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L6:Android Studio 3.0 Installation,HelloWorld in android in Hindi By University Academy

L6:Android Studio 3.0 Installation,HelloWorld in android in Hindi By University Academy
L6:Android Studio 3.0 Installation,HelloWorld in android in Hindi By University Academy

Let us start actual programming with Android Framework. Before you start writing your first example using Android SDK, you have to make sure that you have set-up your Android development environment properly as explained in Android – Environment Set-up tutorial. I also assume that you have a little bit working knowledge with Android studio.
So let us proceed to write a simple Android Application which will print “Hello World!”.

Create Android Application

The first step is to create a simple Android Application using Android studio. When you click on Android studio icon, it will show screen as shown below

Hello Android Wizard

You can start your application development by calling start a new android studio project. in a new installation frame should ask Application name, package information and location of the project.−

Hello Android Project

After entered application name, it going to be called select the form factors your application runs on, here need to specify Minimum SDK, in our tutorial, I have declared as API23: Android 6.0(Mashmallow) −

Hello Android Project

The next level of installation should contain selecting the activity to mobile, it specifies the default layout for Applications.

Hello Android Project

At the final stage it going to be open development tool to write the application code.

Hello Android Project

Anatomy of Android Application

Before you run your app, you should be aware of a few directories and files in the Android project −

Android Directory Structure

Sr.No. Folder, File & Description
1
Java
This contains the .java source files for your project. By default, it includes an MainActivity.java source file having an activity class that runs when your app is launched using the app icon.
2
res/drawable-hdpi
This is a directory for drawable objects that are designed for high-density screens.
3
res/layout
This is a directory for files that define your app’s user interface.
4
res/values
This is a directory for other various XML files that contain a collection of resources, such as strings and colours definitions.
5
AndroidManifest.xml
This is the manifest file which describes the fundamental characteristics of the app and defines each of its components.
6
Build.gradle
This is an auto generated file which contains compileSdkVersion, buildToolsVersion, applicationId, minSdkVersion, targetSdkVersion, versionCode and versionName
Following section will give a brief overview of the important application files.

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.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);
}
}
Here, 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.

The Manifest File

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. For example, a default manifest file will look like as following file −
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.tutorialspoint7.myapplication">

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">

<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>
Here <application>…</application> tags enclosed the components related to the application. Attribute android:icon will point to the application icon available under res/drawable-hdpi. The application uses the image named ic_launcher.png located in the drawable folders
The <activity> tag is used to specify an activity and android:name attribute specifies the fully qualified class name of the Activity subclass and the android:label attributes specifies a string to use as the label for the activity. You can specify multiple activities using <activity> tags.
The action for the intent filter is named android.intent.action.MAIN to indicate that this activity serves as the entry point for the application. The categoryfor the intent-filter is named android.intent.category.LAUNCHER to indicate that the application can be launched from the device’s launcher icon.
The @string refers to the strings.xml file explained below. Hence, @string/app_name refers to the app_name string defined in the strings.xml file, which is “HelloWorld”. Similar way, other strings get populated in the application.
Following is the list of tags which you will use in your manifest file to specify different Android application components −
  • <activity>elements for activities
  • <service> elements for services
  • <receiver> elements for broadcast receivers
  • <provider> elements for content providers

The Strings File

The strings.xml file is located in the res/values folder and it contains all the text that your application uses. For example, the names of buttons, labels, default text, and similar types of strings go into this file. This file is responsible for their textual content. For example, a default strings file will look like as following file −
<resources>
<string name="app_name">HelloWorld</string>
<string name="hello_world">Hello world!</string>
<string name="menu_settings">Settings</string>
<string name="title_activity_main">MainActivity</string>
</resources>

The Layout File

The activity_main.xml is a layout file available in res/layout directory, that is referenced by your application when building its interface. You will modify this file very frequently to change the layout of your application. For your “Hello World!” application, this file will have following content related to default layout −
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:padding="@dimen/padding_medium"
android:text="@string/hello_world"
tools:context=".MainActivity" />

</RelativeLayout>
This is an example of simple RelativeLayout which we will study in a separate chapter. The TextView is an Android control used to build the GUI and it have various attributes like android:layout_widthandroid:layout_height etc which are being used to set its width and height etc.. The @string refers to the strings.xml file located in the res/values folder. Hence, @string/hello_world refers to the hello string defined in the strings.xml file, which is “Hello World!”.

