Activity tutorial

The tutorial explains step by step how to create the Hello World activity bundle.

Create the bundle directory structure.

hello.activity
hello.activity/activity

Write the activity.info file, to describe your bundle in the activity sub-directory (i.e. hello.activity/activity/activity.info). The Activity Bundles specification explain in detail the meaning of each field.

[Activity]
name = HelloWorld
service_name = com.ywwg.HelloWorldActivity
class = HelloWorldActivity.HelloWorldActivity
icon = activity-helloworld
activity_version = 1
show_launcher = yes

Design an icon for your activity, according to the icon format and place it in the activity sub-directory. The file name should match the one specified in the info "activity-helloworld.svg".

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
 "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd" [
  <!ENTITY fill_color "#FFFFFF">
  <!ENTITY stroke_color "#000000">
]>
<svg xmlns="http://www.w3.org/2000/svg" width="50" height="50">
  <rect x="1" y="1" width="48" height="48"
  style="fill:&fill_color;;stroke:&stroke_color;;stroke-width:2"/>
</svg>

Write the setup.py script in the top level directory (i.e. hello.activity/setup.py), which in most cases will look like this:

#!/usr/bin/env python
from sugar.activity import bundlebuilder
if __name__ == "__main__":
    bundlebuilder.start()

Code your activity. Module and class names should match those specified in the exec field of the info. That is, the exec must be specified as a direct dotted path to the class name. The top-level is the hello.activity directory, so for the activity.info file above, we specify a top-level module named HelloWorldActivity.HelloWorldActivity (please note that the use of uppercase names in module names is considered poor Python style, feel free to use an activity name with more standard style names).

import logging
from sugar.activity import activity

import sys, os
import gtk

class HelloWorldActivity(activity.Activity):
    # This is a callback function. The data arguments are ignored
    # in this example. More on callbacks below.
    def hello(self, widget, data=None):
        logging.info('Hello World')

    def __init__(self, handle):
        activity.Activity.__init__(self, handle)

        # Creates a new button with the label "Hello World".
        self.button = gtk.Button("Hello World")

        # When the button receives the "clicked" signal, it will call the
        # function hello() passing it None as its argument.  The hello()
        # function is defined above.
        self.button.connect("clicked", self.hello, None)

        # This packs the button into ourselves (a Sugar window).
        self.add(self.button)

        # The final step is to display this newly created widget.
        self.button.show()

        self.set_title('Hello World')

Create a MANIFEST, containing the list of the files to include in the package. (Note: Be sure not to leave blank lines at the end of the file.)

HelloWorldActivity.py

Your directory structure should now look like this:

hello.activity/
hello.activity/setup.py
hello.activity/activity
hello.activity/activity/activity.info
hello.activity/activity/activity-helloworld.svg
hello.activity/HelloWorldActivity.py
hello.activity/MANIFEST

Setup your bundle for development

./setup.py dev

If you now run sugar the activity icon should be visible on the frame. You can edit the code in your bundle directory, it will be picked up when sugar is restarted.

Create a xo package to distribute your bundle. (An xo file is essentially a zip file built from the MANIFEST with some extra metadata, like a JAR file. It also has some localization ability, and in the future we expect to be able to sign these too.)

 ./setup.py dist

To install the xo on a laptop you can use the installer script.

 sugar-install-bundle HelloWorld-1.xo

XXX Explain what the -1 suffix means.