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“Unboxing” the Android Things Developer Preview

Android Things is Google’s answer to creating an environment for IoT devices. Take a slimmed down Android build, add some sensor-specific APIs, and provide it on a number of powerful pre-integrated micro-boards and you have a ready-made platform for building a host of upcoming IoT devices. Android Things can take advantage of many existing Android libraries, toolkits, and APIs, making it easier and quicker for developers to turn ideas into product. What’s not to like?

We decided to test this …

Qt on Android: How to create an Android service using Qt

Starting with Qt 5.7, we added the ability to create Android services using Qt. In this article we’re going to see how to get started and also how to communicate between the two.

Before we get started I want to add a big bold WARNING about the performance! Because the services are run in the background for a very long time, make sure your service doesn’t drain the device battery!

Getting started

Step I: Extend QtService

Every single Qt Android …

Qt on Android: How to restart your application

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 my example I used it to restart Qt Quick Controls 2 gallery.

Sadly my fix was not accepted, because other platforms (iOS, IIRC) have this …

Qt on Android: How to use Android Toast

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 method. This method needs 3 params:

  • the context (we’ll use the activity)
  • the text to show
  • and the duration: one of LENGTH_SHORT (0) and

Qt on Android: How to convert Qt images to Android Images and vice-versa

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 going to use NDK’s support, so we need to make sure jnigraphics library is in libraries dependency in our .pro file:

LIBS += -ljnigraphics

Now …

Qt on Android: How to create a zero-copy Android SurfaceTexture QML item

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 our SurfaceTexture. As you can see it’s pretty useful.

In this tutorial we’re going to see how easy it is to create a media …

Qt on Android: How to run C++ code on Android UI thread

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 UI thread without writing any Java code. Qt 5.7 will bring will bring the same functionality.

Until Qt 5.7 is out, we need to …

Qt on Android Episode 7 - How to access and use Android Java API from your Qt on Android using JNI in a safe way.

Update: Here you have also the Chinese version, thanks goes to Foruok

In the last two Qt on Android episodes we learned how to use basic JNI on Android and how to use an external IDE to easily manage the Java part. In this episode, it is time to move forward and focus on extending our Qt on Android Java part and also how to interact with it using JNI in a “safe way”.

In this part we are …

Qt on Android Episode 6 - How to use Android Studio to extend and debug the Java part of your Qt application

Update: Here you have also the Chinese version, thanks goes to Foruok

In the last Qt on Android episode we learned the basics of JNI on Android in a Qt way. In this episode I’d like to focus on tools that will help us to be more productive when we extend our Qt on Android applications.

Using an external IDE to manage Java files.

Sadly, the Java support in Qt Creator is very limited, and in order to be productive …

Fun with Android

AKA: I know what you did last Christmas !

Hello folks,

I’d like to share with you a few things that I did during this Xmas.

Besides the fact I’ll never ever take a vacation before Xmas, because Brasov is a tourist attraction and it was FULL of tourists in that period. I could ski only once 🙁 , because it snowed just a few days before New Year and then the police closed the roads to the ski resort …

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