Git Branch vs Tag: Differences and Uses Quiz and Flashcards

Questions and Answers

What is the difference between a Fragment and an Activity?

A Fragment is a reusable component of an activity's user interface, while an Activity represents a single screen with a user interface.

When should you use a Fragment rather than an Activity?

Fragments should be used when you want to create a modular and reusable component that can be added or removed from an activity dynamically.

Explain the relationship between a Fragment and an Activity.

A Fragment is always hosted by an Activity and cannot exist independently. It is tightly coupled with the Activity that hosts it.

How do broadcasts and intents work to pass messages around an app?

<p>Broadcasts are sent using Intents to deliver messages or events from one component to another within an app. Components can register to receive these broadcasts and handle them accordingly.</p> Signup and view all the answers

Why should you avoid running non-UI code on the main thread?

<p>Running non-UI code on the main thread can cause the user interface to freeze, resulting in poor user experience. It is recommended to offload such tasks to background threads or use asynchronous programming.</p> Signup and view all the answers

Study Notes

Fragments and Activities

A Fragment is a reusable piece of user interface that can be used in multiple activities, whereas an Activity is a single, focused thing that the user can do.
Fragments are not complete without being hosted by an Activity, which manages the Fragment's lifecycle.

When to Use a Fragment

Use a Fragment when you want to reuse a UI component in multiple activities, or when you want to dynamically change the layout of an Activity.
Fragments are useful for tablet-sized screens, where you can display multiple Fragments at once, and for creating a responsive UI.

Fragment-Activity Relationship

An Activity can host multiple Fragments, and a Fragment can be hosted by multiple Activities.
The Activity manages the Fragment's lifecycle, and communicates with the Fragment using a FragmentManager.

Broadcasts and Intents

Broadcasts and intents are used to pass messages between different components of an app, such as between Activities, Services, and BroadcastReceivers.
An intent is a message object that specifies an action to be performed, and optionally includes data and a target component to receive the intent.
A broadcast is a message that is sent to multiple components, and any component that has registered to receive the broadcast can respond to it.

Main Thread and Non-UI Code

The main thread is responsible for handling UI-related tasks, and should not be blocked by long-running operations.
Running non-UI code on the main thread can cause the app to become unresponsive, and may lead to an Application Not Responding (ANR) error.
Non-UI code should be run on a separate thread or using an AsyncTask to avoid blocking the main thread.