Project Components

src – your source code

gen – auto-generated code (usually just R.java)

libs - Included  libraries

Resources

Drawables (like .png images)

Layouts

Values (like strings)

Manifest file

SRC(Contains Source Code)

In Android Development the src folder is where all you put your main Java code

EX. MainActivity.Java

XML

Used to define some of the resources

Layouts (UI)

Strings

Manifest file

Shouldn’t usually have to edit it directly, Eclipse can do that for you

Preferred way of creating UIs

Separates the description of the layout from any actual code that controls it

Can easily take a UI from one platform to another

R Class

Auto-generated: you shouldn’t edit it

Contains IDs of the project resources

Enforces good software engineering

Use findViewById and Resources object to get access to the resources

Ex. Button b = (Button)findViewById(R.id.button1)

Ex. getResources().getString(R.string.hello));

 Layout

Eclipse has a great UI creator

Generates the XML for you

Composed of View objects

Can be specified for portrait and landscape mode

Use same file name, so can make completely different UIs for the orientations without modifying any code.

Strings

 In res/values

strings.xml

Application wide available strings

Promotes good software engineering

UI components made in the UI editor should have text defined in strings.xml

Strings are just one kind of ‘Value’ there are many others

Menifest File

Contains characteristics about your application

When have more than one Activity in app, NEED to specify it in manifest file

Go to graphical view of the manifest file

Add an Activity in the bottom right

Browse for the name of the activity

Need to specify Services and other components too

Also important to define permissions and external libraries, like Google Maps API

Drawables

A Drawable resource is a general concept for a graphic which can be drawn. The simplest case is a graphical file, which would be represented in Android via a BitmapDrawable class. Bitmaps are typically stored in one of theres/drawable folders. The Android project creation wizard creates several of these folders by default, you can provide different sized files for different resolutions of Android devices. If you only provide one file for all sizes the Android system will scale the resource.

In additional to graphical files, Android supports XML drawables and 9-patch graphics. XML drawables are used to describe shapes (color, border, gradient), State and Transitions and more.

9-patch graphics are used to define which part of a graphic should be stretched if the View which uses this graphic is larger than the graphic.

Libs

The /lib folder is used to import library files in project that executables make use of and also you can import third party library files .