Computer Knowledge

GUI and Web Frameworks

1,711 Questions

Graphical user interface and web frameworks involve layout management, directives, and application design across platforms like Android and Angular. These concepts are tested in computer science and IT officer competitive exams. Review these questions to understand UI components and coding standards.

Android layout attributesAngular structural directivesVB.Net web methodsJava Swing componentsSiebel application framework

GUI and Web Frameworks Questions

Multiple choice

Which lifecycle method is called when a React component is first mounted?

  1. componentDidMount()

  2. componentWillMount()

  3. render()

  4. constructor()
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The componentDidMount() lifecycle method is called immediately after a component is mounted (inserted into the DOM). It is commonly used to perform side effects such as fetching data, setting up event listeners, or integrating with third-party libraries.

Multiple choice

What is the purpose of the shouldComponentUpdate() lifecycle method?

  1. To determine if a component should update when its props or state change

  2. To optimize performance by preventing unnecessary re-renders

  3. To handle state updates and data manipulation

  4. To communicate with other components in the application
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The shouldComponentUpdate() lifecycle method is used to determine whether a component should update when its props or state change. It allows you to optimize performance by preventing unnecessary re-renders, which can be especially important for components with complex or computationally expensive rendering logic.

Multiple choice

Which React hook is used to manage state within a functional component?

  1. useState()

  2. useEffect()

  3. useContext()

  4. useReducer()
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The useState() hook is primarily used to manage state within functional components in React. It allows you to define and update state variables, which can be used to store data and information that changes over time.

Multiple choice

How do you pass data from a child component to a parent component in React?

  1. Using props

  2. Using the this.props object

  3. Using the state object

  4. Using event handlers
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In React, data can be passed from a child component to a parent component using event handlers. By defining an event handler in the child component and passing the data as an argument to the parent component's function, you can communicate between the two components.

Multiple choice

What is the purpose of the context API in React?

  1. To provide a way to share data between components without passing props

  2. To manage state within a functional component

  3. To optimize performance by preventing unnecessary re-renders

  4. To communicate with other components in the application
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The context API in React is used to provide a way to share data between components without passing props. This is especially useful for sharing data that needs to be accessed by multiple components at different levels of the component hierarchy.

Multiple choice

Which React hook is used to access the context API?

  1. useContext()

  2. useEffect()

  3. useState()

  4. useReducer()
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The useContext() hook is used to access the context API in React. It allows functional components to access the context object without having to pass it explicitly as a prop.

Multiple choice

What is the purpose of the forwardRef() API in React?

  1. To pass a ref from a parent component to a child component

  2. To manage state within a functional component

  3. To optimize performance by preventing unnecessary re-renders

  4. To communicate with other components in the application
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The forwardRef() API in React is used to pass a ref from a parent component to a child component. This allows the parent component to access the DOM element of the child component, which can be useful for focusing, measuring, or performing other operations on the element.

Multiple choice

What is the purpose of data binding in Angular?

  1. To establish a connection between the component's properties and the DOM elements.

  2. To define the structure of the component's template.

  3. To handle user interactions with the component.

  4. To manage the state of the component.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Data binding in Angular allows you to connect the properties of your component to the DOM elements in your template, enabling the component to dynamically update the content of the DOM based on changes to its properties.

Multiple choice

Which of the following is NOT a type of data binding in Angular?

  1. Interpolation

  2. Property Binding

  3. Event Binding

  4. Structural Binding
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Structural Binding is not a type of data binding in Angular. The three main types of data binding in Angular are Interpolation, Property Binding, and Event Binding.

Multiple choice

What is the purpose of property binding in Angular?

  1. To set the value of a DOM element's property based on a component property.

  2. To listen for events on a DOM element and respond to them.

  3. To conditionally include or exclude DOM elements from the template.

  4. To repeat a block of HTML for a collection of data.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Property binding in Angular allows you to set the value of a DOM element's property based on the value of a component property. This enables you to dynamically update the DOM based on changes to the component's properties.

Multiple choice

What is the syntax for property binding in Angular?

  1. {{ property }}

  2. [(property)]

  3. (property)

  4. [property]
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Property binding in Angular is denoted by square brackets []. It allows you to bind a component property to a DOM element's property, enabling you to dynamically update the DOM based on changes to the component's properties.

Multiple choice

What is the purpose of event binding in Angular?

  1. To set the value of a DOM element's property based on a component property.

  2. To listen for events on a DOM element and respond to them.

  3. To conditionally include or exclude DOM elements from the template.

  4. To repeat a block of HTML for a collection of data.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Event binding in Angular allows you to listen for events on a DOM element and respond to them by executing a method in your component. This enables you to handle user interactions with the DOM.

Multiple choice

What is the syntax for event binding in Angular?

  1. {{ property }}

  2. [(property)]

  3. (property)

  4. [property]
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Event binding in Angular is denoted by parentheses (). It allows you to bind a DOM event to a method in your component, enabling you to handle user interactions with the DOM.

Multiple choice

What is a structural directive in Angular?

  1. A directive that adds or removes DOM elements from the template based on a condition.

  2. A directive that modifies the behavior of a DOM element.

  3. A directive that listens for events on a DOM element.

  4. A directive that binds a component property to a DOM element's property.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Structural directives in Angular are directives that can add, remove, or manipulate DOM elements based on a condition. They are used to conditionally include or exclude DOM elements from the template.

Multiple choice

What is an example of a structural directive in Angular?

  1. ngIf

  2. ngFor

  3. ngSwitch

  4. ngClass
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

ngIf is an example of a structural directive in Angular. It allows you to conditionally include or exclude a DOM element from the template based on a condition.