Handout 20

Overview

• Questions from last time
• Working with Tk continued

Working with Tk continued

• pack(). Widgets are placed in the window with the pack() command. The position of widgets is controlled by when they are packed, and by the properties that are passed to the pack() command (example, example, example).
• pack() attributes. We've already seen the -side attribute for pack(). Another set of very useful attributes include: -padx, -pady, -ipadx, and -ipady. These control how far a widget is from the edges of its container and how big it is itself (example).
• Use the packForget() method to remove an item from the window, without deleting it. Use ismapped() to see if a widget is currently displayed (example).
• Changing the text on a button or label is straightforward using the -textvariable attribute. It's a little trickier with Entry or Scrolled/Text. In these cases, you need to use the get() or delete() methods which take special indices to refer to particular places in the text, e.g. "1.0" or "0.0" for the beginning and "end" for the end. For an Entry, get() takes no arguments and the initial index seems to be "0.0". For a Text, both methods take indices as arguments, but the initial index seems to be "1.0"! (example, example).