Java II - Test 2 (JavaFX) Flashcards

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Questions and Answers

What is the primary purpose of a control that displays text?

Label

What type of control appears as a rectangular region that can accept keyboard input?

TextField

What typically occurs when a user clicks a button?

An action takes place

In memory, how are the GUI objects in a scene organized?

Tree Signup and view all the answers

What is the term for the parent of all other nodes in a scene?

Root node Signup and view all the answers

What type of node can have other nodes as children?

Branch node Signup and view all the answers

What type of node cannot have other nodes as children?

Leaf node Signup and view all the answers

All JavaFX applications must extend the __________ class.

Application Signup and view all the answers

What container arranges its contents in a single, vertical row?

VBox Signup and view all the answers

What class is used to load an image file into memory?

Image Signup and view all the answers

What class is used to display an image?

ImageView Signup and view all the answers

What method does the EventHandler interface specify?

Handle Signup and view all the answers

The BorderPane layout container has five regions known as which of the following?

Center Signup and view all the answers

What type of object does a layout container's getChildren() method return?

ObservableList Signup and view all the answers

The Stage class is in the JavaFX package.

False Signup and view all the answers

The HBox container makes all of the nodes it contains the same height.

False Signup and view all the answers

You can nest a layout container inside of another layout container.

True Signup and view all the answers

Only one object at a time may be placed into a BorderPane region.

True Signup and view all the answers

What is an event-driven program?

In a Java GUI app, a user's interaction with a component is called an event. Signup and view all the answers

What is the purpose of the Application class's launch method?

It creates a Stage object that will be the app's window. Signup and view all the answers

What is the purpose of the Application class's abstract start method?

Entry point for the application Signup and view all the answers

What purpose do layout containers serve?

Helps organize parts of the application into separate areas. Signup and view all the answers

What package are the Label, Button, and TextField classes in?

javafx.scene.control Signup and view all the answers

What two classes do you use to display an image?

Image and ImageView Signup and view all the answers

What is an image's aspect ratio? How do you make sure it is preserved when you resize an image?

Aspect ratio = ratio of image's width-to-height, preserved by using setPreserveRatio method and setting it to true. Signup and view all the answers

Which layout container arranges controls in a horizontal row? Which layout container arranges controls in a vertical row? Which layout container arranges controls in rows and columns?

VBox Signup and view all the answers

How do you retrieve the text that the user has entered into a TextField control?

Use the getText() method to return the value in the TextField control. Signup and view all the answers

Describe 3 different techniques for writing event handlers.

<ol> <li>Inner class implementing EventHandler 2) Anonymous inner class 3) Lambda expression.</li> </ol> Signup and view all the answers

Which layout container divides a container into regions known as top, bottom, left, center, and right?

BorderPane Signup and view all the answers

When a selector name starts with a period in a JavaFX CSS style definition, it means the selector corresponds to what?

Specific types of JavaFX nodes Signup and view all the answers

Which of these is written in the correct syntax for a CSS style definition?

.label {-fx-font-size: 20pt;} Signup and view all the answers

Study Notes

JavaFX Controls and Structures

A Label is designed primarily for displaying text in JavaFX applications.
TextField allows user keyboard input within a rectangular area.
A Button triggers an action when clicked.
JavaFX GUI objects are structured in memory as nodes within a Tree.
Each scene can contain only one root node, which is the parent of all other nodes.
Branch nodes can have child nodes, while leaf nodes cannot.
Every JavaFX application must extend the Application class.

Layout Containers

A VBox container organizes its contents in a vertical row.
The Image class loads an image file, while ImageView displays the image.
The EventHandler interface includes a method called handle for handling events.
The BorderPane layout has five regions: Top, Bottom, Left, Right, and Center.
The getChildren() method of layout containers returns an ObservableList.

True or False Statements

The statement about the Stage class being in the JavaFX package is False.
False: The HBox container does not make all contained nodes the same height.
True: Nested layout containers can exist within one another.
True: Only one object can be placed into a BorderPane region at a time.

Event Handling and Application Lifecycle

An event-driven program responds to user interactions, called EVENTS, with specific actions.
The launch method of the Application class creates a Stage object, initializing the application window.
The start method in the Application class serves as the application entry point.

Layout Containers and Their Purpose

Layout containers are essential for organizing application parts into distinct areas.
Classes like Label, Button, and TextField belong to the package javafx.scene.control.
Image and ImageView are the two classes used to display images.

Image Handling

The aspect ratio of an image refers to the ratio of its width to height, preserved by setting setPreserveRatio(true) when resizing.

Various Layouts

HBox arranges controls in a horizontal row.
VBox arranges controls in a vertical row.
GridPane organizes controls in both rows and columns.

User Interaction

The getText() method retrieves user-entered text from a TextField control.
Three techniques for writing event handlers include:
- Defining an inner class implementing EventHandler.
- Using an anonymous inner class for event handling.
- Employing a lambda expression for creating a lightweight event handler.

CSS in JavaFX

The BorderPane divides its layout into top, bottom, left, center, and right regions.
In JavaFX CSS, a selector starting with a period indicates it corresponds to specific types of nodes.
A correct CSS style syntax example is: .label {-fx-font-size: 20pt;}.

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Description

These flashcards are designed to help you review key concepts in JavaFX. Each card presents a word related to GUI (Graphical User Interface) controls and their definitions. Perfect for students preparing for a Java II test focused on JavaFX.