1. Android Dr. Vaishali D. Khairnar IT Department
Terna Engineering College

2. What is Android?
Android is a software stack for mobile devices that includes an operating system, middleware and key applications.

3. OHA (Open Handset Alliance)
A business alliance consisting of 47 companies to develop open standards for mobile devices

4. Phones HTC G1, Droid, Tattoo Motorola Droid (X) Sony Ericsson
Suno S880
Samsung Galaxy

5. Tablets Velocity Micro Cruz Gome FlyTouch Acer beTouch Toshiba Android
SmartBook
Cisco Android Tablet
Dawa D7

6. Android Studio Installation Steps
Step 1: System Requirements
Microsoft® Windows® 8/7/Vista/2003 (32 or 64-bit)
Java JDK5 or later version (jdk1.8.0_101)
Java Runtime Environment (JRE) or later version (jre1.8.0_101)
Set-up Java Development Kit (JDK)
set JAVA_HOME=C:\jdk1.8.0_101
Android Studio (android-studio-bundle windows.exe)
Android Studio is the official IDE for android application development. It works based onIntelliJ IDEA
Link for Android Studio developer.android.com/sdk/index.html

7. launch Android Studio.exe Machine should required installed Java JDK.
Step 2: Installation
launch Android Studio.exe
Machine should required installed Java JDK.
By clicking on next complete the wizard for Android Studio.
Errors
JDK error
Install latest version of jdk and configure it.
HAXM installation failed.
Download HAXM from link (haxm-windows_v6_0_3.zip)
Extra it and run (intelhaxm-android.exe and haxm_check.exe)

11. Hello Word Example
App>res>layout>Activity_main.xml

12. Architecture

13. Android S/W Stack - Application
Android provides a set of core applications:
Client
SMS Program
Calendar
Maps
Browser
Contacts
Etc
All applications are written using the Java language.

14. Application components are the essential building blocks of an Android application.
These components are loosely coupled by the application manifest file AndroidManifest.xml that describes each component of the application and how they interact.
Components
Description
Activities
They dictate the UI and handle the user interaction to the smart phone screen
Services
They handle background processing associated with an application.
Broadcast Receivers
They handle communication between Android OS and applications.
Content Providers
They handle data and database management issues.

15. Additional Components: used in the construction of above mentioned entities, their logic, and wiring between them etc.
Components
Description
Fragments
Represents a portion of user interface in an Activity.
Views
UI elements that are drawn on-screen including buttons, lists forms etc.
Layouts
View hierarchies that control screen format and appearance of the views.
Intents
Messages wiring components together.
Resources
External elements, such as strings, constants and drawable pictures.
Manifest
Configuration file for the application.

16. Android S/W Stack – App Framework
Enabling and simplifying the reuse of components
Developers have full access to the same framework APIs used by the core applications.
Users are allowed to replace components.

17. Android S/W Stack – App Framework (Cont)
Features
Feature
Role
View
System
Used to build an application, including lists, grids, text boxes, buttons, and embedded web browser
Content
Provider
Enabling applications to access data from other applications or to share their own data
Resource
Manager
Providing access to non-code resources (localized strings, graphics, and layout files)
Notification Manager
Enabling all applications to display customer alerts in the
status bar
Activity
Managing the lifecycle of applications and providing
a common navigation backstack

18. Android S/W Stack - Libraries
Including a set of C/C++ libraries used by components of the Android system
Exposed to developers through the Android application framework

19. Android S/W Stack - Runtime
Core Libraries
Providing most of the functionality available in the core libraries of the Java language
APIs
Data Structures
Utilities
File Access
Network Access
Graphics
Etc

20. Android S/W Stack – Runtime (Cont)
Dalvik Virtual Machine
Providing environment on which every Android application runs
Each Android application runs in its own process, with its own instance of the Dalvik VM.
Dalvik has been written such that a device can run multiple VMs efficiently.
Register-based virtual machine

21. Android S/W Stack – Runtime (Cont)
Dalvik Virtual Machine (Cont)
Executing the Dalvik Executable (.dex) format
.dex format is optimized for minimal memory footprint.
Compilation
Relying on the Linux Kernel for:
Threading
Low-level memory management

