ISAC – Android programming

INTERNATIONAL SUMMER ACADEMIC COURSE

UNIVESITY OF NIS

ISAC – Android programming


Introductions into Android programming• SDK (Sowtware developement kit)• DVM(Dalvik Virtual Machine)• JAVA API• Eclipse

Android App Fundamentals The process of creating an android application Android SDK configuration Creating a new virtual device


Setup

Set up your developement environment

Set up AVDs and devices for testing

Install the Android SDK, Android Developement Tools and Android platforms

Create Android Virtual Devices and connect hardware devices for testing

Developement Create your application

Create an Android project with your source code, resources and manifest file


Debugging and testing

Build and run your application

Debugg your application

Build and run your application in debug mode

Debug your application using the Android debugging and logging tools

Test your application

Test your application using emulator or real devices


Publishing

Prepare your application for release

Debugg your application

Configure, build and test your application in release mode

Publicize, sell and distribute your application to users

Android SDK Configuring Android SDK manager Creating virtual devices Getting to know the environment Creating a new Android project and a “Hello world”

application



What is an activity?LayoutsManifestXMLR class


Activity

The basis of android applicationsA single Activity defines a single viewable screen

the actions, not the layoutCan have multiple per applicationEach is a separate entityThey have a structured life cycle

Different events in their life happen either via the user touching buttons or programmatically


Life cycle of an activity


Project components

src – your source codegen – auto-generated code (usually just R.java)Included librariesResources

Drawables (like .png images) Layouts Values (like strings)

Manifest file


XML – Extensible Markup Language

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 itContains IDs of the project resourcesEnforces good software engineeringUse findViewById and Resources object to get

access to the resources Ex. Button b = (Button)findViewById(R.id.button1) Ex. getResources().getString(R.string.hello));


Mafinest 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


UI, layouts and components used in Android apps Layouts

Eclipse has a great UI creator Generates the XML for you

Composed of View objectsCan be specified for portrait and landscape mode

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

Types of layouts: Linear, Relative, Frame...


1. Intents and intent filter1.1. What are intents?

1.2. Starting activities


The following code demonstrates how you can start

another activity via an intent.

# Start the activity connect to the # specified class

Intent i = new Intent(this, ActivityTwo.class); startActivity(i);

2. Intents types2.1. Different types of intents2.2. Explicit IntentsExplicit intents explicitly define the component which

should be called by the Android system, by using the Java class as identifier.

2.3. Implicit IntentsImplicit intents specify the action which should be

performed and optionally data which provides content for the action.

3. Data transfer between activities 3.1. Data transfer to the target

componentBundle extras = getIntent().getExtras(); if (extras == null) { return; } // get data via the key String value1 = extras.getString(Intent.EXTRA_TEXT); if (value1 != null) { // do something with the data }

3.2. Example: Using the share intent

// this runs, for example, after a button clickIntent intent = new Intent(Intent.ACTION_SEND);intent.setType("text/plain"); intent.putExtra(android.content.Intent.EXTRA_TEXT, "News for you!"); startActivity(intent);

3.3. Retrieving result data from a sub-activity

ISAC – Android programming

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