CS 213 Software Methodology - Android Essentials 2

Flashcards covering key concepts from an Android development lecture, including components, activities, intents, UI elements, and essential files.

What languages can Android apps be written in?

Kotlin, Java, or C++

What ID does the Android OS assign to each app?

A unique Linux user ID

What are the four different types of app components in Android?

Activities, Services, Broadcast receivers, Content providers

Why can apps with the same user ID can also arrange to run in the same Linux process and share the same VM?

To conserve system resources

Which crucial component of an Android app, is a fundamental part of the platform's application model?

The Activity class

Generally, what does one activity implement?

Implement one screen

What is manifest?

To use activities in your app, you must register information about them in the app’s __ and manage activity lifecycles appropriately.

What can good implementation of the lifecycle callbacks help ensure?

Ensuring that your app avoids crashing

What is a task in Android?

A collection of activities users interact with when performing a certain job

What is commonly perfromed in the onCreate() method?

Instantiation of class-scope variables

The previous activity is stopped, but the system preserves the activity in a stack (the "back stack")

When a new activity starts, what happen to the previous one?

What State does the activity enter after the onCreate() method finishes execution?

The activity enters the Started state, and the system calls the onStart() and onResume() methods in quick succession.

What happens when the activity enters the Resumed state?

The state in which the app interacts with the user

What is the first indication the system uses when calling the onPause() method?

That the user is leaving your activity

In the onStop() method, what should the app do?

The app should release or adjust resources that are not needed while the app is not visible to the user.

Does a service perform long-running operations in the background provide a user interface?

It does not provide a user interface

What are broadcast receivers used for?

Send or receive broadcast messages from the Android system and other Android apps

What is the asynchronous message that activates activities, services, and broadcast receivers?

An intent

What are the two types of Intents?

Explicit and Implicit

What do explicit intents specify?

specifies which application will satisfy the intent, by supplying either the target app's package name or a fully-qualified component class name

When does the system start a component based on the intent?

The intent matches an intent filter

What is the 'Action' when building an Intent object?

A string that specifies the generic action to perform

What is a Context in Android?

An Interface to global information about an application environment

What is the name of the app's manifest file?

AndroidManifest.xml

What is the primary task of the manifest file?

To inform the system about the app's components

What type of file are animations, menus, styles, colors, and the layout of activity user interfaces defined with?

XML files

What is a drawable resource?

A general concept for a graphic that can be drawn to the screen

What does a layout define?

The structure of a user interface in your app

What are the two ways to declare a layout?

In XML or at runtime

What does every element of the screen is consist of?

A View

ConstraintLayout is similar to what?

RelativeLayout

When is Toast message triggered?

Clicking Send on an email triggers a 'Sending message…' toast

What is Toast?

A small popup that provides simple feedback about an operation

Which window in Android Studio displays system messages and messages added to your app with the Log class?

The Logcat window

Which Log method would you use to log an error?

Log.e()

What is a Bundle in Android?

A collection of data, stored as key/value pairs

What does AVD stand for?

An Android Virtual Device

What is an APK?

An Android application package