Low-level Activity API
Most activities will use the Python API to implement activities. This page will document the underlying mechanism that non-Python activities need to conform to.
This documentation effort was started by Bert while implementing the Squeak-based Etoys activity. Please fill in missing pieces and correct mistakes!
Overview
An Activity Bundle can specify an executable in the activity.info's exec field. When installing the bundle, the path of this executable will be expanded and added to the list of DBus services in $HOME/.local/share/dbus-1/services/ using the DBus service name as specified in the service_name field. When launching an activity from Sugar shell, a request to that DBus service is made, which makes DBus run the previously specified executable. The executable must create a "factory service" on the DBus using the specified service name.
The most important method the factory service must provide is com.redhat.Sugar.ActivityFactory.create() which spawns an activity instance. Each activity instance has a unique activity_id which is passed as parameter to the create() method.
When the last activity instance exits, the factory service should quit.
Methods
These methods were collected by introspection on the DBus
Interface com.redhat.Sugar.ActivityFactory
/my/organization/MyActivity com.redhat.Sugar.ActivityFactory.create()
The create() method creates a new Activity instance. That instance is exposed on the DBus as /org/laptop/Activity/123456 where the number 123456 is the instance's top-level window XID.
Interface org.laptop.Activity
An activity instance needs to support the following methods:
/org/laptop/Activity/123456 org.laptop.Activity.get_id()
Get the activity identifier as passed into create() (e.g., 6f7f3acacca87886332f50bdd522d805f0abbf1f).
/org/laptop/Activity/123456 org.laptop.Activity.get_service_name()
Get the activity service name (e.g., my.organization.MyActivity).
/org/laptop/Activity/123456 org.laptop.Activity.share()
Called by the shell to request the activity to share itself on the network.
/org/laptop/Activity/123456 org.laptop.Activity.get_shared()
Returns True if the activity is shared on the mesh.
/org/laptop/Activity/123456 org.laptop.Activity.set_active(active)
Activate or passivate an activity. Passive activities must release resources like sound, camera etc.
/org/laptop/Activity/123456 org.laptop.Activity.execute(cmd, args[])
Optional - execute a command defined in the activity, answer True on success. might be deprecated soon
Signals
todo
Example
[Activity] name = My Activity activity_version = 1 host_version = 1 service_name = my.organization.MyActivity icon = activity-my exec = myactivityfactory show_launcher = yes
Signal /org/freedesktop/DBus org.freedesktop.DBus.NameAcquired(':1.23')
Signal /org/freedesktop/DBus org.freedesktop.DBus.NameAcquired('my.organization.MyActivity')
MethodCall /my/organization/MyActivity org.freedesktop.DBus.Introspectable.Introspect()
MethodCall /my/organization/MyActivity com.redhat.Sugar.ActivityFactory.create(activity_id='6f7f3acacca87886332f50bdd522d805f0abbf1f')
this is as far as I got now ... what needs to happen next? I'll find out ... -- Bert