Python Inheritence Help

Tue, 01 Dec 2009 13:13:10 -0700

I have a simple button class to make buttons

from graphics import *

class Button:

    """A button is a labeled rectangle in a window.
    It is activated or deactivated with the activate()
    and deactivate() methods. The clicked(p) method
    returns true if the button is active and p is inside it."""

    def __init__(self, win, center, width, height, label):
        """ Creates a rectangular button, eg:
        qb = Button(myWin, Point(30,25), 20, 10, 'Quit') """ 

        w,h = width/2.0, height/2.0
        x,y = center.getX(), center.getY()
        self.xmax, self.xmin = x+w, x-w
        self.ymax, self.ymin = y+h, y-h
        p1 = Point(self.xmin, self.ymin)
        p2 = Point(self.xmax, self.ymax)
        self.rect = Rectangle(p1,p2)
        self.rect.setFill('lightgray')
        self.rect.draw(win)
        self.label = Text(center, label)
        self.label.draw(win)
        self.deactivate()

    def clicked(self, p):
        "Returns true if button active and p is inside"
        return self.active and \
               self.xmin <= p.getX() <= self.xmax and \
               self.ymin <= p.getY() <= self.ymax

    def getLabel(self):
        "Returns the label string of this button."
        return self.label.getText()

    def activate(self):
        "Sets this button to 'active'."
        self.label.setFill('black')
        self.rect.setWidth(2)
        self.active = True

    def deactivate(self):
        "Sets this button to 'inactive'."
        self.label.setFill('darkgrey')
        self.rect.setWidth(1)
        self.active = False

and I wanted to make a CustomButton class which inherited Button, except with a black button and green text, I tried this

class CustomButton(Button):
	def __init__(self, win, center, width, height, label):
		        self.rect.setFill('black')
			self.label.setFill('green')

But I get this error:

Traceback (most recent call last):
File "calc.pyw", line 104, in <module>
theCalc = Calculator()
File "calc.pyw", line 21, in __init__
self.__createButtons()
File "calc.pyw", line 37, in __createButtons
self.buttons.append(CustomButton(self.win,Point(cx ,cy),.75,.75,label))
File "calc.pyw", line 11, in __init__
self.rect.setFill('black')
AttributeError: CustomButton instance has no attribute 'rect'

Do I need to rewrite the entire __init__ to change this?

Re: Python Inheritence Help

Tue, 01 Dec 2009 18:17:28 -0700

actually came up with this:

class CustomButton(Button):
	def changeColors(self,label,bg,outline):
		self.label.setFill(label)
		self.rect.setFill(bg)
		self.rect.setOutline(outline)

and then just change it after making the button objects

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