Mostly Android

Question 1

What are some of the things stored in the android manifest?

Answer 1

• Declares Package name
• Activities
• app name
• launcher icon
• permissions for the app

Question 2

WHere are these defined: UI and Functionality

Answer 2

XML and Java Code (Activities)

Question 3

Where in java code do you inflate the XML layout

Answer 3

In the onCreate method

Question 4

With activity lifecycles, what are the four states?

Answer 4

Active, Visible, Hidden and Destroyed

Question 5

in the activity stack, what’s the order? (Visible, Destroyed, Active and Hidden)

Answer 5

From top to bottom: Active-Visible-Hidden-Destroyed

Question 6

When is the R class generated

Answer 6

When the application is compiled

Question 7

What does the R class contain?

Answer 7

Contains access for all the resources in the res directory.

Question 8

R.drawable.icon what is the datatype of this command?

Answer 8

A static Integer

Question 9

How would you access Views? ie TextViews in XML

Answer 9

(TextView) findByView(R.id.textviewidname)

Question 10

Can you find viewGroups the same way you find Views in java?

Answer 10

Yes, Viewgroups are just special types of View

Question 11

how would you set up a button event listener with this code:
Button b =
(Button)findViewById(R.id.button1);

Answer 11

b.setOnClickListener(new View.OnClickListener() {
public void onClick(View v){
// do something
}
});

Question 12

How would you define onclick method in XML then access it from java

Answer 12

android:onClick=”onClick”
then java:

public void onclickSubmit(View v) {
// some code
}

Question 13

How would you launch another activity from any given activity

Answer 13

With intents

Question 14

launching an activity requires an explicit or implicit intent?

Answer 14

Explicit

Question 15

When passing through data to a new intent, which method would you use?

Answer 15

intent.putExtra(“key”, value)

Question 16

when recieving an intent from another activity, which method do you use, and what variable would you pass it?

Answer 16

intent.getStringExtra(“variable_name”);

Question 17

What is an Implicit Intent? and an example

Answer 17

An implicit intent declares a general action to perform, which allows another app to handle the action. example: if you wanted to share text or images through social media, you would use an implicit intent to notify other apps that you have content to share

Question 18

Implicit intents contain which information

Answer 18

Action - to perform
Data - URI or MIME type
Category - which type of component that can handle the intent
Extras - any extra info

Question 19

What are the two types of context? Why would you use one over the other?

Answer 19

application context and activity context. Only use application context if it needs to live beyond your activity

Question 20

what ways can you get access to context

Answer 20

this, getApplicationContext() (in an activity)

Question 21

Explain the usefulness of the singleton pattern

Answer 21

if exactly one object is needed, as the singleton pattern restricts instantiation of a class to one instance

Question 22

Features of a singleton class

Answer 22

Private static Singleton;
Private constructor;
public static method that returns instance of itself

Question 23

Simple explaination of a Adapter pattern

Answer 23

Allows incompatible classes to work together by converting the interface of one class to match the other.

Question 24

How do Array Adapters work with List Views and a string array?

Answer 24

ArrayAdapters create a view for each array item, by calling toString() on each time and placing the result in a textView

Question 25

TextView, EditText… inherit from which class?

Answer 25

View, which inherits from Object

Question 26

Linear Layout, RelativeLayout… inherit from which class?

Answer 26

ViewGroup Class

Question 27

Can a View, contain a ViewGroup?

Answer 27

No, an ViewGroup is a special type of View

Question 28

You can draw to canvas, and to…?

Answer 28

A view

Question 29

You should draw to a view when?

Answer 29

Your graphics don’t need to change dynamically

Question 30

You should draw to a canvas when?

Answer 30

Your app needs to re-draw itself, such as in a game

Question 31

What is lean back mode used for. how to bring back the nav bar?

Answer 31

when users wont be interacting with the screen, such as when watching a movie. Navbar is brought back with a tap

Question 32

what is the immersive mode used for? how to bring back the system bars?

Answer 32

When users will be heavily interacting with the screen, bring back system bars by swiping in from edge

Question 33

What is immersive sticky mode for?

Answer 33

intended for games that require a lot of swiping. navbar appears transparent if swiping in from edge, but will disapear if the screen is tapped, or after a few seconds

Question 34

How would you keep track of multiple touches on the screen at once

Answer 34

By usiung a forloop that goes through the switch case, covering Event.down event.move and event.up
for every “pointer” on screnn

Question 35

When implimenting accelorometer, which methods do you need to register/initialize/unregister the listener

Answer 35

onCreate, onPause and onResume

Question 36

to listen for gestures, you will need to initialize what class>

Answer 36

The GestureDector class, then use gestureDetector.onTouchEvent(MotionEvent object) under onTouchEvent Overriden method

Question 37

by using GestureDetector,onGestureListener, you have to then override all the gesture types, what should you do if you only want to override one type of gesture?`

Answer 37

by Extending GestureDetector.SimpleOnGestureListener, then using that class 
gestureDector = new GestureDetector(context, new MySimpleGestureListener()) where MySimpleGestureListener() is the class you just created which extends SimpleOnGestureListener.

Question 38

what is an apk?

Answer 38

apk is the file format used by android for distribution