PCPP1 Graphical User Interface Programming — Timed 25 Questions

Question 1

You want to create a button that closes the GUI application when clicked. Which method should you call inside the command callback?

Accepted Answer

root.destroy(). The destroy() method on the root window object terminates the Tkinter application.

Answer

root.close()

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root.exit()

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root.quit()

Question 2

When using the pack geometry manager, you want a widget to fill the available space in the parent container. Which argument for the 'fill' parameter should you use to make it expand in both horizontal and vertical directions?

Accepted Answer

fill=tk.BOTH. fill=tk.BOTH is the correct Tkinter constant to make a widget expand in both horizontal and vertical directions within its allocated space. tk.BOTH is a symbolic constant equal to the string 'both', and it is the documented value for the fill option. Combined with expand=True, the widget grows to fill the parent container.

Answer

fill='all'

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fill='both'

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fill=tk.EXPAND

Question 3

To prevent a user from editing text in a widget, which configuration option should you set?

Accepted Answer

state=tk.DISABLED. Setting 'state' to 'disabled' prevents user interaction with the widget.

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editable=False

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enabled=False

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readonly=True

Question 4

Which method on a widget instance causes it to be removed from the display, but not destroyed?

Accepted Answer

widget.pack_forget(). The pack_forget() (or grid_forget()) method hides a widget from the layout manager.

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widget.hide()

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widget.remove()

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widget.delete()

Question 5

You want to trigger a function when a user releases a key. Which event string should you use with bind()?

Accepted Answer

. The '' event is used to detect when a key is released.

Answer

<Key-Up>

Answer

Answer

<KeyUp>

Question 6

Which THREE of the following are valid Tkinter variable classes used for tracking widget states?

Accepted Answer

IntVar. IntVar (B) is a valid Tkinter variable class that holds an integer value and is commonly bound to widgets like Entry or Scale to track and synchronize their state. StringVar (D) is likewise valid, storing a string value and used with widgets such as Entry, Label, and Text to reflect widget content. BooleanVar (E) is also valid, holding a boolean (0/1) value typically linked to Checkbutton widgets to track their checked state. The unmarked options do not belong: FloatVar (A) is not a real Tkinter class (the correct one is DoubleVar), and CharVar (C) does not exist in Tkinter's variable class set.

Answer

FloatVar

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CharVar

Question 7

Which TWO of the following statements about the 'grid' geometry manager are correct?

Accepted Answer

It allows widgets to span across multiple rows or columns.. Option C is correct because the grid geometry manager supports the rowspan and columnspan options, which let a widget occupy multiple adjacent rows or columns within its parent container. Option D is correct because grid positions widgets by specifying row and column indices (e.g., grid(row=0, column=1)), optionally combined with sticky, padx, and pady for alignment and spacing. Option A is wrong because grid uses relative cell-based placement rather than absolute pixel coordinates. Option B is wrong because grid supports arbitrary numbers of rows and columns, not just a single column. Option E is wrong because Tkinter permits mixing pack and grid within the same parent as long as they are not applied to widgets sharing the same master in conflicting ways; the restriction is about consistency, not an absolute prohibition.

Answer

It requires absolute pixel positioning.

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It only supports a single column layout.

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It cannot be mixed with the pack manager in the same parent.

Question 8

Which THREE of the following are valid states for a Tkinter widget?

Accepted Answer

disabled. In Tkinter, the widget 'state' option accepts a defined set of values, and the three valid states among the choices are 'disabled' (B), 'normal' (C), and 'active' (D). 'normal' (C) is the default state in which the widget responds to user interaction, such as a button being clickable. 'disabled' (B) makes the widget unresponsive and typically renders it greyed out, preventing any user input. 'active' (D) is the state a widget enters when the mouse pointer is over it (or during certain interactions), often used to change appearance via the 'activebackground' or 'activeforeground' options. The other options are not Tkinter widget states: 'readonly' (A) is a valid state for Tkinter Entry and Text widgets but is not a general widget state value, and 'hidden' (E) is not a state at all — visibility is controlled by the pack/grid/place geometry managers or the withdraw() method, not by the state option.

