This document introduces Android app development, covering necessary prerequisites such as basic Java concepts and the Android SDK. It provides an overview of the Android platform's history, its market prevalence, and key components of an Android app including activities, manifest files, and resource management. It also emphasizes the use of Android Studio for development and outlines the structure and important aspects of building an Android application.

1. Android App Development
Lesson 1 - Introduction & App Structure

2. Prerequisities
These concepts should all be (VERY?!) familiar :
- Arrays of basic objects and types
- Use and characteristics of ArrayList
- Polymorphism.
- Overriding of methods (e.g. toString())
- Wrapper Classes - Integer, String, Double etc.

3. Android - Why ?
● Android (from Google) will be our platform of choice.
● Approaching 1 BILLION Android enabled devices
currently in the world (September 2014)
● Currently has 51% of the world’s smartphone market
share
● The types of devices (cars, fridges etc etc) are growing
all the time.

4. Android - History
● Originally started in 2005 and bought by Google in 2007.
● Google then started the OHA (Open Handset Alliance) with
the idea of standardizing mobile software platform across
vendors (Samsung, HTC, Motorola etc etc)
● Currently on version 4.4 (nickname ‘Kit Kat’), previous
4.1, 4.2 & 4.3 were nicknamed ‘Jelly Bean’
● Alphabetically ordered sweet treats!

5. The Basics
● We’ll be using Android as our platform of choice.
● Android apps are written in Java. So we need basic
Java installed :)! For this course we’ll use Java 8
(latest)
● We also need Android SDK (extra on top of Java)
● We’ll be using Android Studio as our development tool
of choice. Can also use Eclipse ADT (can be moved to
Android Studio later)

6. Logic
Data
Persistence
VIEW
CONTROLLER
MODEL
DATABASE / FILE
Graphical User
Interface (GUI)
Persistence
Common Design
Pattern

7. Development Environment
Android Studio
(User interface for developing Java Application)
https://developer.android.com/sdk/installing/studio.html
Java 8
(Normal Java)
http://www.oracle.com/technetwo
rk/java/javase/downloads/jdk8-
downloads-2133151.html
Android SDK
● Android Java Classes
● SDK Manager
● AVD Manager (for creating emulators)

8. Using Android Studio
● We could use Eclipse but it’s no longer in active
development.
● Android Studio is what Google are moving towards.
Currently at release candidaate level.
● When we create an App project in Android Studio or
Eclipse we see alot of stuff that “just gets created”.
So what are the basic key parts ?

9. ...
Java Code
Manifest File
Resources (e.g.
Images)

10. Activites
● The basic building block of an app is an Activity.
● An Activity Java class that we write will ultimately
extend from android.app.Activity
● You can think of an Activity as a self-contained
“screen” of your app.
● Each Activity also has a corresponding layout file
(written in XML) - More later.

11. Resources
The very basic types of
resources you would
have would be :
● Images (different resolutions)
● Layout files for each Activity
(these are XML files)
● Strings, Styles and
Dimensions of components.

12. Activity Layouts
● Each Activity Java class has a corresponding layout
file (written in XML).
● Exists in the layout directory of resources.
● Can use the designer to generate this XML for us.
● Can also do it similar to how we did it in Swing, but
less popular in general (ViewGroups)

13. The Manifest File
● Every Android app must have an
AndroidManifest.xml file which is the “glue”
that brings everything together to form an app.
● It names the package for the Android
application
package="com.example.simon.myfirstapp"
● Also says which code files (including Java) are
behind each screen (Activity) in the app.

14. Start of the Manifest File
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
These are the icon, label and theme
of your app and are picked up from
the Resources (res directory)
@style automatically links to
res/values/styles.xml
@string automatically links to
res/values/strings.xml
@drawable
automatically links to
the relevant
res/drawable
directory

15. android:label
android:icon
The font, colour, style, spacing
(i.e. “The look”) of the app is
controlled by
android:style
(in this case AppTheme in style.xml)
This is where your Activity runs.
Here we see MainActivity.java

16. Activities in Manifest File
● Activities must also be defined in the manifest
file.
<activity
android:name=".MyActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
Reference to the
Java file where the
Activity is
implemented.

17. What is <intent-filter> ?
● As previously mentioned each Activity is
capable of being launched as a “self-contained”
unit.
● An <intent-filter> defines where an Activity
can be launched from. (i.e. Where you “intend” it to
be launched from)
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

18. <intent-filter>
The <action> element specifies that this is the "main" entry
point to the application. (Like main in regular Java)
The <category> element specifies that this activity should be
listed in the system's application launcher (to allow users to
launch this activity).
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

19. A First Basic App
Key Parts of an Android App are :
Activity (Java) / Activity Layout (XML)
Manifest
Resource Directories
Next Week :
Activity Lifecycle & GUI Event Handling