Sunday, September 4, 2011

Porting Qt app to Harmattan

As I received Nokia N9 Dev kit from Qt Ambassador program, I started working on porting my existing Maemo 5 application to Maemo 6 (Harmattan/Meego) platform.

It seems from documentation that preferred way to create Meego application is by using QML and com.meego components. In order to make my Qt and QML application to work correctly on meego I needed to make quite a few changes.

First thing I noticed is that, Qt Widget are available on harmattan but that just for backword compatiblity and dose not provide native look and feel for Harmattan platform. That mean Qt Widget library are kind of useless on harmattan. We need to use meego touch library or meego QML component.

Some of my application were QWidget based or some were Graphics View based. I ported most of application to use QML and If i can not port to use QML then I  used QDeclarativeItem to load that component to QML.

For some of my application I was locking orientation, using "WA_Maemo5PortraitOrientation" flag in view.setAttribute(Qt::WA_Maemo5PortraitOrientation, true); API call, But on Harmattan I need to use following code in QML page.
        orientationLock: PageOrientation.LockPortrait
To make application full screen, I need to disable statusbar and toolbar from PageStackWindow. I used following code

PageStackWindow {
    showStatusBar: false
    showToolBar: false
In one of my application I was using GraphicsView framework, I loaded graphics view to QML using QDeclarativeItem and QGraphicsProxyWidget. Visit following link for more info. 

But after GraphicsView loaded to QML, view was displaying some white area that initially I was not able to remove. After a white I realized it was frame for graphics view. I removed it by using setFrameStyle API.
Desktop file also needs to be changed to locate icon correctly and to launch only single instance of application.
[Desktop Entry]
GenericName=app name
Comment=some comment
Exec=/usr/bin/single-instance /usr/bin/appname
Also in control file, to make your application user application and not system component, we need to add following flag.
Maemo-Flags: visible
I used following in my project file to transfer icon file to proper location.
unix  {
    isEmpty(PREFIX) {
        PREFIX = /usr
    BINDIR = $$PREFIX/bin
    DATADIR =$$PREFIX/share


    INSTALLS += target desktop icon64

    target.path =$$BINDIR

    desktop.path = $$DATADIR/applications
    desktop.files += ./image/$${TARGET}.desktop

    icon64.path = /usr/share/icons/hicolor/64x64/apps/
    icon64.files += ./image/$${TARGET}.png
I also faced segmentation fault while testing Webview with emulator, but on device it works fine.

That's all, most of my experience was smooth while porting and did not struggled much.


  1. Isnt the icon size for harmattan 80x80?

  2. Yes, icon size for harmattan is 80x80, but to avoid icon issue i placed, 80x80 icon to /usr/share/icons/hicolor/64x64/apps/

  3. Hi, when I use the "showStatusBar: false" property i always get a random peice of the status bar with the battery and wifi indicator still shown in the top left hadn corner of the screen, did this happen for you too??

  4. No, I did not face such problem when I use "showStatusBar: false", might be upgrading firmware solve the problem ?

  5. How did you upgrade the FW on the N950 :S I'm using the one the device came with v1.20011.22-6

  6. this link might help, though I have not tried flashing image my self.