CODEWITHSUNDEEP
pythontkinter
Vinurk
Vinurk

Reputation: 21

How to move a scrollbar automatically in tkinter?

I am making an application for chatting in tkinter. I have the scrollbar working properly. When the messages go out of the frame the scrollbar is triggered. But to automatically scroll down as new messages arrive i have added my_canvas.yview_moveto('1.0') and it scrolls automatically as expected but leaves a small gap at the end due to which the new messages are not seen as u get them but u see it after one more update. Sorry i hope i did not confuse you. Here's my full code:

from tkinter import *
from tkinter import ttk

send_y = 70

def main():

    window =Tk()
    window.geometry("780x600")
    window.configure(bg="#b3b6ba")
    window.resizable(False,False)
    window.bind('<Return>',lambda event:send())


    # create a main frame

    main_frame=Frame(window,height=565,width=780)
    main_frame.place(x=0,y=0)
    main_frame.propagate(False)

    # create a canvas

    my_canvas=Canvas(main_frame)
    my_canvas.pack(side=LEFT,fill=BOTH,expand=1)

    # Add a scrollbar

    my_scrollbar=ttk.Scrollbar(main_frame,orient=VERTICAL,command=my_canvas.yview)
    my_scrollbar.pack(side=RIGHT,fill=Y)


    # Configure the canvas

    my_canvas.configure(yscrollcommand=my_scrollbar.set)
    my_canvas.bind("<Configure>",lambda e:my_canvas.configure(scrollregion=my_canvas.bbox("all")))

    # create another frame inside the canvas

    second_frame=Frame(my_canvas,bg="pink",height=10,width=10)

    # add that frame to a window in the canvas

    my_canvas.create_window((0,0),window=second_frame,anchor="nw")

    testlabel = Label(second_frame, width=0, text="blah blah blah", anchor=NW, justify=LEFT, bg="black", fg="white",
                          padx=0, pady=0, font=('helvetica', 12), wraplength=235)

    def send():
        global send_y


        send_msgLabel = Label(second_frame, width=0, textvariable=send_msg, anchor=NW, justify=LEFT, bg="black", fg="white",
                              padx=0, pady=0, font=('helvetica', 12), wraplength=235)

        send_msg.set(msg_entry.get())
        send_msgLabel.configure(textvariable=send_msg.get())

        msg_entry.delete(0, END)

        send_msgLabel.pack()



        #send_msgLabel.place(x=0, y=send_y)
        send_y += send_msgLabel.winfo_reqheight()+10
        my_canvas.yview_moveto('1.0')

        my_canvas.configure(scrollregion=my_canvas.bbox("all"))
        #print(my_scrollbar.delta(10,20))
        #my_scrollbar.set(0,1.0)

    msg_entry = Entry(window,width=62,font=("helvetica",14))
    msg_entry.pack()
    msg_entry.place(x=10,y=565)

    send_msg=StringVar()

    send_butt=Button(text="Send",relief=GROOVE,width=9,command=send)
    send_butt.pack()
    send_butt.place(x=700,y=565)

    window.mainloop()

if __name__ == '__main__':
    main()

Please help. Output:Output screen As you can see only half of the text is visible.

Upvotes: 0

Views: 1732

Answers (1)

Thingamabobs
Thingamabobs

Reputation: 8037

Your problem is that you call

my_canvas.configure(scrollregion=my_canvas.bbox("all"))

after you scrolled all the way down. So the last Label isn't part of your current scrollregion. Update your scrollregion first and the small gap will disapear.

Also note that you should do

window.update_idletasks()

before you update your scrollregion, otherwise your last label isnt included in your bbox and your scrollregion is missing it, therefore your label is beyond the scrollregion.

Upvotes: 1

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