Android booting sequece and setup and debugging

Android SDK introduction

Android SDK library distribution according to functionality

Activity, Services and Broadcast

Receivers

Activities The entry class into Android application, responsible for loading the first screen and take user inputs

-onCreate()

-onDestroy();

-onPause();

-onStart();

Services The class used to create programs that run in background, and have no UI

Broadcast receiver The android component responsible to receive responses from system wide processes and send the event notification to the registered processes

Views

View Responsible for the UI in the application.

A view is put on a layout and then as per programming directives a layout is laid

Intents, Adapters, AlertDialogue and Notifications

Intents - Intents are used as a message-passing mechanism that works both within application, and between applications. Intents can be used to:

Adapters - Adapters are bridging classes that bind data to Views used in the user interface. And load dynamic data in the UI

AlertDialouge To show the user the Alert and seek any response, and then perform any action on it

Notification - notify the user on any

event in the notification bar

.

Content Providers and Data storage

Content Providers - Content providers are interfaces to store and retrieve data and make it accessible to all applications. They're the only way to share data across applications

Data Storage - Android provides several options for you to save persistent application data. The solution you choose depends on your specific needs

Data storage methods in brief

Shared preferences - The SharedPreferences class provides a general framework that allows you to save and retrieve persistent key-value pairs of primitive data types

getSharedPreferences(), getPreferences() use these methods to obtain multiple or single preferences for the application respectively.

Edit() or putBoolean(), putString() etc use the former method to use SharedPreference.Editor, and later methods to directly specify and enter the data

Internal Storage - We can save files directly on the device's internal storage, by using the FileStream class and its methods write() and read() etc.

External Storage The external storage device in Android mobiles is the SD card. We can save and retrieve data on SD card using some of the methods

SQLite Database

Android provides full support for SQLite databases. Any databases you create will be accessible by name to any class in the application, but not outside the application.

To create a new SQLite database is to create a subclass of SQLiteOpenHelper and override the onCreate() method, in which you can execute a SQLite command to create tables in the database.

getWritableDatabase() and getReadableDatabase()

To write and read from database, their return type is SQLiteDatabase class that provides methods for database operations.

SQLiteDatabase query() methods to execute queries, these methods takes various parameters, for various quires.

Cursor Its the return type of any SQLite query and the mechanism with which you can navigate results from a database query and read rows and columns.

Maps and GeoCoding

Important classes related to GPS capabilities in Android

getLastKnownLocation(provider);

Geocoder(Contextcontext,Localelocale)

Geocoder(Contextcontext)

Android App Widgets

App Widgets are miniature application views that can be embedded in other applications (such as the Home screen) and receive periodic updates.

AppWidgetProviderInfo object Describes the metadata for an App Widget.

AppWidgetProvider class implementation Defines the basic methods that allow you to programmatically interface with the App Widget, based on broadcast events.

onUpdate()

onDeleted(Context, int[])

onEnabled(Context)

onReceive(Context, Intent)

View class to draw the widget layout

Multimedia content

Multimedia playback in Android is handled by the MediaPlayer class. You can play media stored in application resources, local files, Content Providers, or streamed from a network URL

create(appContext, R.raw.my_audio);

setDataSource("/sdcard/test2.3gp");

prepare();

For playing Video, we have to use a VideoView to act a surface to display the video

MediaRecorder class and associated methods are used for recording video

Using Intents Actions we can use camera and audio recording features

Telephony and SMS

Provides APIs for monitoring the basic phone information, such as the network type and connection state, plus utilities for manipulating phone number strings.

SmsManager - Manages SMS operations such as sending data, text, and pdu SMS messages. Get this object by calling the static method SmsManager.getDefault()

sendTextMessage() to send text SMS

Bluetooth and WiFi

Using the Bluetooth APIs, an Android application can perform the following:

BluetoothAdapter - The BluetoothAdapter is the entry-point for all Bluetooth interaction.

BluetoothDevice - Represents a remote Bluetooth device.

BluetoothSocket - This is the connection point that allows an application to exchange data with another Bluetooth device via InputStream and OutputStream.

BluetoothServerSocket - - Represents an open server socket that listens for incoming requests (similar to a TCP ServerSocket).

The WifiManager represents the Android Wi-Fi Connectivity Service. It can be used to configure Wi-Fi network connections, manage the current Wi-Fi connection, scan for access points, and monitor changes in Wi-Fi connectivity

Android Booting Sequence

Stages In Booting of Android OS from power on

Stage 1 : Power on and boot ROM code execution

Stage 2: The boot loader loading

Stage 3: Starting of Linux kernel

Stage 4: The init process

Stage 5: Zygote and Dalvik

Stage 6: The system server initiation

Android Booting Sequence Stage 1

Power on and boot ROM code execution

Android Booting Sequence Stage 2

The boot loader loading

Android Booting Sequence Stage 3

Starting of Linux kernel

It will set up everything that is needed for the system to run. Initialize interrupt controllers, set up memory protections, caches and scheduling.