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→Package: sugar.presence
{{Sugar Almanac TOC}}
= How do I get additional help beyond this almanac? =
* Looking to get started with the basics of sugar development? Check out Christoph Derndorfer's [http://www.olpcaustria.org/mediawiki/index.php/Activity_handbook Activity Handbook].
* See also [[Sugar Code Snippets]]
Now, on to the actual almanac ...
= Package: sugar =
* [[sugar.env]]
* [[sugar.profile]]
* [[sugar.mime]]
* [[sugar.logger]]
= Package: sugar.activity =
* [[sugar.activity.activity]]
* [[sugar.activity.activityfactory]]
* [[sugar.activity.registry]]
= Package: sugar.datastore =
* [[sugar.datastore.datastore]]
= Package: sugar.graphics =
* [[sugar.graphics.alert]]
* [[sugar.graphics.icon]]
* [[sugar.graphics.notebook]]
* [[sugar.graphics.toolbutton]]
* [[sugar.graphics.toolbox]]
= Package: sugar.presence =
* [[sugar.presence.activity]]
* [[sugar.presence.buddy]]
* [[sugar.presence.presenceservice]]
= Clipboard =
* Notes on using [[GTK's Clipboard Module in Sugar]]
= Logging =
* [[sugar.logger]]
* Notes on using [[Python Standard Logging in Sugar]]
= Internationalization =
[[Internationalization in Sugar]]
= Text and Graphics for Sugar Activities =
* [[Pango]]
= MISCELLANEOUS =
The tasks below are random useful techniques that have come up as I write code and documentation for this reference. They have yet to be categorized, but will be as a sufficient set of related entries are written.
=== How do I know when my activity is "active" or not? ===
You can set an event using the VISIBILITY_NOTIFY_MASK constant in order to know when your activity changes visibility. Then in the callback for this event, you simply compare the event's state to gtk-defined variables for activity visibility. See the [http://www.pygtk.org/docs/pygtk/gdk-constants.html#gdk-visibility-state-constants GDK Visibility State Constants] section of gtk.gdk.Constants for more information.
<pre>
#Notify when the visibility state changes by calling self._visibleNotifyCb
#(PUT THIS IN YOUR ACTIVITY CODE - EG. THE __init__() METHOD)
self.add_events(gtk.gdk.VISIBILITY_NOTIFY_MASK)
self.connect("visibility-notify-event", self._visibleNotifyCb)
...
#Callback method for when the activity's visibility changes
def _visibleNotifyCb(self, widget, event):
if (event.state == gtk.gdk.VISIBILITY_FULLY_OBSCURED):
print "I am not visible"
elif (event.state == gtk.gdk.VISIBILITY_UNOBSCURED):
print "I am visible"
</pre>
=== How do I get the amount of free space available on disk under the /home directory tree? ===
The following function uses the [http://docs.python.org/lib/module-statvfs.html statvfs] module. The following code demonstrates how to get the total amount of free space under /home.
<pre>
#### Method: getFreespaceKb, returns the available freespace in kilobytes.
def getFreespaceKb(self):
stat = os.statvfs("/home")
freebytes = stat[statvfs.F_BSIZE] * stat[statvfs.F_BAVAIL]
freekb = freebytes / 1024
return freekb
</pre>
=== How do I know whether my activity is running on a physical XO? ===
While your activity is typically going to be run on a real XO, there might be circumstances (such as for development through sugar-jhbuild) that you will not be running on an XO machine. The easiest way to tell if you are on a physical XO is to check whether /sys/power/olpc-pm, an essential power management file for the XO, exists. <ref>[http://lists.laptop.org/pipermail/devel/2008-June/015923.html reliably detecting if running on an XO]</ref> <ref>[http://wiki.laptop.org/go/Power_Management_Interface OLPC Power Management Interface]</ref>
<pre>
import os
...
#Print out a boolean value that tells us whether we are on an XO or not.
print os.path.exists('/sys/power/olpc-pm')
</pre>
=== How do I know the current language setting on my XO? ===
The system variable 'LANG' tells you which language is currently active on the XO. The following code shows how to look at the value of this variable.
<pre>
import os
...
_logger.debug(os.environ['LANG'])
</pre>
=== How do I repeatedly call a specific method after N number of seconds? ===
The gobject.timeout_add() function allows you to invoke a callback method after a certain amount of time. If you want to repeatedly call a method, simply keep invoking the gobject.timeout_add function in your callback itself. The code below is a simple example, where the callback function is named repeatedly_call. Note that the timing of the callbacks are approximate. To get the process going, you should make an initial call to repeatedly_call() somewhere in your code.
You can see a more substantive example of this pattern in use when we [[Pango#How_do_I_dynamically_set_the_text_in_a_pango_layout.3F | regularly update the time displayed on a pango layout object]].
<pre>
#This method calls itself ROUGHLY every 1 second
def repeatedly_call(self):
now = datetime.datetime.now()
gobject.timeout_add(self.repeat_period_msec, self.repeatedly_update_time)
</pre>
=== How do I update the current build version of code that is running on my XO? ===
Use [http://wiki.laptop.org/go/Olpc-update olpc-update]
= Notes =
<references />
= How do I get additional help beyond this almanac? =
* Looking to get started with the basics of sugar development? Check out Christoph Derndorfer's [http://www.olpcaustria.org/mediawiki/index.php/Activity_handbook Activity Handbook].
