Custom QDirModel

[dude]

I think that there's maybe a misunderstanding. Maybe I explained the problem not too clear.

I'll try to describe it better.
So I need to insert a custom filesystem folder above the logical disks in a QTreeView using the QDirModel. That can be any user folder. For now it's a My Documents folder. I need that item to behave just like other filesystem items in the tree - expanding/collapsing, showing its contents, etc.

But you can convince your customer. Often people think and say they want something even if they don't need it.

I agree. But unfortunately, I'm not responsible for agreeing on project requirements, and they are already approved. I have to implement the task.

If it's a single item then when it is not expanded the view is useless and can be disabled or left empty

Yes, but to leave the item empty, I need to insert it in the tree in some way at first.

You are looking for QAbstractProxyModel. You need to subclass it and implement mapToSource(), mapFromSource() and reimplement QAbstractItemModel::data().

Can you please give me a hint on implementing these methods? As I understood, the main function of interest is mapToSource (). So if QDirModel stores indexes for the system logic drives as [0,1,2,...], I will need to shift them by value of 1, and when the model index equals 0, I'll need to perform some custom actions. But I can't understand how to do this

[wysota]

I'll try to describe it better.
So I need to insert a custom filesystem folder above the logical disks in a QTreeView using the QDirModel. That can be any user folder. For now it's a My Documents folder. I need that item to behave just like other filesystem items in the tree - expanding/collapsing, showing its contents, etc.

Believe me, I understand.

I agree. But unfortunately, I'm not responsible for agreeing on project requirements, and they are already approved. I have to implement the task.

Then use a proxy as advised.

Yes, but to leave the item empty, I need to insert it in the tree in some way at first.

Not the item - the view. It's like having a combobox with one item...

Can you please give me a hint on implementing these methods? As I understood, the main function of interest is mapToSource (). So if QDirModel stores indexes for the system logic drives as [0,1,2,...], I will need to shift them by value of 1, and when the model index equals 0, I'll need to perform some custom actions. But I can't understand how to do this

Hmm... I guess we might have misunderstood each other. I thought you meant:

My Documents
+--Drive 1
+--Drive 2
...

but it seems you want:
+My Documents
+Drive 1
+Drive 2
...

So My Documents is not "above" Drive 1 and Drive 2 but "before" them... right?

In that case I suggest you subclass QDirModel as you'll want to provide some data that doesn't exist in the model. Or do you just want to show the contents of some subfolder on one of the disks as children of the added item? If the latter, then you can go with a proxy. You just need to return one more row for an invalid parent, shift row numbers by 1 in mapToSource and mapFromSource for invalid parent and return the model index of the "linked" folder instead of the (0,0, invalid) index. You might have a problem the other way round as a source index of the target folder can be mapped into two indexes of the proxy and you'll have to decide which one to choose.

[dude]

but it seems you want:
+My Documents
+Drive 1
+Drive 2

Yes, that's what I need

So My Documents is not "above" Drive 1 and Drive 2 but "before" them... right?

Yes

In that case I suggest you subclass QDirModel as you'll want to provide some data that doesn't exist in the model.

I think that what I really need. I thought about it earlier but couldn't find any example of subclassing QDirModel neither at Trolltech, nor anywhere else

Or do you just want to show the contents of some subfolder on one of the disks as children of the added item? If the latter, then you can go with a proxy.

I didn't quite catch that

[wysota]

I think that what I really need. I thought about it earlier but couldn't find any example of subclassing QDirModel neither at Trolltech, nor anywhere else

That's because it's not meant to be subclassed.

I didn't quite catch that

"My Documents" is usually a link to some other real folder on the disk. I mean exactly such situation. Otherwise you'll have to craft the contents of the folder yourself.

[dude]

I really appreciate you're still trying to help me, but unfortunately I still don't see if QDirModel really fits my needs. I spend two days already just trying to find a way to implement my needs, but it seems to me that I'd better stay with good old QTreeWidget
The Interview framework takes too much much effort to make use of, unfortunately

[wysota]

Maybe if you try to explain your exact goal (not an intermediate goal but the ultimate one), we'll be able to help you better.