Advanced Programming and Flutter Assessment

The final keyword in Dart makes a variable immutable at runtime. It can be assigned a value only once, but this assignment can occur at any time during execution.

The const keyword in Dart creates a compile-time constant. This means the value is fixed at the time the code is compiled and cannot be changed later. Compile-time constants are often used for performance optimization as they can be resolved during the compilation stage.

The abstract keyword in Dart is used to define an abstract class. Abstract classes cannot be instantiated directly, but they can be extended by other classes. They serve as blueprints for concrete classes, providing a structure for shared functionality.

The factory keyword in Dart is used to define a factory constructor. Factory constructors allow you to control how objects are created, potentially returning an existing object, a new object, or something entirely different.

Dart's inheritance model features single inheritance, meaning a class can inherit from only one parent class. This ensures a clear and organized class hierarchy, avoiding potential conflicts that might arise from multiple inheritance.

The super keyword in Dart is used to access members (fields and methods) of the parent class from within a child class. This allows you to extend and reuse functionality inherited from the parent, adding or modifying behavior as needed.

Dart's type system is based on static typing, meaning that types are checked at compile time. This enables early detection of errors and improves the overall code quality and reliability. During the compilation process, the compiler verifies that all variables and function parameters have consistent types, preventing potential runtime type mismatches and ensuring proper type safety.

In Dart, null safety is a feature where variables cannot be null unless specifically marked as nullable. This helps prevent runtime errors caused by unexpected null values and improves code reliability. With null safety, you can be confident that variables will always have a valid value, making your code safer and easier to reason about.

An optional parameter in Dart allows you to define a function parameter that can be omitted during function calls. If the parameter is not provided, it will assume a default value. This provides flexibility in how you call your functions, making your code more adaptable to various scenarios.

In Dart, the Future class represents an asynchronous computation that will eventually produce a value. These futures are very useful in situations where a result may not be immediately available, such as a network request or complex calculation. You can use them to handle the eventual outcome of these operations without blocking the current thread.

A stream in Dart allows processing multiple sequential values, like a continuous flow of data.

The on keyword in error handling lets you specify the type of error you want to handle, while catch handles any error regardless of type.

Dart uses the ? operator after a variable's type to indicate that the variable can be null. For example, String? name means the name variable can hold a string or can be null.

When you use late on a variable but never initialize it, Dart throws a runtime error when you try to access it. It is an error that occurs during program execution, not compilation.

To create an immutable list in Dart, you should use the const keyword. This ensures that the list cannot be modified after it's created.

A Set in Dart is used to store unique elements. Duplicates are automatically discarded. This is in contrast to a List, which can hold duplicate elements.

In Flutter, the build method is the core of a widget. It's responsible for defining the structure of the widget, its UI elements, and how it interacts with data.

The ListView widget is used to create a scrollable list of widgets in Flutter. Users can scroll through the list to view all items.

A StatefulWidget manages changes to the user interface (UI) state based on user interactions or other events. In contrast, a StatelessWidget remains static and does not change its appearance.

Data can be passed between screens using constructors, global variables, and Navigator arguments. Using constructors is ideal for passing data to a new screen, global variables enable data access across the app, and Navigator arguments help transfer information during navigation.

This method is used in StatefulWidget to signal a state change, causing the widget tree to be rebuilt, thus updating the UI to reflect the new state.

The GestureDetector widget enables you to capture and respond to user gestures like taps, drags, and long presses on UI elements. This allows you to handle user interactions effectively.

You can make API requests in Flutter using the http package, which is a part of the Dart programming language.

The Scaffold widget provides a basic structure for app layouts in Flutter. It offers a standard framework for common UI components, such as app bars, drawers, and floating action buttons (FABs).

You can add padding to widgets using the Padding widget in Flutter. It adds space around a widget, creating visual spacing and improving readability.

The FutureBuilder widget enables you to manage asynchronous data and update the UI accordingly. It helps to display loading indicators while waiting for data and seamlessly update the UI once the data is available.