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(→Install the new SDK) |
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== Install the new SDK == | == Install the new SDK == | ||
| - | The SDK can be downloaded from: | + | The SDK can be downloaded from: http://qt.nokia.com/downloads |
== Open and run the existing project with the new SDK == | == Open and run the existing project with the new SDK == | ||
The following is a rough overview of some steps the author found helpful on migrating an existing Fremantle Application to Harmattan. Feedback, comments, corrections etc. are highly appreciated!
Contents |
The SDK can be downloaded from: http://qt.nokia.com/downloads
First things first, if the application also runs natively on the OS you are developing, the first thing is to check whether it runs with the newly installed SDK as well.
The next step is to try if the application builds in the Harmattan ARMEL Scratchbox. Chances should be pretty good that it builds out of the box. If the application builds it can be tested on the Device (N950) or in the Emulator (QEMU). Note that at that point the application will look a lot like a common Desktop Qt application.
If necessary add new defines for Harmattan. Unfortunately it seems like there are no defines planned or intended to indicate Harmattan. The following hack by mzanetti helps to work around this issue. In the project file you can use the following to identify Harmattan:
# Thanks to mzanetti for this hack. exists($$QMAKE_INCDIR_QT"/../qmsystem2/qmkeys.h"): DEFINES += Q_WS_MAEMO_6
Then you can e.g. change your defines from:
#ifdef Q_WS_MAEMO_5
to something like:
#if defined(Q_WS_MAEMO_5) || defined(Q_WS_MAEMO_6)
If you could already run your application you will have noticed that it had a quite ugly "desktopish" look. To change this the user interface needs to be redone in QML (at least for the time being this seems the only option for now).
To get a first overview of QML etc. you can simply create a new example QML project using the SDK. In the SDK do
File -> New Project -> Qt Quick Project -> Harmattan Application
This should get you started with a first overview of what a QML project looks like and the parts of it. For more information about QML and the components that can be used see, e.g.:
As a very first step the author just copied the generated QML files, adapted the project file to include the new files and changed the main method of existing application to launch the demo QML application. Note: In the default Harmattan Application example the QML files will be embedded in the binary via resources. While this may be a good start and probably have other benefits (?). Placing these files at some place accessible via the file system will ease and speed up development.
Once QML is running in the application the files copied from the sample project can be changed to the desired look and feel of the application. The following links give some examples and overviews of the bits and pieces that can be used in QML UIs.
In case the application uses custom widgets, these can be adapted to work in QML as well. To get existing widgets working, using proxies as described in http://doc.qt.nokia.com/4.7-snapshot/declarative-cppextensions-qwidgets.html worked very well (to be honest the author did not try without proxies). The following code shows a quick and dirty declaration of such a proxy for a custom widget "AnalogMeterWidget":
class AnalogMeter : public VolumeMeter
{
Q_OBJECT
public:
AnalogMeter(QGraphicsItem* parent = 0)
: QGraphicsProxyWidget(parent)
{
widget = new AnalogMeterWidget(0);
setWidget(widget);
}
private:
AnalogMeterWidget *widget;
};
Also note that it seemed to be more practicable to register the proxies directly in the main method via something like
qmlRegisterType<AnalogMeter>("vumeter", 1, 0, "AnalogMeter");
instead of using a custom QML plugin as described in the link above. In the QML files you would then use
import vumeter 1.0
to import your stuff and something like
AnalogMeter {
id: vuMeter
}
to instantiate your class. Note: Using the approach as described here, the QML editor will complain about "unknown types" when you use your custom imports and widgets but this did not affect the functionality here. See also the next section for more information about connecting QML and C/C++ code.
Similarly as described above, using "qmlRegisterType" lets you use your own Qt classes in QML. This way it is easily possible to include many of the functionality of your "old" project in QML. Usefull links are:
Some of the existing parts of a Fremantle project are not needed for Harmattan (e.g. forms etc.). Those things do not need to be deleted but can be excluded for Harmattan build by changing the project file accordingly, e.g.:
exists($$QMAKE_INCDIR_QT"/../qmsystem2/qmkeys.h"){
DEFINES += Q_WS_MAEMO_6
QT+= declarative
FORMS = }
Defines Q_WS_MAEMO_6, adds the declarative parts needed for QML etc. and removes all forms for Harmattan builds. This is just an example. Similarly the install targets and files can be changed as well. This way it should still be possible to build the project for all targeted platforms such as Fremantle or Harmattan.
One nice feature of QML is that it it interpreted at runtime so changes in the QML part do not require a recompile. We can exploit this feature to speed up the development process by not embedding the QML files in the binary but store these files somewhere else where we can easily edit them. In the project file use, e.g.:
OTHER_FILES += qml/main.qml \ qml/MainPage.qml
INSTALLS += target ... qml
target.path = /usr/bin
...
qml.path = /usr/share/vumeter/qml
qml.files += qml/main.qml \
qml/MainPage.qml
In the main method you can then use
view.setSource(QUrl("/usr/share/vumeter/qml/main.qml"));
instead of
view.setSource(QUrl("qrc:/qml/main.qml"));
to load the QML files.
The desktop files for Harmattan are located in
desktop.path = /usr/share/applications/meegotouch
instead of
desktop.path = /usr/share/applications/hildon
TODO
TODO