Answer

readonly

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hidden

Question 9

You are building a Tkinter application and need to ensure that a Label widget expands to fill any extra horizontal space when the parent window is resized. Which configuration for the grid() layout manager achieves this?

Accepted Answer

parent.columnconfigure(0, weight=1) and widget.grid(sticky='ew'). The sticky parameter with 'ew' (east and west) ensures the widget stretches horizontally, while columnconfigure with weight > 0 allows the column to expand.

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widget.pack(fill='x', expand=True)

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widget.grid(sticky='nsew')

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widget.grid(padx=10, pady=10)

Question 10

You are implementing a GUI where a long-running calculation is performed upon clicking a button. To prevent the GUI from freezing (not responding), what is the best practice approach?

Accepted Answer

Use the threading module to run the calculation in a separate thread.. Running blocking operations in the main thread freezes the event loop; threading is required to keep the GUI responsive.

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Call root.update() inside the calculation loop.

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Increase the root.after() delay time.

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Wrap the calculation in a try-except block within the button command.

Answer

difficulty

Question 11

When binding an event to a widget using 'widget.bind('<Key>', handler)', the handler function receives an event object. How do you access the specific character pressed?

Accepted Answer

handler(event.char). The event object passed to the handler contains the 'char' attribute which holds the character pressed.

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handler(event.keysym)

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handler(event.get_char())

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handler(event.key)

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difficulty

Question 12

You are using the pack() geometry manager and want to place a frame at the bottom of the window, ensuring it stays there even when other widgets are added. Which configuration is correct?

Accepted Answer

frame.pack(side='bottom', fill='x'). In Tkinter's pack geometry manager, the side option determines which side of the container the widget is packed against. Setting side='bottom' places the frame at the bottom of the window, and fill='x' makes it stretch horizontally to fill the available width. This configuration ensures the frame stays at the bottom even when other widgets are added, because pack allocates space in the order widgets are packed.

Answer

frame.pack(anchor='s', expand=True)

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frame.pack(side='bottom', expand=False)

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difficulty

Answer

frame.grid(row=99, column=0)

Question 13

Which widget is most appropriate if you need to display a read-only multi-line block of text to the user?

Accepted Answer

Text. The Text widget is standard for multi-line text, and setting 'state' to 'disabled' makes it read-only.

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difficulty

Answer

Message

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Entry

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Label

Question 14

You want to create a Menu that contains sub-menus. Which class or method is used to add a sub-menu to an existing menu?

Accepted Answer

menu.add_cascade(). The add_cascade method is used to create a menu item that opens a sub-menu.

Answer

difficulty

Answer

menu.add_menu()

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menu.add_command()

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menu.add_submenu()

Question 15

Which TWO of the following methods are commonly used to update a Tkinter widget's state or appearance dynamically?

Accepted Answer

widget.config(state='disabled'). Option D is correct because Tkinter widgets expose the config() (aliased as configure()) method, and calling widget.config(state='disabled') dynamically changes the widget's state option at runtime, immediately updating its appearance and interactivity. Option E is correct because widget.insert(END, 'text') is the standard Tkinter method for dynamically adding content to text-bearing widgets such as Entry, Text, and Listbox, using the END index to append at the end. Options A, B, and C are not part of the Tkinter widget API: there is no rebind(), reload(), or refresh() method on standard Tkinter widgets, so they cannot be used to update a widget's state or appearance.

Answer

widget.rebind()

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widget.reload()

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widget.refresh()

Question 16

You are building a Tkinter application that uses a ttk.Treeview widget to display hierarchical data. You need to allow users to expand and collapse nodes, and you want to programmatically expand all nodes under a selected item. Which Treeview method should you use to expand a specific item and all its descendants?

Accepted Answer

treeview.item(item, open=True) combined with a recursive traversal of children. The Treeview widget does not have a single method to expand all descendants. You must use the item() method with open=True on the target item and then recursively on each child. This requires writing a loop or recursive function. Other methods like see() only scroll to an item, and expand() only affects one level. Thus, the combination of item(open=True) and recursion is necessary.

Answer

treeview.see(item)

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treeview.expand(item)

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treeview.item(item, open=True)

Question 17

You are building a Tkinter application whose main window contains a single Text widget that must resize with the window and always keep a 10-pixel margin on every side. Which combination of calls correctly binds the Text widget's size to the window while preserving the margins?

