Some time ago, I wrote a code to restart the running application on Android. You might well ask why such a thing was needed. It was needed because there are cases where, whenever a user changes the theme, the application has to restart to apply the change (it can't be applied on the fly). In […]

From time to time I scroll through Qt-related forums and mailing lists, and whenever possible I try to help fellow developers out. The other day a StackOverflow thread caught my attention: a developer was asking "What is the purpose of operator RestrictedBool in QScopedPointer?" Indeed, looking at QScopedPointer's implementation, one notices the strange RestrictedBool usage. […]

To get you started on this, we'll be using KDAB's Android utils with the humble Toast. Toasts are small popups which are used to show the user some feedback. Check Google's API guide for more info about toasts. The easiest way to show a toast is to use Toast.makeText(Context context, CharSequence text, int duration) static […]

Sometimes we need to exchange images from Android world to Qt world and vice-versa, therefore in this article we're going to see how to convert a QImage to an Android Bitmap and how to convert an Android bitmap and an Android Drawable into a QImage. To get access to Android Bitmap data & info we're […]

Microsoft Windows has a long history of embedded operating systems going back to 1996, branded as Windows Embedded Compact, Windows Embedded CE, Windows CE, Windows Compact, Windows Phone, Windows Runtime, and an assortment of others. One of these fine platforms might even form the basis of your embedded product. Trouble is, with the shiny new […]

Motivation: Android SurfaceTexture is used by all Android classes that need to display (a lot of) frames, it can be used to display media player, camera, etc. You can also use it in combination with other players: OpenMAX, VLC, etc. (well, VLC and other C++ player are using MediaCodec) to decode the images directly to […]

Qt 5.6 has just been released! Packed with incredible new features, 5.6 is also the first long term support release of Qt: it will be supported for the next 3 years, giving developers a solid foundation for their current and upcoming projects. Once more, KDAB is confirmed to be the largest independent contributor to Qt, […]

KDSoap is a tool for creating client applications for web services without the need for any further component such as a dedicated web server. KDSoap lets you interact with applications which have APIs that can be exported as SOAP objects. The web service then provides a machine-accessible interface to its functionality via HTTP. You can […]

KD Chart 2.6.0 is a maintenance release with a limited number of new features. This release publishes feature additions and bugfixes since KD Chart 2.5.1. KDAB continues to offer a commercial license without flat fee support for KD Chart. Features: - Code updated to compile with Qt 5.6 - Optional line breaking for horizontal legends […]

I'd like to start a new series of Qt on Android articles, these will be small articles which will focus on useful features that you'll need on Android but which don't have any Qt API (yet). I'll start with two pretty useful functions. These functions will help us to run C++ code directly on Android […]

Back in November, Apple released the latest generation of it's Apple TV product. Besides the slightly improved hardware, the true new feature is the OS which is now officially based on iOS and comes with the dedicated SDK and App Store! So we started investigating what it would take to port Qt to tvOS and […]

In the last blog post we gave a very high level introduction to the Qt Quick 2 renderer. We also showed how various signals are emitted by the renderer during the synchronization and rendering steps. In this blog post we're going to discuss those signals and show how they can be used to implement overlays […]

What is GammaRay? For starters, it's a powerful electromagnetic wave, as well as a way to treat cancer. It’s also an under-appreciated German speed metal band. And it’s what gives Dr. Bruce Banner his big green alter ego. But Qt aficionados will know the GammaRay that we're talking about is an uber-powerful Qt debugger and […]

Holoplot UX - Example of modern user interface that could benefit from compressed textures. (KDAB designed UX, photo courtesy of Holoplot.) It’s every programmer’s worst nightmare. Your beautiful app is running at a snail’s pace, crippled by virtual memory swapping. Even worse, you’ve added one last bitmap resource, and suddenly unrelated chunks of the UX […]

If you’re already using QML in Qt, you know that it can help quickly create flexible user interfaces using little or no C++ programming. With a basic text file and some JavaScript logic, you can put together a pretty sophisticated interface like that shown in the Qt Quick Clock demo (below) with a minimum of […]

The Qt World Summit was a rocking blast! More than 800 delegates, two days packed with sessions (and an additional training day presented by KDAB). Many old faces, lots of new ones, and a packed programme of sessions with terrific technical content. Yours truly also happened to give a talk, "Integrating OpenGL with Qt Quick […]

The latest release of KD Reports further enhances your ability to get printable and exportable reports from code and XML descriptions. For those who like using CMake instead of qmake, you'll be glad to know KD Reports now comes with a fully functioning CMake buildsystem (see INSTALL-cmake.txt). In addition, we have added Frame element and […]

It's usually said "only improve performance where a profiler tells you to". I don't completely agree. Take a big C++ library like Qt: can you profile all classes and all code paths ? It would take a couple of years to accomplish and analyse the results. It's expensive: It usually only happens if the speed-up […]

In the last episode of this blog series we learned about the overall concepts of input methods in Qt, with a look behind the scenes to see how a key press event from the native windowing system travels through the Qt input stack until it appears on screen inside a QLineEdit. In that context, the […]

Good news, everyone! Qt 5.5 has just been released! The release process of Qt 5.5 has been focused on stabilizing and improving performances. Once more KDAB is proud to be a part of the release, with its engineers constantly providing contributions and patches, as demonstrated by the commit graph of the last 16 weeks: In […]