androids

Question 1

what is the linux kernel used for

Answer 1

core OS services, multi threading, memory management

Question 2

what libary does android runtime use

Answer 2

Java libary

Question 3

How do android apps run their process

Answer 3

they use the dalvik virtual machine that executes files in the dalvik executable (.dex). Optimised for low memory footprint

Question 4

Library use:C/C++

Answer 4

exposed through android application framework

Question 5

Library use:System C

Answer 5

tuned for imbedded linux based devices

Question 6

Library use:LibWebCore

Answer 6

Web browser engine which powers android browser and embedded web view

Question 7

Library use:3d libraries

Answer 7

hardware 3d acceleration

Question 8

What is application framework and what is it used for

Answer 8

Provides access to device hardware, location information, background services(alarms etc). Designed for component reuse and interplay between apps

Question 9

Views?

Answer 9

used to build apps, eg lists grids text boxes, buttons

Question 10

content providers

Answer 10

enable apps to interchange info between each other

Question 11

resource manager

Answer 11

provides access to non code resources such as localised strings , images and layout files

Question 12

activity manager

Answer 12

manages app lifecycle and navigation

Question 13

how are applications bundled

Answer 13

in .apk files which are used to distribute and install apps on mobile devices

Question 14

Activities

Answer 14

Represents a single screen with user interfance, in short it performs activities on the screen

Question 15

what are the states of an activity after onCreate()

Answer 15

onStart() and then onResume()

Question 16

what happens after a new activity comes after an activity is running

Answer 16

the original activity goes into onPause() state and then goes back to onResume() or onStop

Question 17

what can an activity do in the onStop() state

Answer 17

it can be killed and go to onCreate() if apps need memory, it can go to onRestart() and then onStart() if user navigates to that activity or can be destroyed through the onDestroy() state

Question 18

Services:

Answer 18

run in the background and support long-running operations like downloading media or remote processes like email client

Question 19

broadcast receivers

Answer 19

listen for and respond to events, like messaging app

Question 20

content providers

Answer 20

supplies data from one application to others on request

Question 21

True or false: manifests, java, res and gradle scripts are part of an app structure

Answer 21

True

Question 22

what does the Res contain

Answer 22

the XML file which contains the app layout

Question 23

what does the manifests contain

Answer 23

the manifest file, vital for declaring the app’s components, permissions and other core configs

Question 24

what is an intent

Answer 24

description of operation to be performed. It is used to request an action from another app component

Question 24

whats the difference between an explicit and implicit intent

Answer 24

explicit is an activity in your own application, implicit is when you ask the system to find a suitable activity

Question 24

what 3 parameters do android toasts take

Answer 24

first method needs a Context object which is obtained by calling getApplicationContext(). second is the text in the toast, third is the length the toast should be displayed