Running the Application

Let’s try to run our Hello World! application we just created. I assume you had created your AVD while doing environment set-up. To run the app from Android studio, open one of your project’s activity files and click Run Eclipse Run Icon icon from the tool bar. Android studio installs the app on your AVD and starts it and if everything is fine with your set-up and application, it will display following Emulator window −

Android Hello World

Congratulations!!! you have developed your first Android Application and now just keep following rest of the tutorial step by step to become a great Android Developer. All the very best.

L5:Android Tutorial For Beginners,Android Studio 3.0 &JDK installation in hindi by University Academ

L5:Android Tutorial For Beginners,Android Studio 3.0 &JDK installation in hindi by University Academ
L5:Android Tutorial For Beginners,Android Studio 3.0 &JDK installation in hindi by University Academ 

You will be glad to know that you can start your Android application development on either of the following operating systems −
  • Microsoft Windows XP or later version.
  • Mac OS X 10.5.8 or later version with Intel chip.
  • Linux including GNU C Library 2.7 or later.
Second point is that all the required tools to develop Android applications are freely available and can be downloaded from the Web. Following is the list of software’s you will need before you start your Android application programming.
  • Java JDK5 or later version
  • Android Studio
Here last two components are optional and if you are working on Windows machine then these components make your life easy while doing Java based application development. So let us have a look how to proceed to set required environment.

Set-up Java Development Kit (JDK)

You can download the latest version of Java JDK from Oracle’s Java site − Java SE Downloads. You will find instructions for installing JDK in downloaded files, follow the given instructions to install and configure the setup. Finally set PATH and JAVA_HOME environment variables to refer to the directory that contains java and javac, typically java_install_dir/bin and java_install_dir respectively.
If you are running Windows and installed the JDK in C:jdk1.8.0_102, you would have to put the following line in your C:autoexec.bat file.
set PATH=C:jdk1.8.0_102bin;%PATH%
set JAVA_HOME=C:jdk1.8.0_102
Alternatively, you could also right-click on My Computer, select Properties, then Advanced, then Environment Variables. Then, you would update the PATH value and press the OK button.
On Linux, if the SDK is installed in /usr/local/jdk1.8.0_102 and you use the C shell, you would put the following code into your .cshrc file.
setenv PATH /usr/local/jdk1.8.0_102/bin:$PATH
setenv JAVA_HOME /usr/local/jdk1.8.0_102
Alternatively, if you use Android studio, then it will know automatically where you have installed your Java.

Android IDEs

There are so many sophisticated Technologies are available to develop android applications, the familiar technologies, which are predominantly using tools as follows

L4:Android Studio 3.0 Tutorial For Beginners,Advanced Component of Android in Hindi by University

L4:Android Studio 3.0 Tutorial For Beginners,Advanced Component of Android in Hindi by University
L4:Android Studio 3.0 Tutorial For Beginners,Advanced Component of Android in Hindi by University

pplication 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.
There are following four main components that can be used within an Android application −
Sr.No Components & Description
1
Activities
They dictate the UI and handle the user interaction to the smart phone screen.
2
Services
They handle background processing associated with an application.
3
Broadcast Receivers
They handle communication between Android OS and applications.
4
Content Providers
They handle data and database management issues.

