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Thread: QT in Android -- Example for accessing the GPS Service

  1. #1
    Join Date
    Mar 2010
    Heredia, Costa Rica
    Thanked 16 Times in 13 Posts
    Qt products
    Qt4 Qt5
    Unix/X11 Windows

    Smile QT in Android -- Example for accessing the GPS Service


    Note: This application uses Necessitas that is a QT Lighthouse port to Android devices by BogDan Vatra. Please find all what you need to build the example here:


    After two weeks of intense headaches I finally got a QT application to use the Android GPS service and have location readings.

    You can access it from:

    PLEASE read the README_ME_FIRST_OR_IT_WILL_NOT_WORK file before you get too excited!

    For BogDan Vatra et al.:
    I had to make some slight changes to:
    1- qtmain_android.cpp

    And I sadly had to add a new java class called to eu/licentia/necessitas/industrius . Yo can read the readme file to find out why.

    I would love to include those changes in the android-lighthouse project if you can direct me how. I am not very versed with git stuff.

    I tested it on my Samsung Galaxy 5 (Android 2.1). I built the apk using the latest sdk and ndk. I downloaded android-lighthouse from git.

    The normal jni.h that its included in the original qtmain_android.cpp is not compatible with the jni.h from Oracle. Hence the inclusion of Oracle's jni.h in the .pro.

    With no further comments, enjoy the GPS from QT applications in Android!

    License information inside the readme
    18th May 2011 at 12:57 (GMT+3) - I just posted a new tar.gz. It corrects a bug in the qtmain_android.cpp with prevented other applications to run because they don't have
    Last edited by qlands; 18th May 2011 at 10:57.

  2. The following 3 users say thank you to qlands for this useful post:

    ceoccarter (27th June 2011), raja26 (16th November 2011), Xplat (27th November 2011)

  3. #2
    Join Date
    Oct 2010
    Thanked 1 Time in 1 Post
    Qt products
    Qt3 Qt4 Qt/Embedded
    Unix/X11 Windows Symbian S60

    Default Re: QT in Android -- Example for accessing the GPS Service

    Hello, thank for such a great & useful post. Please use this link to contrubute to necessitas. BogDan is a member of Qt website. Surely some one will notify him about your contributions.
    Thank you!

  4. #3
    Join Date
    Mar 2013

    Default Re: QT in Android -- Example for accessing the GPS Service

    thank you for the post

  5. #4
    Join Date
    Sep 2013
    Qt products
    Qt5 Qt/Embedded
    Unix/X11 Windows Android Maemo/MeeGo

    Question Re: QT in Android -- Example for accessing the GPS Service

    This thread is little bit old, but i am facing similar problem.

    I am trying to load jar library which is described here

    I am using Qt5.1.1

    This is sample of code and corresponding debug printout
    jclass Intent = environment->FindClass("android/content/Intent");
    qDebug() << "Intent" << Intent;
    jclass Activity = environment->FindClass("android/app/Activity");
    qDebug() << "Activity" << Activity;

    jclass D2xxManager = environment->FindClass("com/ftdi/j2xx/D2xxManager");
    qDebug() << "D2xxManager" << D2xxManager;
    jclass FtDeviceInfoListNode = environment->FindClass("com/ftdi/j2xx/D2xxManager$FtDeviceInfoListNode");
    qDebug() << "FtDeviceInfoListNode" << FtDeviceInfoListNode;
    e = virtualMachine->DetachCurrentThread();

    D/Qt (17677): ../androjqt/main.cpp:53 (int main(int, char**)): Intent 0x1d200011
    D/Qt (17677): ../androjqt/main.cpp:55 (int main(int, char**)): Activity 0x1d200015
    D/Qt (17677): ../androjqt/main.cpp:58 (int main(int, char**)): D2xxManager 0x0
    D/Qt (17677): ../androjqt/main.cpp:60 (int main(int, char**)): FtDeviceInfoListNode 0x0
    E/AndroidRuntime(17677): FATAL EXCEPTION: Thread-398
    E/AndroidRuntime(17677): java.lang.NoClassDefFoundError: com/ftdi/j2xx/D2xxManager$FtDeviceInfoListNode
    E/AndroidRuntime(17677): at Method)
    E/AndroidRuntime(17677): Caused by: java.lang.NoClassDefFoundError: com/ftdi/j2xx/D2xxManager
    E/AndroidRuntime(17677): ... 1 more
    E/AndroidRuntime(17677): Caused by: java.lang.ClassNotFoundException: com.ftdi.j2xx.D2xxManager
    E/AndroidRuntime(17677): at dalvik.system.BaseDexClassLoader.findClass(BaseDex

    Here i see that finding classes in general is working, but my important library can't be found.
    I have the two jar files in project/android/libs

    Is nowadays still necessary to patch the qtmain_android.cpp ?
    I haven't built qt from sources, it is from official binary distribution.

    Am i doing something wrong?
    Where is some documentation about loading third party jar libraries?

    Thank you for any help

  6. #5
    Join Date
    Oct 2013
    Qt products
    Qt Jambi

    Default Re: QT in Android -- Example for accessing the GPS Service

    I have bookmarked this and will return soon more about it thank you.
    [url]Dessert Recipes: The Ultimate Dessert Recipe Book, Easy and Delicious Homemade Desserts[/url]

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