5
How can I connect and disconnect with any device through Bluetooth communication and then exchange (send and/or receive) data?
4 answers
6
If you want a big, functional example, you can look at this my application on Github, Serialbtcontrol.
To Activitymain starts the Activitydevicelist in line 159, to list existing/pairable Bluetooth devices.
That one Activitydevicelist only serves to list the devices, and return to the Activitymain, which device was selected by the user. Have a look at the method onCreate, line 66, especially the BroadcastReceiver, who is responsible for receiving from Android the devices, and forward them to a ListView.
The method onItemClick, on line 175, that’s who ends the Activitydevicelist, returning the selected device to the Activitymain, that treats this term in the method activityFinished, on line 133. in activityFinished, line 141 creates the object responsible for the communication itself, which is an object of the class Btcommunicator.
The class Btcommunicator, in turn, is responsible for forwarding messages to the other device, using a OutputStream common Java, as shown in the sendMessage, on line 246.
To receive data from the other device, one should use InputStream from another Thread, as shown in the comment in line 139, which invokes the method receiveMessage, also commented on line 261.
This app works well, and has been tested. In fact, it is on Google Play.
This app of mine, in turn, is based on another open-source project called LEGO-MINDSTORMS-Minddroid, that can also serve you as reference, as it served me.
1
I didn’t test it, but it sounds like a good code of help: [Link]
Code:
package com.bluetooth;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Set;
import android.R.bool;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothClass;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.ParcelUuid;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
public class BluetoothDemo extends Activity {
/** Called when the activity is first created. */
ListView listViewPaired;
ListView listViewDetected;
ArrayList<String> arrayListpaired;
Button buttonSearch,buttonOn,buttonDesc,buttonOff;
ArrayAdapter<String> adapter,detectedAdapter;
static HandleSeacrh handleSeacrh;
BluetoothDevice bdDevice;
BluetoothClass bdClass;
ArrayList<BluetoothDevice> arrayListPairedBluetoothDevices;
private ButtonClicked clicked;
ListItemClickedonPaired listItemClickedonPaired;
BluetoothAdapter bluetoothAdapter = null;
ArrayList<BluetoothDevice> arrayListBluetoothDevices = null;
ListItemClicked listItemClicked;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listViewDetected = (ListView) findViewById(R.id.listViewDetected);
listViewPaired = (ListView) findViewById(R.id.listViewPaired);
buttonSearch = (Button) findViewById(R.id.buttonSearch);
buttonOn = (Button) findViewById(R.id.buttonOn);
buttonDesc = (Button) findViewById(R.id.buttonDesc);
buttonOff = (Button) findViewById(R.id.buttonOff);
arrayListpaired = new ArrayList<String>();
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
clicked = new ButtonClicked();
handleSeacrh = new HandleSeacrh();
arrayListPairedBluetoothDevices = new ArrayList<BluetoothDevice>();
/*
* the above declaration is just for getting the paired bluetooth devices;
* this helps in the removing the bond between paired devices.
*/
listItemClickedonPaired = new ListItemClickedonPaired();
arrayListBluetoothDevices = new ArrayList<BluetoothDevice>();
adapter= new ArrayAdapter<String>(BluetoothDemo.this, android.R.layout.simple_list_item_1, arrayListpaired);
detectedAdapter = new ArrayAdapter<String>(BluetoothDemo.this, android.R.layout.simple_list_item_single_choice);
listViewDetected.setAdapter(detectedAdapter);
listItemClicked = new ListItemClicked();
detectedAdapter.notifyDataSetChanged();
listViewPaired.setAdapter(adapter);
}
@Override
protected void onStart() {
// TODO Auto-generated method stub
super.onStart();
getPairedDevices();
buttonOn.setOnClickListener(clicked);
buttonSearch.setOnClickListener(clicked);
buttonDesc.setOnClickListener(clicked);
buttonOff.setOnClickListener(clicked);
listViewDetected.setOnItemClickListener(listItemClicked);
listViewPaired.setOnItemClickListener(listItemClickedonPaired);
}
private void getPairedDevices() {
Set<BluetoothDevice> pairedDevice = bluetoothAdapter.getBondedDevices();
if(pairedDevice.size()>0)
{
for(BluetoothDevice device : pairedDevice)
{
arrayListpaired.add(device.getName()+"\n"+device.getAddress());
arrayListPairedBluetoothDevices.add(device);
}
}
adapter.notifyDataSetChanged();
}
class ListItemClicked implements OnItemClickListener
{
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// TODO Auto-generated method stub
bdDevice = arrayListBluetoothDevices.get(position);
//bdClass = arrayListBluetoothDevices.get(position);
Log.i("Log", "The dvice : "+bdDevice.toString());
/*
* here below we can do pairing without calling the callthread(), we can directly call the
* connect(). but for the safer side we must usethe threading object.