Activities

An activity represents a single screen with a user interface,in-short Activity performs actions on the screen. For example, an email application might have one activity that shows a list of new emails, another activity to compose an email, and another activity for reading emails. If an application has more than one activity, then one of them should be marked as the activity that is presented when the application is launched.
An activity is implemented as a subclass of Activity class as follows −
public class MainActivity extends Activity {
}

Services

A service is a component that runs in the background to perform long-running operations. For example, a service might play music in the background while the user is in a different application, or it might fetch data over the network without blocking user interaction with an activity.
A service is implemented as a subclass of Service class as follows −
public class MyService extends Service {
}

Broadcast Receivers

Broadcast Receivers simply respond to broadcast messages from other applications or from the system. For example, applications can also initiate broadcasts to let other applications know that some data has been downloaded to the device and is available for them to use, so this is broadcast receiver who will intercept this communication and will initiate appropriate action.
A broadcast receiver is implemented as a subclass of BroadcastReceiverclass and each message is broadcaster as an Intent object.
public class MyReceiver  extends  BroadcastReceiver {
public void onReceive(context,intent){}
}

Content Providers

A content provider component supplies data from one application to others on request. Such requests are handled by the methods of the ContentResolverclass. The data may be stored in the file system, the database or somewhere else entirely.
A content provider is implemented as a subclass of ContentProvider class and must implement a standard set of APIs that enable other applications to perform transactions.
public class MyContentProvider extends  ContentProvider {
public void onCreate(){}
}
We will go through these tags in detail while covering application components in individual chapters.

Additional Components

There are additional components which will be used in the construction of above mentioned entities, their logic, and wiring between them. These components are −
S.No Components & Description
1
Fragments
Represents a portion of user interface in an Activity.
2
Views
UI elements that are drawn on-screen including buttons, lists forms etc.
3
Layouts
View hierarchies that control screen format and appearance of the views.
4
Intents
Messages wiring components together.
5
Resources
External elements, such as strings, constants and drawable pictures.
6
Manifest
Configuration file for the application.

L3:Android Studio 3.0 kotlin Tutorial,Core Component of Android in hindi by University Academy

L3:Android Studio 3.0 kotlin Tutorial,Core Component of Android in hindi by University Academy
L3:Android Studio 3.0 kotlin Tutorial,Core Component of Android in hindi by University Academy

Android Core Building Blocks

android components

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

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

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.

AndroidManifest.xml

It contains informations 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.

L2:Android Studio 3.0 kotlin Tutorial,Mobile App Development,Features of Android in Hindi

L2:Android Studio 3.0 kotlin Tutorial,Mobile App Development,Features of Android in Hindi
L2:Android Studio 3.0 kotlin Tutorial,Mobile App Development,Features of Android in Hindi 

Android Architecture

android architecture or Android software stack is categorized into five parts:
  1. linux kernel
  2. native libraries (middleware),
  3. Android Runtime
  4. Application Framework
  5. Applications
Let’s see the android architecture first.

android software stack, architecture 

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.

2) Native Libraries

On the top of linux kernel, their are Native libraries such as WebKit, OpenGL, FreeType, SQLite, Media, C runtime library (libc) etc.
The WebKit library is responsible for browser support, SQLite is for database, FreeType for font support, Media for playing and recording audio and video formats.

3) Android Runtime

In android runtime, there are core libraries and DVM (Dalvik Virtual Machine) which is responsible to run android application. DVM is like JVM but it is optimized for mobile devices. It consumes less memory and provides fast performance.

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.

5) Applications

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.

L1:Android Studio 3.0 kotlin Tutorial,Mobile App Development,Architecture of Android in hindi

L1:Android Studio 3.0 kotlin Tutorial,Mobile App Development,Architecture of Android in hindi
L1:Android Studio 3.0 kotlin Tutorial,Mobile App Development,Architecture of Android in hindi

What is Android?

Android is an open source and Linux-based Operating System for mobile devices such as smartphones and tablet computers. Android was developed by the Open Handset Alliance, led by Google, and other companies.
Android offers a unified approach to application development for mobile devices which means developers need only develop for Android, and their applications should be able to run on different devices powered by Android.
The first beta version of the Android Software Development Kit (SDK) was released by Google in 2007 where as the first commercial version, Android 1.0, was released in September 2008.
On June 27, 2012, at the Google I/O conference, Google announced the next Android version, 4.1 Jelly Bean. Jelly Bean is an incremental update, with the primary aim of improving the user interface, both in terms of functionality and performance.
The source code for Android is available under free and open source software licenses. Google publishes most of the code under the Apache License version 2.0 and the rest, Linux kernel changes, under the GNU General Public License version 2.