Accepted Answer

text.pack(fill=tk.BOTH, expand=True, padx=10, pady=10). The pack geometry manager with fill set to BOTH, expand enabled, and explicit padx/pady values lets the Text widget grow with the window while keeping a uniform 10-pixel margin. Other managers can also work, but they require additional configuration of weights or relative sizing to achieve the same effect, and the options that omit those steps do not satisfy the scenario.

Answer

text.grid(sticky='nsew', padx=10, pady=10) with root.rowconfigure(0, weight=1) and root.columnconfigure(0, weight=1)

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text.place(relx=0.5, rely=0.5, relwidth=1.0, relheight=1.0)

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text.pack(side=tk.LEFT, fill=tk.X, expand=True) and text.config(width=80, height=24)

Question 18

You are developing a Tkinter application that includes a menu bar with a 'File' menu. The menu contains a 'Quit' command that should terminate the application. You also want to add a keyboard shortcut (accelerator) for the 'Quit' command using the Ctrl+Q key combination. Which two of the following steps are necessary to correctly implement this? (Choose two.)

Accepted Answer

Use the add_command method with the accelerator parameter set to 'Ctrl+Q'.. To implement a keyboard shortcut for a menu command, you must both display the accelerator text using the accelerator parameter in add_command and bind the actual key event to the appropriate function. The accelerator parameter alone does not create a binding; it is purely informational. Therefore, the two necessary steps are using add_command with accelerator and binding the key event. Other options are either general menu setup or unrelated to the shortcut.

Answer

Use the command parameter of add_command to specify the function to call when the menu item is selected.

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Create a Menu widget and add it to the root window using root.config(menu=menubar).

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Set the tearoff parameter to 0 when creating the File menu.

Question 19

You are building a Tkinter preferences dialog with a Checkbutton labeled 'Enable logging'. Users report that clicking the checkbutton changes its visual state, but reading `log_var.get()` always returns the same value regardless of how many times they click. The variable was created with `log_var = tk.StringVar()` and passed to the Checkbutton via the `variable` option. What is the most likely cause?

Accepted Answer

A `BooleanVar` must be used instead of a `StringVar`, because Checkbuttons only synchronize with variables whose class matches their internal integer state.. Checkbuttons synchronize their state with a Tkinter variable through the `variable` option, writing the `onvalue` (default 1) or `offvalue` (default 0). A BooleanVar is purpose-built for this and returns True/False consistently. Using a StringVar stores the string form of the integer, which can look unchanged or behave unexpectedly in comparisons, making it the wrong variable class for a boolean toggle.

Answer

The Checkbutton must be packed or gridded before the variable is created, otherwise the `variable` link is never established.

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The `variable` option is ignored for Checkbuttons unless the widget is also given a `command` callback that manually calls `set()`.

Answer

The Checkbutton's `onvalue` and `offvalue` options must be set to the strings 'True' and 'False' for the state to be reflected in the variable.

Question 20

You are writing a Tkinter dialog that must open a file picker limited to PNG images and return the chosen path. A colleague's draft uses `tkinter.filedialog.askopenfilename(filetypes=[('PNG', '*.png')])`. During testing, users can still select a .txt file by typing its name into the filename box. What is the correct explanation and adjustment?

Accepted Answer

The behavior is expected: `filetypes` filters what is displayed but does not block manual entry, so the application must re-check the returned path's extension after the dialog closes.. Native file dialogs treat `filetypes` as a display filter only, so users can still type a filename with a different extension. The application must validate the returned path after the dialog closes, for example by checking the extension with `os.path.splitext` and rejecting non-PNG selections. This is the correct, portable way to enforce file-type restrictions in Tkinter.

Answer

The `filetypes` list should be passed as a tuple of tuples with the pattern first and description second, e.g. `(('*.png', 'PNG'),)`, to activate hard filtering.

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The `filetypes` option is only a display filter; you must validate the returned extension in code or use `askopenfilename` with a custom `validatecommand` to enforce the restriction.

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The dialog must be created with `FileDialog` directly and `mode='r'` set, because `askopenfilename` bypasses extension filtering entirely.