MOBILE APPLICATION DEVELOPMENT

1. 20IT601PE-
MOBILE APPLICATION
DEVELOPMENT

2. UNIT I
ANDROID OVERVIEW
Introduction – Android SDK features – OHA
– Development framework – Getting started –
developing for android, mobile devices - ADT –
Creating an applications and activities -
Application manifest – Android Application Life
Cycle – Understanding application priority -
Externalizing resources – Android application
class – Android Activities

3. Development framework
 In general, a framework is a real or conceptual structure
intended to serve as a support or guide for the building of
something that expands the structure into something useful.
 An Android application framework is a software toolkit that
enables app developers to piece together a finished product
that meets the requirements of its proprietor.

4. Development framework
 A framework provides the bones of an application, to be
fleshed out with graphics, animation, special features and
functionality.
 The Application Framework layer provides many higher-
level services to applications in the form of Java classes.

5. Android architecture or Android software stack is
categorized into five parts:
Linux kernel
Native libraries (middleware)
Android Runtime
Application Framework
Application Layer

7. 1) Linux kernel
• It is the heart of android architecture that exists
at the root of android architecture.
• Linux kernel is responsible for device drivers,
power management, memory management,
device management and resource access.

8. 2) Native Libraries
• Running on the top of linux kernel, Native libraries such as
WebKit, OpenGL, FreeType, SQLite, Media, C runtime
library (libc) etc.
• The WebKit library is responsible for browser support and
Internet security;
• SQLite is for database,
• FreeType for font support,
• Media for playing and recording audio and video formats.

9. Some key core Android libraries available to the Android
developer is as follows −
• android.app − Provides access to the application model and is
the cornerstone of all Android applications.
• android.content − Facilitates content access, publishing and
messaging between applications and application components.
• android.database − Used to access data published by content
providers and includes SQLite database management classes.
• android.opengl − A Java interface to the OpenGL ES 3D
graphics rendering API.

10. • android.os − Provides applications with access to standard
operating system services including messages, system services and
inter-process communication.
• android.text − Used to render and manipulate text on a device
display.
• android.view − The fundamental building blocks of application
user interfaces.
• android.widget − A rich collection of pre-built user interface
components such as buttons, labels, list views, layout managers,
radio buttons etc.
• android.webkit − A set of classes intended to allow web-browsing
capabilities to be built into applications.

11. 3) Android Runtime
 In android runtime, there are core libraries and DVM
(Dalvik Virtual Machine) which is responsible to run
android application.
 One of the key elements of Android is the Dalvik VM,
Android uses its own custom VM designed to ensure that
multiple instances run efficiently on a single device.
 DVM is like JVM but it is optimized for mobile devices.
 The Dalvik VM makes use of Linux core features like
memory management and multi-threading, which is
intrinsic in the Java language.
 It consumes less memory and provides fast performance.

12. 4) Android Framework
 On the top of Native libraries and android runtime, there
is android framework.
 Android framework includes Android API's such as UI
(User Interface), telephony, resources, locations, Content
Providers (data) and package managers.
 It provides a lot of classes and interfaces for android
application development.

13. 5) Application Layer
 On the top of android framework, there are applications.
 All applications such as home, contact, settings, games,
browsers are using android framework that uses android
runtime and libraries.
 Android runtime and native libraries are using linux
kernal.

14. Android Core Building Blocks
 An android component is simply a piece of code that has
a well defined life cycle e.g. Activity, Receiver, and
Service etc.
 The core building blocks or fundamental components of
android are activities, views, intents, services, content
providers, fragments and AndroidManifest.xml.

15.  Activity
An activity is a class that represents a single screen.
It is like a Frame in AWT.
 View
A view is the UI element such as button, label, text field etc.
Anything that you see is a view.
 Intent
Intent is used to invoke components. It is mainly used to:
• Start the service
• Launch an activity
• Display a web page
• Display a list of contacts
• Broadcast a message
• Dial a phone call etc.

16. • For example, write the following code to view the
webpage.
Intent intent=new Intent (Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://www.javatpoint.com"));
startActivity(intent);

17. Service
• Service is a background process that can run for a long time.
• There are two types of services local and remote.
• Local service is accessed from within the application
whereas remote service is accessed remotely from other
applications running on the same device.
Content Provider
• Content Providers are used to share data between the
applications.
• Fragment
• Fragments are like parts of activity.
• An activity can display one or more fragments on the screen
at the same time.

