android and its significance

7/31/2019 ANDROID and Its Significance

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Android Application Development Training Tutorial

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ANDROID

Android is a software stack for mobile devices that includes an operating system, middlewareand key applications.

AndroidManifest.xml, an XML file describing the application being built and what

componentsactivities, services, etc.are being supplied by that application

build.xml, an Ant1 script for compiling the application and installing it on the device

default. properties, a property file used by the Ant build script

bin/ holds the application once it is compiled

libs/ holds any third-party Java JARs your application requires

src/ holds the Java source code for the application res/ holds resources, such as icons, GUI layouts, and the like, that get packaged with the

compiled Java in the application

assets/ holds other static files you wish packaged with the application for deployment onto

the device

Features

Application framework enabling reuse and replacement of components Dalvik virtual machine optimized for mobile devices Integrated browser based on the open sourceWebKitengine Optimized graphics powered by a custom 2D graphics library; 3D graphics based on the

OpenGL ES 1.0 specification (hardware acceleration optional)

SQLite for structured data storage Media support for common audio, video, and still image formats (MPEG4, H.264, MP3,

AAC, AMR, JPG, PNG, GIF)

GSM Telephony (hardware dependent) Bluetooth, EDGE, 3G, and WiFi (hardware dependent) Camera, GPS, compass, and accelerometer (hardware dependent) Rich development environment including a device emulator, tools for debugging,

memory and performance profiling, and a plugin for the Eclipse IDE

Activity lifecycle

An activity, generally speaking, is in one of four states at any point in time:

Active: The activity was started by the user, is running, and is in the foreground. This is

what youre used to thinking of in terms ofyour activitys operation.

Paused: The activity was started by the user, is running, and is visible, but a notification

or something is overlaying part of the screen. During this time, the user can see your

activity but may not be able to interact with it. For example, if a call comes in, the user
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will get the opportunity to take the call or ignore it.

Stopped: The activity was started by the user, is running, but it is hidden by other activities

that have been launched or switched to. Your application will not be able to present

anything meaningful to the user directly, only by way of a Notification.

Dead: Either the activity was never started (e.g., just after a phone reset) or the activity was

terminated, perhaps due to lack of available memory.

Intent filters

An Intent object can explicitly name a target component. If it does, Android finds that

component (based on the declarations in the manifest file) and activates it. But if a target is

not explicitly named, Android must locate the best component to respond to the intent. It

does so by comparing the Intent object to the intent filters of potential targets. A component's

intent filters inform Android of the kinds of intents the component is able to handle.

User Interface

In an Android application, the user interface is built usingViewandViewGroupobjects.

Widgets

A widget is a View object that serves as an interface for interaction with the user. Android

provides a set of fully implemented widgets, like buttons, checkboxes, and text-entry fields, so

you can quickly build your UI. Some widgets provided by Android are more complex, like a

date picker, a clock, and zoom controls.

XML-Extensible markup language.

Creating Menus

Menus are an important part of an application that provide a familiar interface for the user to

access application functions and settings. Android offers an easy programming interface foryou to provide application menus in your application.

Android provides three types of application menus:

Options Menu

The primary menu for an Activity, which appears when the user presses the device

MENU key. Within the Options Menu are two groups:

Icon Menu
http://developer.android.com/reference/android/view/View.htmlhttp://developer.android.com/reference/android/view/View.htmlhttp://developer.android.com/reference/android/view/View.htmlhttp://developer.android.com/reference/android/view/ViewGroup.htmlhttp://developer.android.com/reference/android/view/ViewGroup.htmlhttp://developer.android.com/reference/android/view/ViewGroup.htmlhttp://developer.android.com/reference/android/view/ViewGroup.htmlhttp://developer.android.com/reference/android/view/View.html


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The menu items visible at the bottom of the screen at the press of the MENU key. It

supports a maximum of six menu items. These are the only menu items that support

icons and the only menu items that do notsupport checkboxes or radio buttons.

Expanded Menu

The vertical list of menu items exposed by the "More" menu item in the Icon Menu.

When the Icon Menu is full, the expanded menu is comprised of the sixth menu item

and the rest.

Context Menu

A floating list of menu items that appears when the user performs a long-press on a

View.

Submenu

A floating list of menu items that the user opens by pressing a menu item in the Options

Menu or a context menu. A submenu item cannot support a nested submenu.

Notifying the User

Topics

1. Creating Toast Notifications2. Creating Status Bar Notifications3. Creating Dialogs

Several types of situations may arise that require you to notify the user about an event that

occurs in your application. Some events require the user to respond and others do not. For

example:

When an event such as saving a file is complete, a small message should appear toconfirm that the save was successful.

If the application is running in the background and needs the user's attention, theapplication should create a notification that allows the user to respond at his or her

convenience.

If the application is performing work that the user must wait for (such as loading a file),the application should show a hovering progress wheel or bar.

Each of these notification tasks can be achieved using a different technique:

AToast Notification, for brief messages that come from the background.
http://developer.android.com/guide/topics/ui/notifiers/toasts.htmlhttp://developer.android.com/guide/topics/ui/notifiers/toasts.htmlhttp://developer.android.com/guide/topics/ui/notifiers/notifications.htmlhttp://developer.android.com/guide/topics/ui/notifiers/notifications.htmlhttp://developer.android.com/guide/topics/ui/dialogs.htmlhttp://developer.android.com/guide/topics/ui/dialogs.htmlhttp://developer.android.com/guide/topics/ui/notifiers/index.html#Toasthttp://developer.android.com/guide/topics/ui/notifiers/index.html#Toasthttp://developer.android.com/guide/topics/ui/notifiers/index.html#Toasthttp://developer.android.com/guide/topics/ui/notifiers/index.html#Toasthttp://developer.android.com/guide/topics/ui/dialogs.htmlhttp://developer.android.com/guide/topics/ui/notifiers/notifications.htmlhttp://developer.android.com/guide/topics/ui/notifiers/toasts.html


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AStatus Bar Notification, for persistent reminders that come from the background andrequest the user's response.

