Development Team/Almanac/lang-es
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Sugar Almanac for Developers |
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Development Team/Almanac Main Page Package: sugar |
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Package: sugar.activity |
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Package: sugar.graphics |
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Package: sugar.datastore |
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Logging |
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Notes on using Python Standard Logging |
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Internationalization |
¿Cómo puedo obtener ayuda adicional más allá de este almanaque?
- ¿Quieres comenzar con los básico del desarrollo para Sugar? Puedes visitar el Activity Handbook de OLPC Austria (Ten en cuenta que este manual fue actualizado por última vez en mayo del 2008, las capturas de tienen el diseño pre-8.2. En términos de código en sí, las cosas deberían funcionar como están descriptas. Si encuentra algún problema por favor póngase en contacto con ChristophD.)
- Ver también Development Team/Almanac/Code Snippets
Ahora, vamos con el almanaque actual...
¿Dónde puedo ver los cambios de la API?
API changes between OLPC releases can be seen here: API Changes
Comenzando
¿Cómo estructuro mis archivos para que sean una actividad de válido en Sugar?
Puedes encontrar información sobre la estructura de la actividad aquí: Activity Bundles
¿Cómo puedo hacer un icono para mi actividad?
La información sobre lo que debe hacer se puede encontrar aquí: Making Icons
Paquete: sugar
Paquete: sugar.activity
Paquete: sugar.datastore
Paquete: sugar.graphics
Paquete: sugar.presence
Clipboard
- Notas sobre el uso del módulo Clipboard de GTK
Logging
- sugar.logger
- Notas sobre el uso del standard de Logging en Python
Internacionalización
Texto y gráficos para las actividades de Sugar
¿Cómo puedo crear un cuadro de texto para la edición de código?
Puedes usar gtksourceview2
import gtk
import gtksourceview2
from sugar.graphics import style
...
# Configuramos el buffer
buffer = gtksourceview2.Buffer()
if hasattr(buffer, 'set_highlight'): # handle different API versions
buffer.set_highlight(True)
else:
buffer.set_highlight_syntax(True)
# Configuramos el tipo MIME para el buffer
lang_manager = gtksourceview2.language_manager_get_default()
if hasattr(lang_manager, 'list_languages'): # again, handle different APIs
langs = lang_manager.list_languages()
else:
lang_ids = lang_manager.get_language_ids()
langs = [lang_manager.get_language(lang_id)
for lang_id in lang_ids]
for lang in langs:
for m in lang.get_mime_types():
if m == mime_type: # <-- this is the mime type you want
buffer.set_language(lang)
# Establecemos el objeto para la vista, usarlo como gtk.TextView
view = gtksourceview2.View(buffer)
view.set_size_request(300, 450)
view.set_editable(True)
view.set_cursor_visible(True)
view.set_show_line_numbers(True)
view.set_wrap_mode(gtk.WRAP_CHAR)
view.set_right_margin_position(80)
#view.set_highlight_current_line(True) #FIXME: Ugly color
view.set_auto_indent(True)
view.modify_font(pango.FontDescription("Monospace " +
str(style.FONT_SIZE)))
...
Para agregar texto al buffer:
buffer.set_text(text)
Para obtener todo el texto:
text = buffer.get_text(buffer.get_start_iter(), buffer.get_end_iter())
Probablemente quieras poner la view(vista) en un gtk.ScrolledWindow
sw = gtk.ScrolledWindow() sw.add(view) sw.set_policy(gtk.POLICY_AUTOMATIC, gtk.POLICY_AUTOMATIC)
y agregar el el objeto sw en vez de la view(vista).
Puedes encotnrar más en el código fuete de Pippyy en jarabe.view.sourceview.
Audio y Video
Ratón
¿Cómo puedo cambiar el cursor del ratón por el cursor de espera en mi actividad?
En la subclase de tu actividad:
self.window.set_cursor( gtk.gdk.Cursor(gtk.gdk.WATCH) )
y para volver al que está por defecto:
self.window.set_cursor( None );
¿Cómo puedo rastrear la posición del ratón?
Existen varias razones por las que te puede interesar controlar la posición del ratón, que van desde el entretenimiento ([[1]]) a lo funcional (ocultar ciertas ventanas cuando el ratón no se ha movido por un par de segundos y volver a hacer aparecer esos elementos cuando este se mueva nuevamente). Esta es una manera en la cual se puede implementar esta funcionalidad:
... self.hideWidgetsTime = time.time() self.mx = -1 self.my = -1 self.HIDE_WIDGET_TIMEOUT_ID = gobject.timeout_add( 500, self.mouseMightHaveMovedCb ) def _mouseMightHaveMovedCb( self ): x, y = self.get_pointer() passedTime = 0 if (x != self.mx or y != self.my): self.hideWidgetsTime = time.time() if (self.hiddenWidgets): self.showWidgets() self.hiddenWidgets = False else: passedTime = time.time() - self.hideWidgetsTime if (passedTime >= 3): if (not self.hiddenWidgets): self.hideWidgets() self.hiddenWidgets = True self.mx = x self.my = y return True
Varios
Las tareas que aparecen más abajo son técnicas útiles que he encontrado mientras escribía código y documentación para esta referencia. No ha sido categorizadas aún.