* See also [[Sugar Code Snippets]]
Now, on to the actual almanac ...
= Package: sugar =
* [[sugar.env]]
* [[sugar.profile]]
* [[sugar.mime]]
* [[sugar.logger]]
= Package: sugar.activity =
* [[sugar.activity.activity]]
* [[sugar.activity.activityfactory]]
* [[sugar.activity.registry]]
= Package: sugar.datastore =
* [[sugar.datastore.datastore]]
= Package: sugar.graphics =
* [[sugar.graphics.alert]]
* [[sugar.graphics.icon]]
* [[sugar.graphics.notebook]]
* [[sugar.graphics.toolbutton]]
* [[sugar.graphics.toolbox]]
= Package: sugar.presence =
* [[sugar.presence.activity]]
* [[sugar.presence.buddy]]
* [[sugar.presence.presenceservice]]
= Clipboard =
* Notes on using [[GTK's Clipboard Module in Sugar]]
= Logging =
* [[sugar.logger]]
* Notes on using [[Python Standard Logging in Sugar]]
= Internationalization =
[[Internationalization in Sugar]]
= Text and Graphics for Sugar Activities =
* [[Pango]]
= MISCELLANEOUS =
The tasks below are random useful techniques that have come up as I write code and documentation for this reference. They have yet to be categorized, but will be as a sufficient set of related entries are written.
=== How do I know when my activity is "active" or not? ===
You can set an event using the VISIBILITY_NOTIFY_MASK constant in order to know when your activity changes visibility. Then in the callback for this event, you simply compare the event's state to gtk-defined variables for activity visibility. See the [http://www.pygtk.org/docs/pygtk/gdk-constants.html#gdk-visibility-state-constants GDK Visibility State Constants] section of gtk.gdk.Constants for more information.
<pre>
#Notify when the visibility state changes by calling self._visibleNotifyCb
#(PUT THIS IN YOUR ACTIVITY CODE - EG. THE __init__() METHOD)
self.add_events(gtk.gdk.VISIBILITY_NOTIFY_MASK)
self.connect("visibility-notify-event", self._visibleNotifyCb)
...
#Callback method for when the activity's visibility changes
def _visibleNotifyCb(self, widget, event):
if (event.state == gtk.gdk.VISIBILITY_FULLY_OBSCURED):
print "I am not visible"
elif (event.state == gtk.gdk.VISIBILITY_UNOBSCURED):
print "I am visible"
</pre>
=== How do I get the amount of free space available on disk under the /home directory tree? ===
The following function uses the [http://docs.python.org/lib/module-statvfs.html statvfs] module. The following code demonstrates how to get the total amount of free space under /home.
<pre>
#### Method: getFreespaceKb, returns the available freespace in kilobytes.
def getFreespaceKb(self):
stat = os.statvfs("/home")
freebytes = stat[statvfs.F_BSIZE] * stat[statvfs.F_BAVAIL]
freekb = freebytes / 1024
return freekb
</pre>
=== How do I know whether my activity is running on a physical XO? ===
While your activity is typically going to be run on a real XO, there might be circumstances (such as for development through sugar-jhbuild) that you will not be running on an XO machine. The easiest way to tell if you are on a physical XO is to check whether /sys/power/olpc-pm, an essential power management file for the XO, exists. <ref>[http://lists.laptop.org/pipermail/devel/2008-June/015923.html reliably detecting if running on an XO]</ref> <ref>[http://wiki.laptop.org/go/Power_Management_Interface OLPC Power Management Interface]</ref>
<pre>
import os
...
#Print out a boolean value that tells us whether we are on an XO or not.
print os.path.exists('/sys/power/olpc-pm')
</pre>
=== How do I know the current language setting on my XO? ===
The system variable 'LANG' tells you which language is currently active on the XO. The following code shows how to look at the value of this variable.
<pre>
import os
...
_logger.debug(os.environ['LANG'])
</pre>
=== How do I repeatedly call a specific method after N number of seconds? ===
The gobject.timeout_add() function allows you to invoke a callback method after a certain amount of time. If you want to repeatedly call a method, simply keep invoking the gobject.timeout_add function in your callback itself. The code below is a simple example, where the callback function is named repeatedly_call. Note that the timing of the callbacks are approximate. To get the process going, you should make an initial call to repeatedly_call() somewhere in your code.
You can see a more substantive example of this pattern in use when we [[Pango#How_do_I_dynamically_set_the_text_in_a_pango_layout.3F | regularly update the time displayed on a pango layout object]].
<pre>
#This method calls itself ROUGHLY every 1 second
def repeatedly_call(self):
now = datetime.datetime.now()
gobject.timeout_add(self.repeat_period_msec, self.repeatedly_update_time)
</pre>
=== How do I update the current build version of code that is running on my XO? ===
Use [http://wiki.laptop.org/go/Olpc-update olpc-update]
= Notes =
<references />