Android Software Engineer

AOSP stands for Android Open-source project that maintains Android software and keep track of the new versions. It can be used for any purpose including the devices that are not compatible with other devices. It is related to the Android Compatibility Program as it defines the implementation of Android that is compatible with the third party apps.

AIDL supports following data types:

★ String

★ List

★ Map

★ CharSequence

★ All native Java data types like int,long, char and Boolean

★ It is Android's virtual machine.

★ It is an interpreter-only virtual machine which executes files in Dalvik Executable (.dex) format. This format is optimized for efficient storage and memory-mappable execution.

When we create android application the following folders are created in the package explorer in eclipse which are as follows:

★ src

★ gen

★ assets

★ bin

★ res

Activity provides the user interface. When you create an android application in eclipse through the wizard it asks you the name of the activity. Default name is MainActivity. You can provide any name according to the need. Basically it is a class (MainActivity) that is inherited automatically from Activity class. Mostly, applications have oneor more activities; and the main purpose of an activity is to interact with the user. Activity goes through a numberof stages, known as an activity's life cycle.

Android provides many options for storage of persistent data. It provides the solution according to your need. The storages which have been provided in Android are as follows:-

Shared Preferences: Store private primitive data in key-value pairs

Internal Storage: Store private data on the device memory.

External Storage: Store public data on the shared external storage.

SQLite Databases: Store structured data in a private database.

Network Connection: Store data on the web with your own network server.

Android application architecture allows the simplification and reuse of any application. It provides a better way to publish the capabilities of the application so that any other application can make good use of those capabilities. This architecture includes the following components:

Intent: perform some operation on some activity and service

Resource Externalization - such as strings and graphics

Notification signaling users - light, sound, icon etc.

Content Providers - sharing of data between various applications

There are 4 dialog boxes which have been supported by Android. These are as follows:

AlertDialog: it supports 0 to 3 buttons with a list of selectable elements that includes check boxes and radio buttons.

-ProgressDialog: it displays the progress of any dialog or application. It is an extension of AlertDialog and supports adding buttons.

-DatePickerDialog: it is used to give provision to the user to select the date

- TimePickerDialog: it is used to give provision to the user to select the time

APK termed as Application package file is a format that is used to distribute and install the application software for android, and middleware on the android operating system. To make an APK file, first android is compiled and then all of its parts are grouped in one file termed as package. The package consists of the entire program's code (.dex files), resources, manifest file etc. The file is saved with .apk extension.

Intent is basically an abstract description of an operation that has to be performed for communication. Sticky Intent is also a type of intent which allows the communication between a function and a service. For example: sendStickyBroadcast() performs send Broadcast(Intent) which stays even after the broadcast is complete. It helps in retrieving the data quickly. The message ACTION_BATTERY_CHANGED of an operating system is an example of it.

Android uses Google translator to translate data from one language into another language using XAMPP. XAMPP is used to transmit the data. The steps which have to be followed are: Type the message in your language, go to the language setting, a list will be displayed there, select the language from the list to convert your text.

Android Application Architecture has the following components:

Services - like Network Operation

Intent - To perform inter-communication between activities or services

Resource Externalization - such as strings and graphics

Notification signaling users - light, sound, icon, notification, dialog etc.

Content Providers - They share data between applications

Imagine a situation that you are in a country where no one understands the language you speak and you can not read or write. However, you have mobile phone with you.

With a mobile phone with android, the Google translator translates the data of one language into another language by using XMPP to transmit data. You can type the message in English and select the language which is understood by the citizens of the country in order to reach the message to the citizens.

Android is useful because:

It is simple and powerful SDK

Licensing, Distribution or Development fee is not required

Easy to Import third party Java library

Supporting platforms are - Linux, Mac Os, Windows.

Android supports 4 dialog boxes:

AlertDialog : An alert dialog box supports 0 to 3 buttons and a list of selectable elements, including check boxes and radio buttons. Among the other dialog boxes, the most suggested dialog box is the alert dialog box.

ProgressDialog: This dialog box displays a progress wheel or a progress bar. It is an extension of AlertDialog and supports adding buttons.

DatePickerDialog: This dialog box is used for selecting a date by the user.

TimePickerDialog: This dialog box is used for selecting time by the user.

The following are the advantages of Android:

The customer will be benefited from wide range of mobile applications to choose, since the monopoly of wireless carriers like AT&T and Orange will be broken by Google Android.

Features like weather details, live RSS feeds, opening screen, icon on the opening screen can be customized

Innovative products like the location-aware services, location of a nearby convenience store etc., are some of the additive facilities in Android.

The following are the exceptions that are supported by Android

InflateException : When an error conditions are occurred, this exception is thrown

Surface.OutOfResourceException: When a surface is not created or resized, this exception is thrown

SurfaceHolder.BadSurfaceTypeException: This exception is thrown from the lockCanvas() method, when invoked on a Surface whose is SURFACE_TYPE_PUSH_BUFFERS

WindowManager.BadTokenException: This exception is thrown at the time of trying to add view an invalid WindowManager.LayoutParamstoken.

Specify android id, layout height and width as depicted in the following example.

<ListView android:id="@+id/ListView01" android:layout_height="wrap_content" android:layout_width="fill_parent"></ListView>

Components can be reused and replaced by the application framework.

Optimized DVM for mobile devices

SQLite enables to store the data in a structured manner.

Supports GSM telephone and Bluetooth, WiFi, 3G and EDGE technologies

The development is a combination of a device emulator, debugging tools, memory profiling and plug-in for Eclipse IDE.