22. Android S/W Stack – Linux Kernel
Relying on Linux Kernel 2.6 for core system services
Memory and Process Management
Network Stack
Driver Model
Security
Providing an abstraction layer between the H/W and the rest of the S/W stack

23. Create Android Application (HelloWorld)
Click on Start a new Android Studio Project

24. Next, follow the instructions provided and keep all other entries as default till the final step. Once your project is created successfully, you will have following project screen

26. Anatomy of Android Application
S.N.
Folder, File & Description 1
src This contains the .java source files for your project. By default, it includes a MainActivity.java source file having an activity class that runs when your app is launched using the app icon. 2
gen This contains the .R file, a compiler-generated file that references all the resources found in your project. You should not modify this file. 3
bin This folder contains the Android package files .apk built by the ADT during the build process and everything else needed to run an Android application. 4
res/drawable-hdpi This is a directory for drawable objects that are designed for high-density screens. 5
res/layout This is a directory for files that define your app's user interface. 6
res/values This is a directory for other various XML files that contain a collection of resources, such as strings and colours definitions. 7
AndroidManifest.xml This is the manifest file which describes the fundamental characteristics of the app and defines each of its components.

27. The Main Activity File
The main activity code is a Java file MainActivity.java. This is the actual application file which ultimately gets converted to a Dalvik executable and runs your application. Following is the default code generated by the application wizard for Hello World! application −
package com.example.hod_it.helloworld; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } }
R.layout.activity_main refers to the activity_main.xml file located in the res/layout folder. The onCreate() method is one of many methods that are figured when an activity is loaded.

28. The Manifest File
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android=" package="com.example.hod_it.helloworld"> <application android:allowBackup="true" android:supportsRtl="true" <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
Whatever component you develop as a part of your application, you must declare all its components in a manifest.xml which resides at the root of the application project directory. This file works as an interface between Android OS and your application, so if you do not declare your component in this file, then it will not be considered by the OS.
The Strings File
The R File
The Layout File

29. Android Activities Callback Description onCreate()
This is the first callback and called when the activity is first created.
onStart()
This callback is called when the activity becomes visible to the user.
onResume()
This is called when the user starts interacting with the application.
onPause()
The paused activity does not receive user input and cannot execute any code and called when the current activity is being paused and the previous activity is being resumed.
onStop()
This callback is called when the activity is no longer visible.
onDestroy()
This callback is called before the activity is destroyed by the system.
onRestart()
This callback is called when the activity restarts after stopping it.

30. Example

31. Android Intents
Intents are asynchronous messages which allow application components to request functionality from other Android components.
Intents allow you to interact with components from the same applications as well as with components contributed by other applications.
For example, an activity can start an external activity for taking a picture.
Intent can be used to:
Start an Activity
Start sub-activity.
Start a Service.

32. Types of Intent
Explicit Intent: An application can define the target component directly in the intent
Implicit Intent: Ask the Android system to evaluate registered components based on the intent data.

33. Explicit Intent example

34. Steps
Create "Empty Activity" project named ExplicitIntentExample

36. By double-clicking on the components on the interface, you can set the ID and text  for them:
EditText 1: ID: text_firstName
Properties
layout_width: fill_parent
EditText 2: ID: text_lastName
TextView: ID: text_feedback
Text: <Feedback>
Properties:
gravity: center_horizontal

37. Button: ID: button_greeting Text: Show Greeting Properties:
onClick: showGreeting

38. activity_explicit_intent.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android=" xmlns:tools=" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.hod_it.explicitintentexample.ExplicitIntentActivity"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceLarge" android:text="<Feedback>" android:layout_alignParentBottom="true" android:layout_marginBottom="92dp" android:singleLine="true" android:layout_centerHorizontal="true" android:textAlignment="center" android:gravity="center_horizontal"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Show Greeting" android:onClick="showGreeting" android:layout_centerHorizontal="true" android:layout_marginBottom="68dp" /> <EditText android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_marginTop="40dp" /> <EditText android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_marginTop="51dp" /> </RelativeLayout>

39. When users click the button, the program will call a other Activity displays a greeting. You need to create an Activity with name GreetingActivity.

