PCPP1 Graphical User Interface Programming Practice Test 2 — 15 Questions

Question 1

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?

Choose an answer to begin — your selection is scored in the full session.

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)

Answer

treeview.item(item, open=True)

Question 2

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)

Answer

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

Question 3

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.

Answer

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

Answer

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

Question 4

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.

Answer

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 5

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.

Answer

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

Question 6

A Tkinter application displays a list of records in a ttk.Treeview. When a user selects a row, a details panel must update, and some rows must be shown with a different background to indicate an error state. The developer reports that selection events fire twice for a single click and that per-row background colors are ignored. Which explanation and correction is correct?

Accepted Answer

The duplicate event comes from binding both and <>; bind only <> for selection changes. Per-row colors require configuring a tag with a background and applying that tag to the row with the item method.. Treeview emits the virtual event <> whenever the selection changes, so listening to that event alone is sufficient and prevents the duplicate handling that occurs when a raw button binding is also present. Row-level background coloring is not an item option; it is achieved by configuring a tag with a background and applying that tag to the row, which is the supported styling path.

Answer

The duplicate event is normal because <> fires on both press and release; filter one of them. Per-row colors require inserting the row into a separate Treeview with a styled theme.

Answer

The duplicate event comes from binding <> twice; unbind one copy. Per-row colors require setting the row's foreground option through the item method.

Answer

The duplicate event is caused by the Treeview's selectmode being set to "extended"; change it to "browse". Per-row colors require passing a style name to each row's values tuple.

Question 7

You are developing a Tkinter application that uses a ttk.Notebook widget to manage multiple tabs. You need to add a new tab that contains a Frame with several widgets. You also want to associate a specific image icon with the tab. Which two of the following steps are necessary to add a tab with a custom icon to the Notebook? (Choose two.)

Accepted Answer

Create a ttk.Frame as the container for the tab's content.. To add a tab with a custom icon to a ttk.Notebook, you must create a container (usually a Frame) for the tab's content and then use the Notebook's add method with the 'image' option to set the icon. The other options are either alternative methods that are not strictly necessary or incorrect approaches.

Answer

Call the Notebook's tab method to set the 'image' option for the tab.

Answer

Create a ttk.Label to hold the image and set it as the tab's label widget.

Answer

Set the Notebook's 'style' to a custom style that includes the icon.

Question 8

You have a Checkbutton and you need to track its state. What is the recommended way to associate a variable with the Checkbutton?

Accepted Answer

Pass a BooleanVar object to the 'variable' parameter.. A BooleanVar or IntVar should be passed to the 'variable' parameter of the Checkbutton.

Answer

Use the 'onvalue' parameter.

Answer

Use the state attribute directly.

Answer

Use the 'command' parameter to set a global flag.

Question 9

You want to bind a function 'on_click' to a left mouse button click on a Button widget. Which event sequence string is correct?

Accepted Answer

. The event sequence '' corresponds to the primary (left) mouse button.

Answer

<Mouse-1>

Answer

<Left-Click>

Answer

<Click-1>

Question 10

You need to add a label that displays static text in your GUI. Which widget is most appropriate for this purpose?

Accepted Answer

tk.Label(). tk.Label() is the canonical Tkinter widget for displaying static, non-editable text (or images) in a GUI. It supports options like text, font, fg, bg, and anchor, and is designed specifically for read-only display. For multi-line static text, tk.Message() is a variant, but tk.Label() is the general-purpose choice.

Answer

tk.Message()

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tk.Entry()

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tk.Display()

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tk.Text()

Question 11

In a Tkinter grid layout, you want a button to span across two columns. Which parameter should you use?

Accepted Answer

columnspan=2. The columnspan parameter in the grid() method manager allows a widget to occupy multiple columns.

Answer

span_cols=2

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merge=2

Answer

cols=2

Question 12

You have a Tkinter Entry widget and want to retrieve the text currently entered by the user. Which method do you call on the Entry instance?

Accepted Answer

entry.get(). The get() method is used to retrieve the current contents of Entry and Text widgets.

Answer

entry.content()

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entry.text()

Answer

entry.value()

Question 13

You are creating a simple Tkinter application and notice that your window does not appear on the screen after calling the Tk() constructor. Which method must be called to start the event loop?

Accepted Answer

root.mainloop(). The mainloop() method is required to start the Tkinter event loop, which listens for events and updates the display.

Answer

root.show()

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root.render()

Answer

root.run()

Question 14

Which module must be imported to utilize Tkinter in a Python script?

Accepted Answer

import tkinter. Tkinter is Python's standard GUI library, and it is imported with the statement 'import tkinter' (lowercase). This is the correct module name in Python 3; in Python 2 it was 'Tkinter' with a capital T, but Python 3 standardized it to lowercase.

Answer

import gui

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from python import gui

Answer

import tk

Question 15

What is the correct way to specify the title of a Tkinter window?

Accepted Answer

root.title('My App'). Tkinter's Tk and Toplevel widget classes expose the title() method, which is the canonical API for setting the window manager caption. Calling root.title('My App') sets the WM_NAME property on the underlying X11/Win32 window, which the OS window manager renders in the title bar. There is no set_title() method on Tkinter widgets, so option A would raise an AttributeError at runtime.

Answer

root.set_title('My App')

Answer

root.name = 'My App'

Answer

root.set_header('My App')