18. AndroidManifest.xml
• It contains information about activities, content providers,
permissions etc.
• It is like the web.xml file in Java EE.
Android Virtual Device (AVD)
• It is used to test the android application without the need
for mobile or tablet etc.
• It can be created in different configurations to emulate
different types of real devices.

19. Android Activity Lifecycle
• Activity is one of the building blocks of Android OS.
• Activity is a screen that user interact with.
• Every Activity in android has lifecycle like created,
started, resumed, paused, stopped or destroyed.
• Activity is a class pre-written in Java Programming. An
activity is the single screen in android. It is like
window or frame of Java.

20. Android Activity Lifecycle methods
The 7 lifecycle methods of Activity describes how activity will
behave at different states.
•onCreate()
•onStart()
•onResume()
•onPause()
•onStop()
•onRestart()
•onDestroy

21. Android Activity Lifecycle methods
•onCreate() – Called when the activity is first created
•onStart() – Called just after it’s creation or by restart
method after onStop(). Here Activity start becoming visible
to user
•onResume() – Called when Activity is visible to user and
user can interact with it
•onPause() – Called when Activity content is not visible
because user resume previous activity

22. Android Activity Lifecycle methods
•onStop() – Called when activity is not visible to user
because some other activity takes place of it
•onRestart() – Called when user comes on screen or resume
the activity which was stopped
•onDestroy – Called when Activity is not in background

29. EXAMPLE
Following is the content of the modified main activity
file src/com.example.helloworld/MainActivity.java.
This file includes each of the fundamental life cycle
methods.
The Log.d() method has been used to generate log
messages −

30. package com.example.helloworld;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
public class MainActivity extends Activity {
String msg = "Android : ";
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(msg, "The onCreate() event"); }
/** Called when the activity is about to become visible. */ @Override
protected void onStart() {
super.onStart();
Log.d(msg, "The onStart() event"); }

31. /** Called when the activity has become visible. */
@Override
protected void onResume() {
super.onResume();
Log.d(msg, "The onResume() event"); }
/** Called when another activity is taking focus. */
@Override
protected void onPause() {
super.onPause();
Log.d(msg, "The onPause() event"); }

32. /** Called when the activity is no longer visible. */
@Override
protected void onStop() {
super.onStop();
Log.d(msg, "The onStop() event"); }
/** Called just before the activity is destroyed. */
@Override
public void onDestroy() {
super.onDestroy();
Log.d(msg, "The onDestroy() event");
} }

33. ANDROID DEVELOPMENT TOOLS
• Android Development Tools (ADT) is a plug-in for the
Eclipse IDE that is designed to give you a powerful,
integrated environment in which to build Android
applications.
• ADT is the Android Developer Tools plug-in for Eclipse.
• ADT is about the useful code stuff: for example the libraries,
packages.
• The ADT plug-in for Eclipse uses the SDK tools as part of
its work.

34. ADT vs Android SDK
• The Android SDK contains the tools and
related files necessary to build an Android
application.
• SDK is actually about the tools: for example
Debugging.

35. Android Development Tools (ADT)
ADT plug-in incorporates many of the tools into the
Eclipse IDE, where you can access them from the DDMS
perspective, including the following:
Android Virtual Device and SDK Managers
Android Emulator
Dalvik Debug Monitoring Service (DDMS)
Android Debug Bridge (ADB)
Android Asset Packaging Tool (AAPT)
SQLite3
MkSDCard

36. Android Virtual Device and SDK Managers
• Used to create and manage AVDs and to download
SDK packages, respectively.
• The AVD hosts an Emulator running on a particular
build of Android,
• It specify the supported SDK version, screen
resolution, amount of SD card storage available, and
available hardware capabilities (such as touchscreens
and GPS).

37. Android Emulator
• Use the Emulator to test and debug your Android
applications
Dalvik Debug Monitoring Service (DDMS)
• Use the DDMS to monitor and control the Emulators on
which you’re debugging your applications.
Android Debug Bridge (ADB)
• A client-server application that provides a link to virtual and
physical devices. It lets you copy files, install compiled
application packages (.apk), and run shell commands.

38. Android Asset Packaging Tool (AAPT)
• Constructs the distributable Android package fi les (.apk).
SQLite3
• A database tool that you can use to access the SQLite
database fi les created and used by Android.
MkSDCard
• Creates an SD card disk image that can be used by the
Emulator to simulate an external storage card.

39. Creating an Applications and Activities
• Used to create and manage AVDs and to download
SDK packages, respectively.
• The AVD hosts an Emulator running on a particular
build of Android,
• It specify the supported SDK version, screen
resolution, amount of SD card storage available, and
available hardware capabilities (such as touchscreens
and GPS).