QML signals on PySide

I studied QML with signal-slot communication across to Python a bit.
If you are looking for examples in source code, see

• gitorious.org/pyside-example-qml-signalslot/qml-signalslot
• gitorious.org/maximum-pvr/mxmanager

The latter one use PySide but not QML, and has a preview video elsewhere in this blog. Here are my earlier experiments.

This video shows a very small application, consisting of two files - webview.qml and webview-qml.py.
The first three signals originate from QML and Python opens up a QMessageBox to display them, along by printing to stdout. The third signal will emit a fourth signal from Python to QML, with an url as a parameter, and the url will open inside a WebView.

This app evolves the idea a bit further. The HTML5 canvas demos seen in the video are not by me, they are from the web. There is a state machine working behind the scenes.

Compiling PySide on OS X

Binary packages of PySide are available from developer.qt.nokia.com/wiki/PySideBinariesMacOSX. You only need to compile it yourself if you have explicit reason to.

However, if for any reason you would like to compile it yourself, read on. First of all, download Qt SDK. After it has been installed you can use this Makefile script to download, compile and package PySide from git master.

$ git clone git://gitorious.org/~lamikae/pyside/lamikae-pyside-packaging.git
$ cd lamikae-pyside-packaging/osx/
$ make package

Maybe after an hour or more you should have a .pkg file, which has PySide dynamically linked to Qt installed from official dmg.
Install it with the command:

$ sudo installer -pkg pyside-<version>.pkg -target "/"

See if it works (if there is no error, it does =) and try out some of the official PySide examples.

$ python -c "from PySide import QtCore"

You can inspect the package contents by

$ xar -xf pyside-<version>.pkg Bom && lsbom package.pkg/Bom