ADialog Notification, for Activity-related notifications.This document summarizes each of these techniques for notifying the user and includes linksto full documentation.

Toast

A toast notification is a message that pops up on the surface of the window. It only fills the

amount of space required for the message and the user's current activity remains visible and

interactive.

Status Bar Notification

A status bar notification adds an icon to the system's status bar (with an optional ticker-text

message) and an expanded message in the "Notifications" window. When the user selects the

expanded message

Activities

The building block of the user interface is the activity.

onCreate(BundlesavedInstanceState)

Called when the activity is starting

Content Providers

Content providers provide a level of abstraction for any data stored on the device that is

accessible by multiple applications.

Intents

Intents are system messages, running around the inside of the device, notifying applications of

various events, from hardware state changes, to incoming data, to application events.

The root element needs to declare the Android XML namespace:

xmlns:android=http://schemas.android.com/apk/res/android

android.preference

Provides classes that manage application preferences and implement the preferences UI.
http://developer.android.com/guide/topics/ui/notifiers/index.html#StatusBarhttp://developer.android.com/guide/topics/ui/notifiers/index.html#StatusBarhttp://developer.android.com/guide/topics/ui/notifiers/index.html#StatusBarhttp://developer.android.com/guide/topics/ui/notifiers/index.html#Dialoghttp://developer.android.com/guide/topics/ui/notifiers/index.html#Dialoghttp://developer.android.com/guide/topics/ui/notifiers/index.html#Dialoghttp://developer.android.com/reference/android/preference/PreferenceActivity.html#onCreate(android.os.Bundle)http://developer.android.com/reference/android/os/Bundle.htmlhttp://developer.android.com/reference/android/os/Bundle.htmlhttp://developer.android.com/reference/android/os/Bundle.htmlhttp://schemas.android.com/apk/res/androidhttp://schemas.android.com/apk/res/androidhttp://schemas.android.com/apk/res/androidhttp://developer.android.com/reference/android/os/Bundle.htmlhttp://developer.android.com/reference/android/preference/PreferenceActivity.html#onCreate(android.os.Bundle)http://developer.android.com/guide/topics/ui/notifiers/index.html#Dialoghttp://developer.android.com/guide/topics/ui/notifiers/index.html#StatusBar


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android.provider

Provides convenience classes to access the content providers supplied by Android.

A class for turning a byte stream into a character stream. Data read from the source inputstream is converted into characters by either a default or a provided character converter. The

default encoding is taken from the "file.encoding" system

property. InputStreamReader contains a buffer of bytes read from the source stream and

converts these into characters as needed. The buffer size is 8K.

Current Project: Global Online Mobile Share Trading System(GOM Trade)

1) Username2) Membership password3) Trading password4) Login5) Cancel6) Forgot password7) Change password8) Offline mode9) New user

Projects:

Drawing PanelDevelopment of an application using Android for drawing .In this we can able to draw

anything on the touch screen using gestures.Touch screens are a great way to interact

with applications on mobile devices. With a touch screen, users can easily tap, drag,

fling, or slide to quickly perform actions in their favourite applications. For app

developers, the Android framework makes it's easy to recognize simple actions, like a

swipe, but it has been more difficult to handle complicated gestures, sometimes

requiring developers to write a lot of code.You can use this application to create a set

of pre-defined gestures for your own application. It also serves as an example of how to

let the user defines own gestures in your applications.


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Language TranslatorThis Application is developed using Android. This program will let the user enter a

phrase in one language and ask Google to translate to a second language.It is extremely

easy to use and provides a great deal of real-world functionality. If youre travelling out

of the country, youll definitely want this app in your back pocket (forget the

dictionaries at home).Another great option built into this app is the ability to send a

translation via SMS and email. This is an incredibly useful and powerful feature which

can be used for many purposes. Note: some symbols might not be recognizable by your

recipients phone, so keep that in mind when sending a message in another language.

Gallery ViewsIn this we can view images in Grid view and when click any of the images we can see

that particular image in full size and the grid view also.Galleryis a layout widget used to

display items in a horizontally scrolling list and positions the current selection at the

centre of the view. In this, we can view a gallery of photos and then display a toast

message each time a gallery item is selected.

Sudoku GameAndroid Sudoku is an Android port of the classic Sudoku puzzle game.

The objective is to fill a 99 grid with digits so that each column, each row, and each of

the nine 33 sub-grids that compose the grid (also called "boxes", "blocks", "regions", or

"sub-squares") contains all of the digits from 1 to 9. The puzzle setter provides a

partially completed grid, which typically has a unique solution. This offers three

difficulty levels; hints for players are more interesting in this.
http://developer.android.com/reference/android/widget/Gallery.htmlhttp://developer.android.com/reference/android/widget/Gallery.htmlhttp://developer.android.com/reference/android/widget/Gallery.htmlhttp://developer.android.com/reference/android/widget/Gallery.html

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