Postings tagged with Qt
The infrastructure of the Maliit project
It took us a while to transform the Maliit project into a real opensource project. At first there was only public code, later some wiki pages @ meego.com together with constantly changing components in the official MeeGo bugtracker, then a public mailing list.
After that we tried to become independent of MeeGo ...
How we enable others to write 3rd party plugins with Maliit
We finally published a video about Maliit - an input method framework including a virtual keyboard - and 3rd party plugins. Kudos goes to Jon for making time for that.
This video highlights one of Maliit's key features: pluggable input methods which come with their very own user interfaces. The Chinese input methods show how Maliit offers support for composed characters. The video is proof that 3rd party development for Maliit (open-source and proprietary) is ...
Qt Quick best practices: Using Components
The next article in the series about Qt Quick best practices has been published (but don't miss out the other one about property bindings). This time, I talked about Components, and how they can help to keep your QML code clean and maintainable. The team behind the N9 Developer blog has been a great help to me, especially Ville Lavonious ...
Miniature 0.5 'London 1851' released
From the release notes: "Miniature now supports different languages thanks to a determined community of translators. Thank you for your effort! This is why we are dedicating this release to the first international chess tournament, celebrated in London on 1851.
Miniature 0.5 is being released for MeeGo Harmattan (Nokia N9 & N950) and Maemo (Nokia N900). Thanks to everybody involved in the initial Maemo attempts and the experimental version that was made ...
Using MeeGo Keyboard from git on your Nokia N9
Usually AEGIS, the N9's security framework, protects system packages from being replaced. As such, files belonging to a system package can't be overwritten. And that's definitely a good thing, because otherwise each download from OVI store would put the user at a considerable risk.
Maliit is such a system package, but its flexible architecture allows for a creative way to replace the MeeGo Keyboard with a more recent version. This can be
useful if you want to testdrive new features and to … nah whom am ...
Best practices in using Qt Quick
I am writing a series about best practices in using Qt Quick. It will be published on the official N9 Developer blog. The introduction and first article have already appeared. Your feedback on that series is very much welcomed.
Better GTK+ support in Maliit
So far, using Maliit's virtual keyboard in GTK+ applications required fetching and compiling a GTK+ input method brigde yourself. Not any more. With the latest release, GTK+ applications should just work out of the box, thanks to Jon's integration efforts. Right at the same time, Łukasz was looking into using Maliit together with GTK+ applications on his Ubuntu desktop. He ...
Devhelp books in QtCreator
Had a few problems focusing on my work today, so I came up with this little hack: A script converting devhelp books into Qt help collections.
Together with QtCreator's autotools plugin it should help turning QtCreator into a proper GNOME IDE.
Next steps: Let QtCreator index devhelp books automatically. Also on my wishlish: A code ...
Real users, real feedback
We released Maliit 0.80.7 on Friday. Over these last days, I am doubly proud about our project. Not only did the N9's virtual keyboard get astonishing reviews across the board, but what's even better: We managed to keep this software open-source. In our communities, there will always be those who focus too ...
They call us crazy, but we store Contacts in Tracker
Visa authorities playing bad games with Chandni gave me the chance to talk about the QtContacts tracker plugin, which I and others where working on for that past few months. In case you've missed that early talk, here are the slides.
Interesting to just watch George from KDE to talk about similar things.
Using C++ enums in QML
When mapping Qt/C++ API's to QML, or, to put it more precisely, making a Qt/C++ API available to QML, road bumps are to be expected. One such bump is the mapping of C++ enums.
If you happen to create enums inside a QObject, then it will be exported to QML via the Q_ENUMS helper:
SomeEnumsWrapper
: public QObject
{
Q_OBJECT
Q_ENUMS(SomeState)
public:
...
Qt Contributors Summit is over
Really enjoyed the Qt Contributors Summit. Nice, open minded people. Café Moskau turned out as awesome location for technical orientated meetings.
Even held my own little session about my griefs with QObject life-cycle. We found some few chances for improvement, but we also sadly had to conclude that proper two-phase construction and destruction isn't possible in C++, unless you forbid stack allocation and ...
Input methods and Wayland in Qt5
I was attending the Qt Contributors' Summit 2011. During the key note, it was promised that everything is up for discussion so I took my chance to discuss about improving input methods support for Qt5.
After some initial discussions with Kristian Høgsberg (Wayland, of course) and Jørgen Lind (who works on Qt Lighhouse), ...
Qt Contributors' Summit
.
A bit odd for something with my background? Does that mean I am leaving the GNOME universe?
No. It just happens in Berlin, and I've just spent lots of time on letting QtContacts use some awesome GNOME technology (tracker). On the summit I'll try to convince some Qt core guys, that maybe UTF-8 ...
QGraphicsItem: When you're doing it wrong
When you read through the Qt GraphicsView documentation, you might miss the detail that QGraphicsItem::pos() refers to the center of an item: "Their coordinates are usually centered around its center point (0, 0), [...] At item's position is the coordinate of the item's center point in its parent's coordinate system;".