¿Cómo se si mi actividad está "activa" o no?
Puedes configurar un evento usando la constante VISIBILITY_NOTIFY_MASK para saber cuando se cambia la visibilidad. Luego en el callback para este evento lo que debes hacer es comprar el estado del evento con las variables gtk definidas para la visibilidad de tu actividad. Puedes ver la sección de Constantes de Estado de Visibilidad de GDK gtk.gdk.Constants para más información.
# Notify when the visibility state changes by calling self.__visibility_notify_cb
# (PUT THIS IN YOUR ACTIVITY CODE - EG. THE __init__() METHOD)
self.add_events(gtk.gdk.VISIBILITY_NOTIFY_MASK)
self.connect("visibility-notify-event", self.__visibility_notify_cb)
...
# Callback method for when the activity's visibility changes
def __visibility_notify_cb(self, window, event):
if event.state == gtk.gdk.VISIBILITY_FULLY_OBSCURED:
print "I am not visible"
elif event.state in [gtk.gdk.VISIBILITY_UNOBSCURED, gtk.gdk.VISIBILITY_PARTIAL]:
print "I am visible"
¿Cómo puedo obtener la cantidad de espacio libre disponible dentro del directorio /home?
La siguiente función usa el módulo statvfs. El código siguiente muestra cómo obtener la cantidad total de espacio libre en /home.
#### Método getFreespaceKb: devuelve el espacio disponible en kilobytes.
def getFreespaceKb(self):
stat = os.statvfs("/home")
freebytes = stat[statvfs.F_BSIZE] * stat[statvfs.F_BAVAIL]
freekb = freebytes / 1024
return freekb
Ten en cuenta que asumir cosas acerca de "/home" no es una buena idea, es mejor usar os.environ['HOME']. Rainbow pondrá los archivos actuales en otros lugares, algunos en el ramdisk, otros en la flash.
Note, however, that assuming anything about "/home" is a bad idea, better use os.environ['HOME'] instead. Rainbow will put your actual files elsewhere, some on ramdisks, some on flash. Ten claro que espacio libre en el sistema de archivos realmente te importa.
How do I know whether my activity is running on a physical XO?
Sugar runs on ordinary computers as well as on XO's. While your activity is typically going to be run on a real XO, some people will indeed run it elsewhere. Normally you shouldn't write your activity to care whether it's on an XO or not. If for some odd reason, you need to care, 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. [1] [2]
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')
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.
import os
...
_logger.debug(os.environ['LANG'])
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 regularly update the time displayed on a pango layout object.
#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)
How do I update the current build version of code that is running on my XO?
There are several pages that give you instructions on how to install/update your current build.
- If you already have a working build installed and an internet connection, first try olpc:olpc-update.
- If that doesn't work, you can look at instructions for an olpc:Activated upgrade that can be done via USB] boot.
As the instructions on the pages linked above note, make sure to install your activities separately after you have upgraded to a specific base build.
I am developing on an XO laptop, but my keyboard and language settings are not ideal. How can I change them?
Internationalized laptops will often have settings that might slow you down while developing. To change around the language settings so you can better understand environment messages, use the olpc:Sugar Control Panel
Keyboard settings on internationalized laptops[3] can also be suboptimal, especially as characters like "-" and "/" are in unfamiliar positions. You can use the setxkbmap command in the olpc:Terminal Activity to reset the type of keyboard input used and then attach a standard U.S. keyboard that will allow you to type normally. The command below sets the keyboard to the US mapping (it will reset to the default internationalized mapping upon restart).
setxkbmap us
My Python activity wants to use threads; how do I do that?
A question that has been answered with limited success is which threading patterns are most appropriate for use in Sugar. The following pattern of code to work fine in basic instances:
#### Method: __init__, initialize this AnnotateActivity instance
def __init__(self, handle):
...
self.sample_thread = Thread(target=self.announce_thread, args=())
self.sample_thread.setDaemon(0)
self.sample_thread.start()
...
def announce_thread(self):
while (self.Running):
time.sleep(1)
print "thread running"
self._update_chat_text("Thread", "In here")
This is the basic series of steps that most online documentation on python suggests to use when trying to work with threads in python. The problem is that it is unclear how this pattern relates to code that worked in the SimCity activity:
import gobject gobject.threads_init() #import dbus.mainloop.glib #dbus.mainloop.glib.threads_init()
It should be noted that in the SimCity activity the pygame sound player would not produce sound reliably unless this setup was done.
