Android

volley

HTTP lib that makes networking for android apps easier and faster

viewmodel

a class that is responsible for preparing and managing the data for an activity or fragment. manages data for the UI

thread

a component that does some type of execution within a program

collection

a group of individual objects represented as a single unit

rxjava

a library for composing asynchronous and event-based programs using observable sequences for the JVM

fragments

a piece of an application's user interface or behavior that can be placed in an Activity which enable a more modular activity design. It will not be wrong if we say a fragment is a kind of subactivity.

method-overloading

a single method that performs different functions depending on the context in which its called

inheritance

allows a new class to adopt the properties of another

content providers

allows applications to publish and share data with other applications

notifications manager

allows apps to send and display alerts/notifications to the user

view system

an extensible set of views used to create application user interfaces

api level

an integer value that uniquely identifies the framework API revision offered by a version of the android platform

service

application component representing either an app's desire to perform a longer-running operation while not interacting with the user or to supply functionality for other apps to use.

espresso

automatically synchronizes your test actions with the UI of your app. -ensures that your activity starts before your tests run

view

basic building block for UI components

view object

basic building block for ui

finally

block that contains all the crucial statements that must be executed whether an exception occurs or not

gradle

build system that is used for android to automate building, testing and development

application components

building blocks of android apps. -components are loosely coupled by the application's manifest file that describes each component and how they interact

intents

carries information that the android system uses to determine which component to start

method-overriding

child class can use oop polymorphism concept to override method of its parent class

lifecycle

class that holds information about the lifecycle state of a component (e.g. activity/fragment) and allows others to observe this state

bundle

collection of data stored as a key/value pairs, to pass info from one activity to another.

modules

collection of source files and build settings that allow you to divide your project into discrete units

val

constant variables and cannot be assigned multiple times, can only be initialized a single time. -immutable variable in kotlin

activity manager

controls all aspects of the application and activity stack

livedata

data holder that can be observed within a given lifecycle

async task

designed to be a helper class around thread and handler and does not constitute a generic threading framework. - computation that runs on a background thread and whose result is published on the UI thread.

activities

dictate the ui and handle user interaction to the device screen

relative layout

displays child views in a relative position

grid layout

displays items in a two-dimensional, scrollable grid

list layout

displays list of scrollable items

?:

elvis operator, evaluates the left expression and will return it if its not null, else will evaluate the right side of the expression

absolute layout

enables you to specify the exact location of its children

extension functions

extends the functionality of classes without having to touch their code

navigation

framework for navigating between 'destinations' within an android app. -provides a consistent api whether destinations are implemented as fragments, activities or other components

var

general variable and can be assigned multiple times. -mutable variable in kotlin

table layout

groups views into rows and columns

services

handle background processing associated with the application

broadcast receivers

handle communication between android operating system and applications

content providers

handle data and database management issues

okhttp

how we exchange data and media -makes stuff load faster and saves bandwidth

coil

image loading library backed by kotlin coroutines

glide

image loading library focused on smooth scrolling

picasso

image loading library with minimal memory use, also includes automatic memory and disk caching

event listeners

interfaces in the view class that contains a single callback method. -the method will be called when the view to which the listener has been registered is triggered by user interaction with the item in the ui

gson

java library that can be used to convert java objects into their JSON representation (vice-versa)

encapsulation

keeping details (like data and procedures) together in one part of a program so that programmers working on other parts of the program don't need to know about them.

intent extras

key/value pairs in a bundle

linear layout

layout that aligns all children in a single direction, vertical or horizontal

work manager

makes it easy to schedule deferable, asynchronous tasks that are expected to run even if the app exits or device restarts

mockito

mocking framework used for testing

mvvm

model, view, view model.

moshi

modern JSON serialization tool, allowing you to put into annotations for a more fine grained/contextual deserialization.

implicit intent

one in which you do not have the name of the target component, but have a general action to perform

singleton

only a single instance of a class is required to control the action throughout the execution

frame layout

placeholder on screen that you can use to display a single view

event listeners registration

process by which an event handler gets registered with an event listener so that the handler is called when the event listener fires the event

oop

programming paradigm that is based on the concept of "objects", which contain data, in the form of fields and code

resource manager

provides access to non-coded resources such as strings, color settings and user-interface layouts

infix notation

provides more readability to a function similar to other operators like in , is , as

inline

requests the cpu to not allocate any memory for the function and simply copy the body of that function at the calling place

?.

safe calls, or another way of using a nullable property.

data class

simple way to represent, encapsulate and move information around

access modifier

specify the scope of a data member, method, constructor or a class

lateinit

stands for late-initialization and is used when you are sure a variable wont be null or empty and will be initialized before you use it.

view group

subclass of view, provides invisible container that hold other views or other view groups and define layout properties

jetpack

suite of libraries, tools and guidance to help write high quality apps easier

databinding

support library that allows you to bind UI components in your layouts to data sources in your app using declarative format rather than programmatically

junit

testing framework for java

roboelectric

tests that run inside a sandbox, which allows the android environment to be precisely configured to the desired conditions for each test

main thread

the thread that begins running immediately as soon as the program starts up

try/catch

try: allows you to define a block of code to be tested for errors while being executed. catch: allows you to define a block of code to be executed, if an error occurs in the try block

dalvik virtual machine

type of virtual machine specifically designed for android. -allows every android app to run on its own process, with its own instance on the dvm.

retrofit

type-safe HTTP client for android and java that makes it easy to consume JSON or XML data which is parsed into plain old java objects

!!

used explicitly to tell the compiler that the property it is not null, if it is null, throw a null pointer exception

coroutines

used predefined thread pools and smart scheduling. -lightweight threads

events

useful way to collect data about a users interaction with interactive components of applications

polymorphism

using a reference to a parent class to affect an object in the child class

lazy

value gets computed only upon first access

ten

version 10

lollipop

version 5

marshmallow

version 6

nougat

version 7

oreo

version 8

pie

version 9

event handlers

when an event happens and we have registered an event listener for the event, event listener calls event handlers, which is the method that actually handles the event.

explicit intent

you know the target of that intent. already know the fully qualified class name of that specific activity