Oh great, so the word "usually" indicates it is not enforced, and everyone can choose his own semantics when implementing QGraphicsItems ...
Operator Overloading
Just wondered right now why Qt doesn't provide a greater-than operator for QSize.
Well, indeed: How would you define this operator? Maybe like this?
inline bool
operator >(const QSize &a, const QSize &b)
{
return a.width() * a.height() > b.width() * b.height();
}
Or is this the proper definition?
...
Using DBus as lock-daemon
Recently I found this comment in the source code I am working with:
// what if both processes read in the same time and write at the same time, no increment
Please! Don't do such things! Don't just leave such comments in hope someone else will come around and will fix later. Please take the time to apply a locking mechanism.
Obvious choice when dealing with files would be to create a lock file. Unfortunately creating a ...
QML Hype
So yesterday I've skipped the chance to watch some "exciting" QML demos in Helsinki. This was quite surprising to some of my KDE rooted team mates. They didn't understand how I could not show the slightest sign of excitement.
Well, but actually I wonder for months: What's actually the fancy and awesome, the brilliant new, the exciting part of QML? It ...
Logging facility for Miniature
On Maemo 5, log output from your app isn't always accessible to the user. This has created problems for Miniature bug reports (see bug #8124). To solve this, I created a "Game Log" screen which allows to filter the messages (by a given log level, I might want to allow combinations, too). It ...
Testdriving the UI Extensions for Mobile on Maemo 5
Reading about Nokia's UI Extensions for Mobile (sources available) I wanted to quickly try it myself. So I looked at the provided examples, and this video is the result of what I came up with (well, of course it is FOSDEM-induced). The provided API allowed me to easily apply my previous ...
How to customize your view with delegates
The usual way in Qt, when an item view wants to render itself, is to ask the item model for everything, layout, style and the actual data. Storing view-specific layout information in the model itself means that views and models can always only exist in a 1:1 relationship. The logical conclusion: If you need to share a model between different views, you will probably have to add proxy models for each view. I wasn't satisfied with that idea, so I continued to research QStyledItemDelegates. They ...
Fragile API and invalid iterators
For the Miniature project I sometimes need to iterate over all graphics items in a QGraphicsScene, or more precisely, all items of a specific parent item, the chess board itself. For that, I use the QGraphicsItem::childItems() API. However, when used with STL-style iterators you have to be careful, since value types of that form can easily break the iterator idiom:
for (QList<QGraphicsItem *>::iterator iter = parent_item->childItems().begin();
iter != parent_item->childItems().end();
++iter)
{
...
About delegates and cell renderers - data formatting in Qt
Warning: the following blog post has a rant-to-usefulness ratio of 3:1.
Last week I needed to perform some data formatting on Qt list view. From reading the documentation alone I could not find a satisfying answer. When asking on IRC the answer was to use proxy models. This would have worked, but having two models for one view can create all kind of correspondence problems (think of sorting etc.). And there is [this ...
Qt 4.6 for Maemo: It works!
Today at work, David King kindly informed me that there was some new Qt package in extras-devel. This could only mean one thing - I immediately fired up my scratchbox environment and installed the packages, trying to confirm that this new version would run with Qlom. And in fact, it was surprisingly painless. Thanks to autotroll, a simple QT_PATH env variable did all the magic, hooray! ...
Miniature - it moves!
How it begun
When I read Quim's thread about the idea for a better Maemo chess app I knew I wanted to join the project. To me, it's all about the device and the sparkling Hildon UX. I really want a good chess app, for myself! I want to play chess online, everywhere! And I want to analyze ...
Wt - a Qt-ish web toolkit written in C++
First of all, C++ for web apps doesn't necessarily make it easier to write them. Compared to other solutions (let's say Django) you'll end up writing a lot more code. And you have to be very very careful with memory leaks.
But that isn't the point. The main advantage of this framework is how close it is to desktop applications. Porting your Qt desktop application to the web is certainly easier with Wt than with any other solution, as you keep most of the widget API and also the signal and slots paradigm (which should allow to port the ...
Who wants my feedback for the Maemo6-Qt tech preview?
During the Maemo Summit there were several talks about the upcoming Maemo 6 platform and also about the transition from GTK+/Hildon to Qt. One of them - the "(Introduction to the) Harmattan UI framework" also mentioned where to get the code for the Maemo 6 UI Framework from. So I went there and cloned the two available repos (tech preview of the framework ...
First steps with Qt
I started to look into Qt with the help of "Foundations of Qt Development" by Johan Thelin. As with its counter-part it shares the decent text and the sometimes not-so-convincing examples. Perhaps code examples from a book should generally be maintained like a real project (including bugtracker, mailing list/forum and public repository), since that allows the examples to improve over time.
...
