mModel) or with the mTreeView->setItemDelegate().

MNGL

class RegistryItemModel : public QAbstractItemModel
{
Q_OBJECT;

public:
RegistryItemModel(QWidget *parent=NULL);
virtual ~RegistryItemModel();
......
}

if I don't comment out following line, the program will crash before the Main Window is launched.

mTreeView->setItemDelegate(new RegistryItemDelegate(mModel));

JonB

@MNGL
Yes, you said that earlier. Already suggested what you should do next. Also you can see the cause of "crashes" from the debugger.

MNGL

Thanks, @JonB JonB
QAbstractItemModel does not have a function called setSortRole.

Here is the crash screenshot:

MNGL

Does anyone have the code example on how to override the virtual QAbstractItemModel::sort() to implement case-insensitive sorting?

JonB

@MNGL said in How to sort item names in treeview alphabetically ignorent of the case?:

Thanks, @JonB JonB
QAbstractItemModel does not have a function called setSortRole.

It was @Bonnie who suggested that, if you had been using QStandardItemModel.

Here is the crash screenshot:

I'm not sure of the reason. It comes in your RegistryItemDelegate::initStyleOption() override, whose code so far you have steadfastly refused to show. When you create it you pass it mModel (I don't know why, I don't think you should be doing this), which is your source model. But the treeview is attached to the QSortFilterProxyModel model. At a guess, the QModelIndex &inIndex being passed is an index into the proxy model, but you are using it to index into the source model??

MNGL

@JonB

class RegistryItemDelegate : public QStyledItemDelegate
{
    Q_OBJECT;

public:

  //RegistryItemDelegate(RegistryItemModel *inModel, QObject *inParent=NULL);
    RegistryItemDelegate(QSortFilterProxyModel *mModel, QObject *inParent=NULL);
    virtual ~RegistryItemDelegate();

protected:
    virtual void initStyleOption(QStyleOptionViewItem *inOption, const QModelIndex &inIndex) const;


private:
  //RegistryItemModel *mModel;
    QSortFilterProxyModel *mModel;
    QColor mModifiedColor;
    QIcon mFolderIcon;
};

void RegistryItemDelegate::initStyleOption(QStyleOptionViewItem *inOption, const QModelIndex &inIndex) const
{
    QStyledItemDelegate::initStyleOption(inOption, inIndex);

    const Node *node = mModel->node(inIndex); //error C2039: 'node' : is not a member of 'QSortFilterProxyModel'
    if(node == NULL)
        return;

    if(!node->isDefault())
        inOption->palette.setColor(QPalette::Text, mModifiedColor);

    if(node->nodeType() == eRegDir && inOption->version == 4)
    { 
        ((QStyleOptionViewItemV4*)inOption)->features |= QStyleOptionViewItemV2::HasDecoration;
        ((QStyleOptionViewItemV4*)inOption)->icon = mFolderIcon;
    }
}

if I change the type of mModel from RegistryItemModel to QSortFilterProxyModel, I got following error:

error C2039: 'node' : is not a member of 'QSortFilterProxyModel'

JonB

@MNGL
OK. But I still don't know why you pass a mModel parameter to your delegate. I would be getting the model from the QModelIndex &inIndex() passed to initStyleOption().

If your screenshot shows it is crashing on the node->isDefault() line, what is a Node, how does mModel->node(inIndex) work, what is Node::isDefault()? Have you compiled for Debug with no code optimizations? Just in case the line is misleading, Q_ASSERT(mModel). Otherwise it looks like node is 0/nullptr for the exception at 0x00000000, though you test for that, so presumably it can't be....

BTW, you have not said, but are you still using Qt4 (it looks like you are), not Qt5/6??

MNGL

This post is deleted!

MNGL

@JonB ~~strikethrough text~~

it's obviously that object of QSortFilterProxyModel cannot replace the mModel of RegistryItemModel.
I'm using Qt 4.8.7, and what about override the QAbstractItemModel::sort() to implement your own case-insensitive sorting, where can find a code example?

MNGL

Here is the code change that fixed the crash:

void RegistryItemDelegate::initStyleOption(QStyleOptionViewItem *inOption, const QModelIndex &inIndex) const
{
    QStyledItemDelegate::initStyleOption(inOption, inIndex);

    //const Node *node = mModel->node(inIndex);
    const Node* node = nullptr;  //code change start

    QModelIndex sourceIndex = inIndex;
    auto proxyModel = dynamic_cast<const QAbstractProxyModel*>(sourceIndex.model());
    //We map the index back to its source as many times as needed.
    //We expect to do it once for now but that may change in the future.
    while (proxyModel) {
          sourceIndex = proxyModel->mapToSource(sourceIndex);
          proxyModel = dynamic_cast<const QAbstractProxyModel*>(sourceIndex.model());
    }
   
    auto regModel = dynamic_cast<const RegistryItemModel*>(sourceIndex.model()) ;
    if (regModel)
    node = regModel->node(sourceIndex);  //code change end
	
    if(node == NULL)
        return;

    if(!node->isDefault())
        inOption->palette.setColor(QPalette::Text, mModifiedColor);

    if(node->nodeType() == eRegDir && inOption->version == 4)
    { 
        ((QStyleOptionViewItemV4*)inOption)->features |= QStyleOptionViewItemV2::HasDecoration;
        ((QStyleOptionViewItemV4*)inOption)->icon = mFolderIcon;
    }
}