CODEWITHSUNDEEP
pythontkinter
killer
killer

Reputation: 382

Python Tkinter Confusion

I am new to Python and programming in general also new to stack overflow. Any help would be appreciated, I am just messing around with code for fun to get a feel for it.

My goal is to change the box from red to blue when the button is pushed. I set the var rec1c to 'red' then set it to 'blue' when the button is pushed. I ran the code and the box never turned blue. I put the print statements in to see if it changed, the box never turned blue. I am confused as to why because I kept pressing the button and the first print statement never turned back to red. the second time pressing both statements are blue i thought it would change back after thinking about689 it that's why i put those there

my questions are

Is it possible to accomplish my goal? If so how? Is there a better way to doing it than my way? also i tried putting all my code into the question but it cut a lot of it out so I deleted all but the necessary code. Assume the syntax is correct. 

class PythonTest(Frame):
def __init__(self, parent):
    Frame.__init__(self, parent)
    self.parent = parent
    self.initUI()


def initUI(self):
    self.parent.title("Python!")
    self.style = Style()
    self.style.theme_use("default")
    self.pack(fill=BOTH, expand=1)
    self.canw = 300
    self.canh = 400

    paper = Canvas(self, width=self.canw, height=self.canh)
    paper.pack()

    self.rec1c = 'red'
    self.rec1o = 'red'
    self.rec1 = paper.create_rectangle(0, 0, 300, 300, fill=self.rec1c, outline=self.rec1o)

    self.translate = Button(self, text="Change Color!", command=self.toB)
    self.translate.place(x=50, y=50)

def toB(self):
    print(self.rec1c)
    self.rec1c = 'blue'
    print(self.rec1c)
    Tk.update

Upvotes: 0

Views: 125

Answers (2)

Kenly
Kenly

Reputation: 26688

To access paper from toB() use self.paper and to change color add self.paper.itemconfig(self.rec1, fill=self.rec1c) in toB method. 

class PythonTest(Frame):
    def __init__(self, parent):
        Frame.__init__(self, parent)
        self.parent = parent
        self.initUI()


    def initUI(self):
        self.parent.title("Python!")
        #self.style = Style()
        #self.style.theme_use("default")
        self.pack(fill=BOTH, expand=1)
        self.canw = 300
        self.canh = 400

        self.paper = Canvas(self, width=self.canw, height=self.canh)
        self.paper.pack()

        self.rec1c = 'red'
        self.rec1o = 'red'
        self.rec1 = self.paper.create_rectangle(0, 0, 300, 300, fill=self.rec1c, outline=self.rec1o)

        self.translate = Button(self, text="Translate to Pig Latin", command=self.toB)
        self.translate.place(x=50, y=50)

    def toB(self):
        print(self.rec1c)
        self.rec1c = 'blue'
        print(self.rec1c)
        self.paper.itemconfig(self.rec1, fill=self.rec1c)

Upvotes: 2

Kevin
Kevin

Reputation: 76194

Changing the value of self.rec1c will not propagate any changes to canvas elements whose attributes were defined using self.rec1c. self.rec1c has a new value, but the canvas elements still happily point to the old value, and will continue to do so no matter what happens to self.rec1c.

If you want the rectangle's attributes to change, you need to change them explicitly with itemconfig.

self.paper = Canvas(self, width=self.canw, height=self.canh)
self.paper.pack()

self.rec1 = paper.create_rectangle(0, 0, 300, 300, fill="red", outline="red")

#later, in toB...

self.paper.itemconfig(self.rec1, fill="blue")

Upvotes: 0

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