Hello,
I was wondering what would be a good way to have a Label showing the
content of a variable, and updating automatically when the variable
changes. I made something like this but I would love to hear if you have
something better for me.
import cocos
from cocos.director import director
import pyglet
class Observable(pyglet.event.EventDispatcher):
"""
A value that will fire an on_change event when its value
is changed.
"""
_value = 0
def __init__(self, value, *args, **kwargs):
super(Observable, self).__init__(*args, **kwargs)
self.value = value
def _set_value(self, new_value):
self._value = new_value
self.dispatch_event("on_change", self.value)
value = property(lambda self: self._value, _set_value)
Observable.register_event_type("on_change")
class TestLayer(cocos.layer.Layer):
"""
The layer containing the timer
"""
def __init__(self):
super( TestLayer, self ).__init__()
self.timer = Observable(0)
@self.timer.event
def on_change(timer):
self.timer_label.element.text = "Time: {}s".format(timer)
self.timer_label = cocos.text.Label("Time:
{}s".format(self.timer.value),
position=(100, 100),
font_size=20)
self.add(self.timer_label)
self.schedule_interval(self.increase_timer, 1)
def increase_timer(self, dt):
self.timer.value += 1
if __name__ == "__main__":
# director init takes the same arguments as pyglet.window
director.init(width=800, height=600, do_not_scale=True)
director.run( cocos.scene.Scene( TestLayer() ) )
What I don't like too much with this method is that I have to reference the
timer.value to manipulate my variable, instead of having just a timer
variable.
Another solution I had, inspired by CocosNode make_property function was to
create properties with the setter calling a callback.
import cocos
from cocos.director import director
import pyglet
class TestLayer(cocos.layer.Layer):
"""
The layer containing the timer
"""
def __init__(self):
super( TestLayer, self ).__init__()
self.timer_label = cocos.text.Label("Time: 0s", # Problem, I
cannot yet reference self.timer
position=(100, 100),
font_size=20)
self.add(self.timer_label)
self.timer = 0 # Problem: if I set this before creating the label,
on_timer is called and self.timer_label does not yet exist
self.schedule_interval(self.increase_timer, 1)
def increase_timer(self, dt):
self.timer += 1
def on_timer(self, value):
self.timer_label.element.text = "Time: {}s".format(value)
def make_property(attr):
def set_attr():
def inner(self, value):
setattr(self, "_"+attr, value)
#Call the function on_attributename passing the new value
as arg.
getattr(self, "on_" + attr)(value)
return inner
def get_attr():
def inner(self):
return getattr(self, "_"+attr)
return inner
return property(
get_attr(),
set_attr())
timer = make_property("timer")
if __name__ == "__main__":
# director init takes the same arguments as pyglet.window
director.init(width=800, height=600, do_not_scale=True)
director.run( cocos.scene.Scene( TestLayer() ) )
As I wrote in the code, this leads some problem of setting first the timer
property or creating first the label.
Thanks for your comments and suggestions!
Dan.
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