My objective is to add a vertical scroll bar to a frame which has several labels in it. The scroll bar should automatically enabled as soon as the labels inside the frame exceed the height of the frame. After searching through, I found this useful post. Based on that post I understand that in order to achieve what i want, (correct me if I am wrong, I am a beginner) I have to create a
Frame first, then create a
Canvas inside that frame and stick the scroll bar to that frame as well. After that, create another frame and put it inside the canvas as a window object. So, I finally come up with this:
from Tkinter import * def data(): for i in range(50): Label(frame,text=i).grid(row=i,column=0) Label(frame,text="my text"+str(i)).grid(row=i,column=1) Label(frame,text="..........").grid(row=i,column=2) def myfunction(event): canvas.configure(scrollregion=canvas.bbox("all"),width=200,height=200) root=Tk() sizex = 800 sizey = 600 posx = 100 posy = 100 root.wm_geometry("%dx%d+%d+%d" % (sizex, sizey, posx, posy)) myframe=Frame(root,relief=GROOVE,width=50,height=100,bd=1) myframe.place(x=10,y=10) canvas=Canvas(myframe) frame=Frame(canvas) myscrollbar=Scrollbar(myframe,orient="vertical",command=canvas.yview) canvas.configure(yscrollcommand=myscrollbar.set) myscrollbar.pack(side="right",fill="y") canvas.pack(side="left") canvas.create_window((0,0),window=frame,anchor='nw') frame.bind("<Configure>",myfunction) data() root.mainloop()
anchor='nw'when creating window on canvas?
Please keep your answer simple, as I am a beginner.
“Am i doing it right?Is there better/smarter way to achieve the output this code gave me?”
Generally speaking, yes, you’re doing it right. Tkinter has no native scrollable container other than the canvas. As you can see, it’s really not that difficult to set up. As your example shows, it only takes 5 or 6 lines of code to make it work — depending on how you count lines.
“Why must i use grid method?(i tried place method, but none of the labels appear on the canvas?)”
You ask about why you must use grid. There is no requirement to use grid. Place, grid and pack can all be used. It’s simply that some are more naturally suited to particular types of problems. In this case it looks like you’re creating an actual grid — rows and columns of labels — so grid is the natural choice.
“What so special about using anchor=’nw’ when creating window on canvas?”
The anchor tells you what part of the window is positioned at the coordinates you give. By default, the center of the window will be placed at the coordinate. In the case of your code above, you want the upper left (“northwest”) corner to be at the coordinate.