[Interest] Replacing QIcon with QImage in a existing model, how can i do that?

Mark markg85 at gmail.com
Mon Nov 26 22:02:09 CET 2012

On Mon, Nov 26, 2012 at 5:10 PM, Jan Kundrát <jkt at flaska.net> wrote:
> On Saturday, 24 November 2012 22:43:54 CEST, Mark wrote:
>> Now i was expecting this to work:
>> setData(modelIndex, _my_qimage_thumbnail_, Thumbnail);
>> Sadly that doesn't work. setData will just return false. So what am i
>> doing wrong here? Is the index build up wrongly? Or do i need to do
>> some different role stuff?
> It is important to know what model implementation you're using. I'll assume you're subclassing a QAbstractItemModel. If you're using QStandardItemModel, you should call setItem() instead of setData(), according to the docs (because QSIM doesn't override setData() and QAIM's setData() doesn't do anything but return false).
> Your model's data() function typically checks the role and returns appropriate data for the index the caller is requesting. In this case, all you have to do is to update the data structure which your data() reimplementation references, which will make sure that on a subsequent call, your data() will return the QImage you just computed instead of the default icon.
> But that's not enough, because the views have no way to know that they should request the data once again, you shall have your model emit dataChanged() for the appropriate index at the time your process is finished with computing the thumbnail image.
> With kind regards,
> Jan
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Hi Jan,

Thank you for your reply! I was using KDirModel [1] and that should
just work with setData since it has an implementation for that. It's
the Qt::DecorationRole. The thing i missed is some odd if statement
for the column "Name" requirement [2 line 797]. After i set my column
to that one it worked :)

I don't really get why it has that odd requirement..

[1] http://api.kde.org/4.9-api/kdelibs-apidocs/kio/html/classKDirModel.html
[2] http://api.kde.org/4.9-api/kdelibs-apidocs/kio/html/kdirmodel_8cpp_source.html

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