*/
//callThread();
//connect(bdDevice);
Boolean isBonded = false;
try {
isBonded = createBond(bdDevice);
if(isBonded)
{
//arrayListpaired.add(bdDevice.getName()+"\n"+bdDevice.getAddress());
//adapter.notifyDataSetChanged();
getPairedDevices();
adapter.notifyDataSetChanged();
}
} catch (Exception e) {
e.printStackTrace();
}//connect(bdDevice);
Log.i("Log", "The bond is created: "+isBonded);
}
}
class ListItemClickedonPaired implements OnItemClickListener
{
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
bdDevice = arrayListPairedBluetoothDevices.get(position);
try {
Boolean removeBonding = removeBond(bdDevice);
if(removeBonding)
{
arrayListpaired.remove(position);
adapter.notifyDataSetChanged();
}
Log.i("Log", "Removed"+removeBonding);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
/*private void callThread() {
new Thread(){
public void run() {
Boolean isBonded = false;
try {
isBonded = createBond(bdDevice);
if(isBonded)
{
arrayListpaired.add(bdDevice.getName()+"\n"+bdDevice.getAddress());
adapter.notifyDataSetChanged();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}//connect(bdDevice);
Log.i("Log", "The bond is created: "+isBonded);
}
}.start();
}*/
private Boolean connect(BluetoothDevice bdDevice) {
Boolean bool = false;
try {
Log.i("Log", "service method is called ");
Class cl = Class.forName("android.bluetooth.BluetoothDevice");
Class[] par = {};
Method method = cl.getMethod("createBond", par);
Object[] args = {};
bool = (Boolean) method.invoke(bdDevice);//, args);// this invoke creates the detected devices paired.
//Log.i("Log", "This is: "+bool.booleanValue());
//Log.i("Log", "devicesss: "+bdDevice.getName());
} catch (Exception e) {
Log.i("Log", "Inside catch of serviceFromDevice Method");
e.printStackTrace();
}
return bool.booleanValue();
};
public boolean removeBond(BluetoothDevice btDevice)
throws Exception
{
Class btClass = Class.forName("android.bluetooth.BluetoothDevice");
Method removeBondMethod = btClass.getMethod("removeBond");
Boolean returnValue = (Boolean) removeBondMethod.invoke(btDevice);
return returnValue.booleanValue();
}
public boolean createBond(BluetoothDevice btDevice)
throws Exception
{
Class class1 = Class.forName("android.bluetooth.BluetoothDevice");
Method createBondMethod = class1.getMethod("createBond");
Boolean returnValue = (Boolean) createBondMethod.invoke(btDevice);
return returnValue.booleanValue();
}
class ButtonClicked implements OnClickListener
{
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.buttonOn:
onBluetooth();
break;
case R.id.buttonSearch:
arrayListBluetoothDevices.clear();
startSearching();
break;
case R.id.buttonDesc:
makeDiscoverable();
break;
case R.id.buttonOff:
offBluetooth();
break;
default:
break;
}
}
}
private BroadcastReceiver myReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
Message msg = Message.obtain();
String action = intent.getAction();
if(BluetoothDevice.ACTION_FOUND.equals(action)){
Toast.makeText(context, "ACTION_FOUND", Toast.LENGTH_SHORT).show();
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
try
{
//device.getClass().getMethod("setPairingConfirmation", boolean.class).invoke(device, true);
//device.getClass().getMethod("cancelPairingUserInput", boolean.class).invoke(device);
}
catch (Exception e) {
Log.i("Log", "Inside the exception: ");
e.printStackTrace();
}
if(arrayListBluetoothDevices.size()<1) // this checks if the size of bluetooth device is 0,then add the
{ // device to the arraylist.
