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Develop Android apps with Qt

This document is an old archive here just as reference.

The Qt Framework supports multi-platform software development in C++. The Qt SDK contains a development environment as well as a runtime libraries for many operating systems.

Unfortunately, the C++ compiler of the Android NDK became broken some releases ago and Google refused to fix the problem. More than that, Google announced to remove required parts from the NDK permanently. This is very annoing, it happened at a time when Qt was just fully adopted to Android. Therefore, I cannot recommend the use of Qt for Android anymore.

Bluetooth

I use personal computers and Android tablets to control home-made electronic devices. For this purpose, my devices are sometimes equipped with a Bluetooth interface of type BTM-222, HC-05 or HC-06. They support the RFCOMM protocol, also known as SPP profile.

Bluetooth Module HC-06

Download AndroidBluetooth.zip.

Qt introduced Bluetooth support for Android in release 5.3. I developed the class AndroidRfComm as an alternative, which works already with release 5.2. It can list already known devices quickly without having to run the lengthly device discovery process. AndroidRfComm is designed for the pattern "send a command and wait for the response". It provides a simple and useful timeout mechanism.

Programming example:

AndroidRfComm rfcomm;
if (rfcomm.isEnabled()) {
    rfcomm.connect("HC-06");
    if (rfcomm.isConnected()) {
        // Send a line of text
        rfcomm.sendLine("Hello");
        // Wait for the answer, max.200 milliseconds
        QString received=rfcomm.receiveLine(200);  
        rfcomm.disconnect();
    }
}
AndroidRfComm uses Googles Java API over JNI, because the Native Development Kit does not contain Bluetooth features.