Android

Accessories

Sathish. R

Roadmap

Bluetooth

Wi-Fi

Sensors Motion Sensors Position Sensors

Environment Sensors

Send/ Receive SMS

Shared Preference

Hands-on

Android

Accessories

Session 3

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Bluetooth o Which allows a device to wirelessly exchange

data with other Bluetooth devices.

o The application framework provides access

to the Bluetooth functionality through the

Android Bluetooth APIs.

o Bluetooth APIs let applications wirelessly

connect to other Bluetooth devices.

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Bluetooth Cont. o Scan for other Bluetooth devices

o Query the local Bluetooth adapter for paired Bluetooth devices

o Establish RFCOMM channels

o Connect to other devices through service discovery

o Transfer data to and from other devices

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Bluetooth Cont. All of the Bluetooth APIs are available in the android. Bluetooth package.

The four major tasks necessary to communicate using Bluetooth.

setting up Bluetooth, finding devices that are either paired or available in

the local area, connecting devices &

transferring data between devices.

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Bluetooth Cont.

The classes and interfaces you will need to

create Bluetooth connections:

Bluetooth Adapter.

Bluetooth Device.

Bluetooth Socket.

Bluetooth Server Socket.

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Bluetooth Permissions.

o We must declare the Bluetooth

permission BLUETOOTH.

o To initiate device discovery or manipulate

Bluetooth settings, we must also declare

the BLUETOOTH_ADMIN permission.

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Setting Up Bluetooth

Verify that Bluetooth is supported on the

device.

If Bluetooth is not supported, then disable

any Bluetooth features.

o Get the BluetoothAdapter.

o Enable Bluetooth.

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Setting Up Bluetooth

Get Bluetooth Adapter:

The BluetoothAdapter is required for any

and all Bluetooth activity.

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Setting Up Bluetooth Enable Bluetooth.

o Ensure that Bluetooth is enabled.

o Call isEnabled() to check whether

Bluetooth is currently enable. If this

method returns false, then Bluetooth is

disabled.

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Finding Devices o Find remote Bluetooth devices either through device

discovery or by querying the list of paired (bonded) devices.

o Device discovery is a scanning procedure that searches the local area for Bluetooth enabled devices.

o A Bluetooth device within the local area will respond to a discovery request only if it is currently enabled to be discoverable

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Querying paired devices

o Before performing device discovery, its

worth querying the set of paired devices.

o call getBondedDevices().

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Discovering devices o simply call startDiscovery().

o The method will immediately return with a

Boolean indicating whether discovery has

successfully started.

o Involves an inquiry scan of about 12 seconds,

followed by a page scan of each found

device to retrieve its Bluetooth name.

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Discovering devices o Register a Broadcast Receiver for

the ACTION_FOUND Intent in order to receive

information about each device discovered.

o This Intent carries the extra

fields EXTRA_DEVICE and EXTRA_CLASS,

containing a BluetoothDevice and a

BluetoothClass.

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Discovering devices

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Connecting Devices o To create a connection between two

devices, implement both the server-side and client-side mechanisms.

o If the two devices have not been previously paired, then the Android framework will automatically show a pairing request notification or dialog to the user during the connection procedure.

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Connecting as a server o One must act as a server by holding an

open BluetoothServerSocket.

o The server socket is to listen for incoming connection requests.

Get a BluetoothServerSocket by calling the listenUsingRfcommWithServiceRecord(String, UUID).

Start listening for connection requests by calling accept().

Unless you want to accept additional connections, call close().

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Connecting as a client o To initiate a connection with a remote

device , obtain the remote device.

o Using the Bluetooth Device, get a BluetoothSocket by calling createRfcommSocketToServiceRecord (UUID).

Note : The UUID passed here must match the UUID used by the server device when it opened its BluetoothServerSocket

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Connecting as a client o Initiate the connection by calling connect().

o We should always ensure that the device is

not performing device discovery when you

call connect().

o If discovery is in progress, then the

connection attempt will be significantly

slowed and is more likely to fail.

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Managing a Connection

Once Both Devices are connected

Get the InputStream and OutputStream that

handle transmissions through the socket,

Read and write data to the streams.

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Wi-Fi

o The Primary API for managing all aspects

of Wi-Fi connectivity.

o It deals with several categories of items:

The list of configured networks.

The currently active Wi-Fi network.

Results of access point scans.

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Turn On/Off Wi-Fi

o Need to use WiFiManager class.

o Create an Object of WiFiManager class to

get the services of Wi-Fi.

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Permission in Manifest

o When performing Wi-Fi specific

operations, we must declare permissions

in manifest file

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Sensors o Most Android-powered devices

have built-in sensors that measure motion, orientation, and various environmental conditions.

o These sensors are capable of providing raw data with high precision and accuracy, and are useful

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Sensors The Android platform supports three broad categories of sensors:

Motion sensors (accelerometers, gravity sensors, gyroscopes)

Environmental sensors (pressure, illumination, and humidity)

Position sensors ( orientation sensors and magnetometers)

We can access sensors available on the device and acquire raw

sensor data by using the Android sensor framework.

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Sensors We can use the sensor framework to do the following:

Determine which sensors are available on a device.

Determine an individual sensor's capabilities, such as its maximum range, manufacturer, power requirements, and resolution.

Acquire raw sensor data and define the minimum rate at which you acquire sensor data.

Register and unregister sensor event listeners that monitor sensor changes.

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Identifying Sensors and Sensor

Capabilities

o The Android sensor framework provides

several methods to determine at runtime

which sensors are on a device.

o To identify the sensors that are on a

device you first need to get a reference

to the sensor service.

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Access Sensors:

o We can get a listing of every sensor on a

device by calling

the getSensorList() method

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Monitoring Sensor Events

To monitor raw sensor data you need to

implement two callback methods of

SensorEventListener interface.

onAccuracyChanged() and

onSensorChanged().

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Send SMS

o Add permission in manifest.xml

o To send sms we need sms manager.

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Send SMS The sendTextMessages() method takes five arguments:

o destinationAddress

o scAddress

o Content of the SMS message

o sentIntent

o deliveryIntent

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Receive SMS o Declare Broadcast receiver in Android

Manifest.xml

o Give read SMS permission in AndroidManifest

o Get the object of SmsManager to find out received sms details

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Receive SMS

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BroadcastReceiver receiver = new BroadcastReceiver() {

public void onReceive(Context c, Intent in) {

if(in.getAction().equals(RECEIVED_ACTION)) {

Bundle bundle = in.getExtras();

if(bundle!=null) {

Object[] pdus = (Object[])bundle.get(“pdus”);

SmsMessage[] msgs = new SmsMessage[pdus.length];

for(int i = 0; i<pdus.length; i++) {

msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);

}

// reply();

}

}

}};

Shared Preferences o Android provides several options to save

persistent application data

o Store private primitive data in key-value pairs.

o Application shared preferences allows you to save and retrieve key, value pair data.

o Boolean, float, int, long and string.

o These data will persist even app is killed

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Shared Preferences

o Application shared preferences can be

fetched using getSharedPreferences()

method.

o We need an editor to edit and save the

changes in shared preferences.

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Shared Preferences Storing Data:

o You can save data into shared

preferences using editor.

o Call editor. Commit() in order to save

changes to shared preferences.

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Shared Preferences

Retrieving Data

o Data can be retrieved from saved

preferences by calling getString() (For

string) method.

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Shared Preferences Clearing / Deleting Data

o To delete that particular value, call

remove(“key_name”).

o If we want to delete all the data,

call clear().

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