detectedAdapter.add(device.getName()+"\n"+device.getAddress());
arrayListBluetoothDevices.add(device);
detectedAdapter.notifyDataSetChanged();
}
else
{
boolean flag = true; // flag to indicate that particular device is already in the arlist or not
for(int i = 0; i<arrayListBluetoothDevices.size();i++)
{
if(device.getAddress().equals(arrayListBluetoothDevices.get(i).getAddress()))
{
flag = false;
}
}
if(flag == true)
{
detectedAdapter.add(device.getName()+"\n"+device.getAddress());
arrayListBluetoothDevices.add(device);
detectedAdapter.notifyDataSetChanged();
}
}
}
}
};
private void startSearching() {
Log.i("Log", "in the start searching method");
IntentFilter intentFilter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
BluetoothDemo.this.registerReceiver(myReceiver, intentFilter);
bluetoothAdapter.startDiscovery();
}
private void onBluetooth() {
if(!bluetoothAdapter.isEnabled())
{
bluetoothAdapter.enable();
Log.i("Log", "Bluetooth is Enabled");
}
}
private void offBluetooth() {
if(bluetoothAdapter.isEnabled())
{
bluetoothAdapter.disable();
}
}
private void makeDiscoverable() {
Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
startActivity(discoverableIntent);
Log.i("Log", "Discoverable ");
}
class HandleSeacrh extends Handler
{
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 111:
break;
default:
break;
}
}
}
}
And in main.xml mail:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="@+id/buttonOn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="On"/>
<Button
android:id="@+id/buttonDesc"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Make Discoverable"/>
<Button
android:id="@+id/buttonSearch"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Search"/>
<Button
android:id="@+id/buttonOff"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Bluetooth Off"/>
<ListView
android:id="@+id/listViewPaired"
android:layout_width="match_parent"
android:layout_height="120dp">
</ListView>
<ListView
android:id="@+id/listViewDetected"
android:layout_width="match_parent"
android:layout_height="match_parent">
</ListView>
</LinearLayout>
Add this permission in the "menifest file":
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH" />
Other links that can help you:
How to connect with paired Bluetooth device programmatic in Android?
How to send file from Android device to other device through Bluetooth by code
1
Never used in android, however, bluetooth communication is not very different from a network socket, basically you establish a channel between the two devices and send/receive data through this channel. If you yourself will implement the two points of communication is relatively easy, however, if you are to communicate with a specific device you will need to know which protocol that device implements.
The documentation of android itself seems to me a good starting point, it includes some functional examples on how to identify and connect to a device.
http://developer.android.com/guide/topics/connectivity/bluetooth.html
-
i had already taken a look.. the documentation lacks some things q they do not explain clearly by going over some important things.. really wanted a complete and functional code..
0
You should use the Android SDK Bluetooth API, with the @Perrywerneck link and this Bluetoothsocket documentation I think will solve your problem.
http://developer.android.com/reference/android/bluetooth/BluetoothSocket.html
Complete documentation of the SDK Bluetooth API:
http://developer.android.com/reference/android/bluetooth/package-summary.html
If you already want an example code to orient yourself, follow below:
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i had already taken a look.. the documentation lacks some things q they do not explain clearly by going over some important things.. really wanted a complete and functional code.
-
1
What exactly would be your question? What is missing for you to function? How far has it come?
Browser other questions tagged android connection mobile
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vlw dude. I’ll still take a look at your code is probably what I was looking for... I’ll give +1 in your post and until tomorrow I’ll be giving the points to you.
– Pedro Rangel
@Pedrorangel No problem! Anything, just ask! :)
– carlosrafaelgn