41. Change the attributes for components on the interface:
TextView ID: text_greeting
Text: <Greeting>
Properties:
layout_width: fill_parent
gravity: center_horizontal
Button: ID: button_back
Properties
onClick: backClicked

42. activity_greeting.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android=" xmlns:tools=" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.hod_it.explicitintentexample.GreetingActivity"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceLarge" android:text="<Greeting>" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:layout_marginTop="65dp" android:textAlignment="center" android:gravity="center_horizontal"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Back" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true" android:layout_marginBottom="165dp" android:onClick="backClicked" /> </RelativeLayout>

43. ExplicitIntentActivity.java
package com.example.hod_it.explicitintentexample; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.app.Activity; import android.content.Intent; import android.view.View; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class ExplicitIntentActivity extends AppCompatActivity { private EditText textFirstName; private EditText textLastName; private TextView textFeedback; public static final int MY_REQUEST_CODE = 100; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_explicit_intent); this.textFirstName = (EditText)this.findViewById(R.id.text_firstname); this.textLastName = (EditText)this.findViewById(R.id.text_lastname); this.textFeedback = (TextView)this.findViewById(R.id.text_feedback); } // When 'Greeting Activity' completed, it sends back a feedback. // (If you have started it by startActivityForResult()) @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (resultCode == Activity.RESULT_OK && requestCode == MY_REQUEST_CODE ) { String feedback = data.getStringExtra("feedback"); this.textFeedback.setText(feedback); } else { this.textFeedback.setText("!?"); } } // The method is called when the user clicks on "Show Greeting" button. public void showGreeting(View view) { String firstName= this.textFirstName.getText().toString(); String lastName= this.textLastName.getText().toString(); Intent intent = new Intent(this,GreetingActivity.class); intent.putExtra("firstName", firstName); intent.putExtra("lastName", lastName); // Start Activity and no need feedback // this.startActivity(intent); // Start Activity and get feedback this.startActivityForResult(intent, MY_REQUEST_CODE); } }

44. GreetingActivity.java
package com.example.hod_it.explicitintentexample; import android.app.Activity; import android.content.Intent; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.TextView; public class GreetingActivity extends AppCompatActivity { private String firstName; private String lastName; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_greeting); // Intent is passed into Intent intent = this.getIntent(); this.firstName= intent.getStringExtra("firstName"); this.lastName = intent.getStringExtra("lastName"); String greeting = "Hello "+ firstName+" "+ lastName; TextView textGreeting =(TextView) this.findViewById(R.id.text_greeting); textGreeting.setText(greeting); } // When completed this Activity, send feedback to the caller. @Override public void finish() { // Prepare data intent Intent data = new Intent(); data.putExtra("feedback", "I'm "+ this.firstName+", Hi!"); // Activity finished ok, return the data this.setResult(Activity.RESULT_OK, data); super.finish(); } // The method is called when the user clicks the Back button. public void backClicked(View view) { // Calling onBackPressed() // Gọi phương thức onBackPressed() this.onBackPressed(); } }

45. AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android=" package="com.example.hod_it.explicitintentexample"> <application android:allowBackup="true" android:supportsRtl="true" <activity android:name=".ExplicitIntentActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".GreetingActivity"></activity> </application> </manifest>

46. Home-Work: Add Middle Name in First Screen Display First Name, Middle Name and Last Name
With Message Hello How are you!!!.

47. Implicit intent
Implicit intents: These do not specify a target component, but include enough information for the system to determine which of the available components is best to run for that intent.
Consider an app that lists the available restaurants near you. When you click a particular restaurant option, the application has to ask another application to display the route to that restaurant. To achieve this, it could either send an explicit intent directly to the Google Maps application, or send an implicit intent, which would be delivered to any application that provides the Maps’ functionality (e.g., Google Maps, Yahoo Maps).

48. Example with the implicit intent
In this example, you will click a Button which will show you a website by URL, you create an  implicitly Intent, Intent sent to the Android system to decide which  components will be  opened , maybe in your equipment installs many different browsers (Firefox, Chrome, ..), the device will open it in your default browser or your preferred browser
In addition examples also include: Send an