Android Basics

Question 1

What are the 3 basic types of mobile apps

Answer 1

Native
Web apps
Hybrid

Question 2

What is a Web app

Answer 2

Responsive version of a website that works on any mobile device or OS
Delivered via mobile browser

Question 3

What is a hybrid app

Answer 3

Combination of web app and native app
Web app that is wrapped in a native app so it can be downloaded

Question 4

What are native apps

Answer 4

Built for the Mobile device OS
require installation
written in Android or swift

Question 5

What are some benefits of Native apps

Answer 5

• Provide access to all the standard tools and features and are compatible with native features such as sensors, hand gestures, accelerometer
  -Performance

Question 6

What are Web apps usually built with

Answer 6

HTML5, CSS, JavaScript

Question 7

What is a PWA

Answer 7

Progressive Web app

• native web app running insides a browser
• Web app that functions like a native mobile app
• has a homescreen icon, responsive design, offline functionality
• Get automatic updates
• Offer good performance
• provide users with a more app-like experience on the web

Question 8

What is the Dalvik VM

Answer 8

A pioneering virtual machine that paved the way for Android’s success. It allowed applications to run on the android device
- superseded by Android Runtime (ART), its legacy remains in the foundation of the Android ecosystem.

Question 9

What is Android jetpack

Answer 9

Suite of software components, libraries, tools, and guidance provided by Google to help developers build robust, high-quality Android applications.

Benefits - reduces boilerplate code, ensures consistent apps

Includes AndroidX which is used for backwards compatibility

Question 10

What is AndroidX

Answer 10

Provides backwards compatibility across Android releases

Question 11

How do Android apps work

Answer 11

Device launches app
app creates activity object
Activity tells Android what layout to display
User interacts with the layout
Activity responds to the interaction by running application code
Activity updates the display

Question 12

What are view groups

Answer 12

Invisible container for views

Question 13

What are common android layouts

Answer 13

Linear
Relative (Constraint layout is preferred)
Web view to display web pages
Adaptor layouts: list view, grid view, recycler view
Constraint layout

Question 14

Constraint layout

Answer 14

default layout
has a flat hierarchy
Needs at least one horizontal and one vertical constraint for the view

Question 15

What are the main files in android

Answer 15

Manifest
Gradle scripts
java
res

Question 16

What are the gradle scripts

Answer 16

build.gradle project
build.gradle module
settings. gradle

Question 17

What are the common res files

Answer 17

drawables
layout files
menu
values (strings)

Question 18

What does the Android manifest do

Answer 18

declares components (activities, services)
defines permissions (camera, location, storage)
set config (min level supported)
app metadata (helps user understand app)

Question 19

What does the settings.gradle do

Answer 19

defines the project hierarchy
Defines plugins remote repositories like Maven

Question 20

What does MainActivity.java do

Answer 20

• defines how the app will behave and interact with the user
• Starts the activity and loads the layout set by setContentView() method

Question 21

What are the different stages in the activity lifecycle

Answer 21

onCreate()
onStart()
on Resume()
ACTIVITY RUNNING
on Pause()&raquo_space; go to onResume
on Stop()&raquo_space; go to onCreate from here if other apps need the memory, or go to onRestart()
on Destroy
ACTIVITY SHUT DOWN

Question 22

What is AppCompatActivity

Answer 22

Base class for activities and uses an app bar

Question 23

What is the Bundle savedInstanceState

Answer 23

Previously frozen state if there was one

Question 24

What does the setContentView method do

Answer 24

loads the activity_main.xml
sets the activity content from a layout resource that will be inflated, adding all the top level view to the activity

Question 25

What is an Android Emulator What is an AVD

Answer 25

Simulates an android device and displays the application on the computer AVD - Android Virtual Device

Question 26

What is Logcat

Answer 26

Provides information about the logs

Question 27

What is an APK

Answer 27

Android Application Package

Question 28

What is an event listener

Answer 28

Captures user interactions with the UI interface in the View class Contains a single callback method

Question 29

What is View binding

Answer 29

Helps you to interact more easily with views

Question 30

What are the advantages of View binding over FindViewByID

Answer 30

Type safety Null pointer safety

Question 31

What is Android Context

Answer 31

Abstract class allows access to information about resources and classes

Question 32

What is an intent

Answer 32

- Can be used to start an activity - Can be used to start a service - Can be used to start a broadcast - Can be used to pass data between activities

Question 33

What parameters does an intent constructor need

Answer 33

Context and a class

Question 34

How can you pass data between multiple activites

Answer 34

Use objects of: Intent Bundle

Question 35

How can you use an intent to pass primitive data

Answer 35

using putExtra which requires a keyname and its value

Question 36

How do you use a Bundle to pass primitive data

Answer 36

Create a bundle to send a set of data items with intent Add all the data items into one bundle object

Question 37

Parcelable class

Answer 37

Package an object's data and transfer it between activities or other components within your app in a serialized format. To make your class Parcelable, you need to: Implement the Parcelable interface. Override the writeToParcel(Parcel dest, int flags) method to write your object's state to the parcel. Implement a static CREATOR field that provides a method to create an object from a parcel.

Question 38

What is a spinner

Answer 38

- displays a set of values that the user can click on - show which item is selected - when touched shows a dropdown with all other available items

Question 39

How is a spinner populated

Answer 39

with a SpinnerAdaptor such as an Array Adaptor

Question 40

How do you add items to a spinner in 4 steps

Answer 40

- Declare a list to hold the items to display - Instantiate an ArrayAdapter - To add items first add them to the adapter - Notify the Adapter of the change so it refreshes itself

Question 41

How is view Binding set up

Answer 41

Gradle change: set view Binding to be true Class level: - import view binding - private ActivityMainBinding binding (set a variable with the name of the resource file as the binding object) - binding=ActivityMainBinding,inflate(getLayoutInflator()) View view = binding.getRoot()