Why Android ?

Why Android

Features of Android

Android is a powerful operating system competing with Apple 4GS and supports great features. Few of them are listed below −
Sr.No. Feature & Description
1
Beautiful UI
Android OS basic screen provides a beautiful and intuitive user interface.
2
Connectivity
GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi, LTE, NFC and WiMAX.
3
Storage
SQLite, a lightweight relational database, is used for data storage purposes.
4
Media support
H.263, H.264, MPEG-4 SP, AMR, AMR-WB, AAC, HE-AAC, AAC 5.1, MP3, MIDI, Ogg Vorbis, WAV, JPEG, PNG, GIF, and BMP.
5
Messaging
SMS and MMS
6
Web browser
Based on the open-source WebKit layout engine, coupled with Chrome’s V8 JavaScript engine supporting HTML5 and CSS3.
7
Multi-touch
Android has native support for multi-touch which was initially made available in handsets such as the HTC Hero.
8
Multi-tasking
User can jump from one task to another and same time various application can run simultaneously.
9
Resizable widgets
Widgets are resizable, so users can expand them to show more content or shrink them to save space.
10
Multi-Language
Supports single direction and bi-directional text.
11
GCM
Google Cloud Messaging (GCM) is a service that lets developers send short message data to their users on Android devices, without needing a proprietary sync solution.
12
Wi-Fi Direct
A technology that lets apps discover and pair directly, over a high-bandwidth peer-to-peer connection.
13
Android Beam
A popular NFC-based technology that lets users instantly share, just by touching two NFC-enabled phones together.

Android Applications

Android applications are usually developed in the Java language using the Android Software Development Kit.
Once developed, Android applications can be packaged easily and sold out either through a store such as Google PlaySlideMEOpera Mobile StoreMobangoF-droid and the Amazon Appstore.
Android powers hundreds of millions of mobile devices in more than 190 countries around the world. It’s the largest installed base of any mobile platform and growing fast. Every day more than 1 million new Android devices are activated worldwide.
This tutorial has been written with an aim to teach you how to develop and package Android application. We will start from environment setup for Android application programming and then drill down to look into various aspects of Android applications.

Categories of Android applications

There are many android applications in the market. The top categories are −

Categories

History of Android

The code names of android ranges from A to N currently, such as Aestro, Blender, Cupcake, Donut, Eclair, Froyo, Gingerbread, Honeycomb, Ice Cream Sandwitch, Jelly Bean, KitKat, Lollipop and Marshmallow. Let’s understand the android history in a sequence.

Jistory

What is API level?

API Level is an integer value that uniquely identifies the framework API revision offered by a version of the Android platform.


Platform Version API Level VERSION_CODE
Android 6.0 23 MARSHMALLOW
Android 5.1 22 LOLLIPOP_MR1
Android 5.0 21 LOLLIPOP
Android 4.4W 20 KITKAT_WATCH KitKat for Wearables Only
Android 4.4 19 KITKAT
Android 4.3 18 JELLY_BEAN_MR2
Android 4.2, 4.2.2 17 JELLY_BEAN_MR1
Android 4.1, 4.1.1 16 JELLY_BEAN
Android 4.0.3, 4.0.4 15 ICE_CREAM_SANDWICH_MR1
Android 4.0, 4.0.1, 4.0.2 14 ICE_CREAM_SANDWICH
Android 3.2 13 HONEYCOMB_MR2
Android 3.1.x 12 HONEYCOMB_MR1
Android 3.0.x 11 HONEYCOMB
Android 2.3.4
Android 2.3.3
10 GINGERBREAD_MR1
Android 2.3.2
Android 2.3.1
Android 2.3
9 GINGERBREAD
Android 2.2.x 8 FROYO
Android 2.1.x 7 ECLAIR_MR1
Android 2.0.1 6 ECLAIR_0_1
Android 2.0 5 ECLAIR
Android 1.6 4 DONUT
Android 1.5 3 CUPCAKE
Android 1.1 2 BASE_1_1
Android 1.0 1 BASE
 
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