Should the two patterns always be used in tandem? It seems that the latter code is mainly to initiate gobject and other libraries to work with threading, but it is unclear what restrictions there are with using threading with these libraries. Does one take precedence over the other? It is not clear if there is any problem with using the standard python threading code on the sugar technology stack.
In fact, experiments with threading on sugar leads to several different problems. For one thing, thread termination was tricky - using the can_close() method for sugar activities to terminate an activity only killed threads in some circumstances. It did not properly handle terminating threads in the case of CTRL-C or terminal interrupts. You can try to catch signals (SIGINT, SIGTERM or SIGHUP), but you will still be running in to errors in terminating child threads using these as well.
Another set of errors with threading comes up when trying to combine with stream tubes. The bottom line is that it is unclear what the scope of threading in a Sugar activity should be - should it simply work if you do the standard python threading pattern, is the use of the glib.threads_init and gobject.threads_init calls necessary, are there other interactions with threads and dbus that need to be accounted for? With more clarity from sugar developers on how the platform envisions threading to work in an activity, we can be more comfortable writing entries in the Almanac to help developers write error-free code.
How do I customize the title that is displayed for each instance of my activity?
By default, activity titles are just the generic activity names that you specify in your activity.info file. In some applications, you may want the activity title to be more dynamic.
For example, it makes sense to set the title for different browser sessions to the active web page being visited. That way, when you look back in the journal at the different browser sessions you have run in the previous few days, you can identify unique sessions based on the website you happened to be visiting at the time.
The code below shows how you can set the metadata for your activity to reflect a dynamic title based on whatever session criteria you feel is important. This example is adapted from the Browse activity, which sets activity instance titles based on the title of the current web page being visited.
if self.metadata['mime_type'] == 'text/plain':
if not self._jobject.metadata['title_set_by_user'] == '1':
if self._browser.props.title:
# Set the title of this activity to be the current
# title of the page being visited by the browser.
self.metadata['title'] = self._browser.props.title
What packages are available on sugar to support game development?
If your activity will require tools that are typically needed to develop robust and clean video games, then you should utilize the pygame package. It can be readily imported into any activity:
import pygame ...
How do I detect when one of the game buttons on the laptop have been pressed?
The laptop game buttons (the circle, square, x, and check buttons next to the LCD) are encoded as page up, home, page down and end respectively. So, you can detect their press by listening for these specific events. For example, the code below listens for button presses and then just writes to an output widget which button was pressed.
...
#### Initialize this activity.
def __init__(self, handle):
...
self.connect('key-press-event', self._keyPressCb)
...
#### Method _keyPressCb, which catches any presses of the game buttons.
def _keyPressCb(self, widget, event):
keyname = gtk.gdk.keyval_name(event.keyval)
if (keyname == 'KP_Page_Up'):
self._chat += "\nCircle Pressed!"
self._chat_buffer.set_text(self._chat)
elif (keyname == 'KP_Page_Down'):
self._chat += "\nX Pressed!"
self._chat_buffer.set_text(self._chat)
elif (keyname == 'KP_Home'):
self._chat += "\nSquare Pressed!"
self._chat_buffer.set_text(self._chat)
elif (keyname == 'KP_End'):
self._chat += "\nCheck Pressed!"
self._chat_buffer.set_text(self._chat)
return False
How do I detect if one of the joystick buttons has been pressed?
This is the same process as detecting game buttons, except with different names for the keys. Again, you listen for "key-press-event" signals and then in your callback you check to see if the pressed button was one of the joystick keys.
#### Initialize this activity.
def __init__(self, handle):
...
self.connect('key-press-event', self._keyPressCb)
...
#### Method _keyPressCb, which catches any presses of the game buttons.
def _keyPressCb(self, widget, event):
keyname = gtk.gdk.keyval_name(event.keyval)
if (keyname == 'KP_Up'):
self._chat += "\nUp Pressed!"
self._chat_buffer.set_text(self._chat)
elif (keyname == 'KP_Down'):
self._chat += "\nDown Pressed!"
self._chat_buffer.set_text(self._chat)
elif (keyname == 'KP_Left'):
self._chat += "\nLeft Pressed!"
self._chat_buffer.set_text(self._chat)
elif (keyname == 'KP_Right'):
self._chat += "\nRight Pressed!"
self._chat_buffer.set_text(self._chat)
return False
How do i remove an specific button from the toolbar?
This is an example of the share button is removed:
activity_toolbar = toolbox.get_activity_toolbar()
activity_toolbar.remove(activity_toolbar.share)
activity_toolbar.share = None