Bluetooth in J2ME :- Simple chat application pot

http://delhidaredevilzgalary.blogspot.com/2011/08/bluetooth-in-j2me-simple-chat.html Bluetooth in J2ME :- Simple chat application Posted by vaibhav In previous tutorial , we learned about Bluetooth Device Discovery. In this tutorial we will learn ,how to make simple bluetooth connection .In this we will implement the code in which approval for connection is not required by the sender. Reciever automatically recieves the sent text. Here is the code for the Bluetooth Chat:-(2 .java files ) Client.java:- import java.io.*; import javax.bluetooth.*; import javax.microedition.io.Connector; import javax.microedition.io.StreamConnection; import javax.microedition.lcdui.*; import javax.microedition.midlet.*; /* * @author Vaibhav */ public class Client extends MIDlet implements CommandListener,DiscoveryListener,Runnable { private Display display; public List devicelist; private final List deviceList; public DiscoveryAgent agent; public String deviceName,address; private Command Refresh,connect,end,Exit; private String s,url; private Alert dialog1; private StreamConnection conn; private Server b; private DataOutputStream dos; private String[][] array[][] ; Thread t; public Form ChatForm = new Form("chat window"); private Command send,exit; private TextField textfield; private String sendmsg; public Client() { deviceList = new List("List of Devices",List.IMPLICIT); Exit= new Command("Exit",Command.EXIT, 0); connect = new Command("connect",Command.SCREEN, 1); Refresh = new Command("Refresh",Command.SCREEN, 1); end = new Command("End",Command.EXIT, 1); deviceList.addCommand(Exit); deviceList.addCommand(connect); deviceList.addCommand(Refresh); deviceList.setCommandListener(this); Display.getDisplay(this).setCurrent(deviceList); t = new Thread(this); } public void startApp() throws MIDletStateChangeException { try { b=new Server(this); getChatForm(); deviceList.deleteAll(); LocalDevice local = LocalDevice.getLocalDevice(); address = local.getBluetoothAddress(); agent = local.getDiscoveryAgent(); } catch (BluetoothStateException ex) { throw new MIDletStateChangeException("Unable to retrieve local Bluetooth device."); } } public void pauseApp() { } public void clear() throws IOException { b.destroy(); } public void destroyApp(boolean unconditional) throws MIDletStateChangeException{ notifyDestroyed(); } public void commandAction(Command c, Displayable d) { if(c==Exit) { try { dos.writeUTF("eof"); } catch (IOException ex) { ex.printStackTrace(); } notifyDestroyed(); } if(c==Refresh){ try { try { agent.startInquiry(DiscoveryAgent.GIAC, this); dialog1 = new Alert("Searching","Please Wait ,Searching devices",null,AlertType.INFO); dialog1.setTimeout(1000); Display.getDisplay(this).setCurrent(dialog1); } catch (BluetoothStateException e) { throw new MIDletStateChangeException("Unable to start the inquiry"); } } catch (MIDletStateChangeException ex) { ex.printStackTrace(); } } if(c==connect){ Display.getDisplay(this).setCurrent(ChatForm); s= deviceList.getString(deviceList.getSelectedIndex()); url = "btspp://"+ s + ":" + "1" ; System.out.println(url); t.start(); } if(c==send){ sendmsg = textfield.getString() ; textfield.setString(""); this.ChatForm.append("\n"+"ME: "+sendmsg); try { dos.writeUTF(address+sendmsg); } catch (IOException ex) { ex.printStackTrace(); } } } public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) { try { String deviceaddress = btDevice.getBluetoothAddress(); String address = btDevice.getFriendlyName(true); deviceList.insert(0, deviceaddress , null); } catch (IOException ex) { ex.printStackTrace(); } } public void servicesDiscovered(int transID, ServiceRecord[] servRecord) { } public void serviceSearchCompleted(int transID, int respCode) { } public void inquiryCompleted(int discType) { Alert dialog = null; if (discType != DiscoveryListener.INQUIRY_COMPLETED) { dialog = new Alert("Bluetooth Error","The inquiry failed to complete normally",null, AlertType.ERROR); } else { dialog = new Alert("Inquiry Completed","The inquiry completed normally", null,AlertType.INFO); } dialog.setTimeout(500); Display.getDisplay(this).setCurrent(dialog); } public void run() { try { conn = (StreamConnection) Connector.open(url); dos = conn.openDataOutputStream(); } catch (Exception ex) { System.out.println("here"); ex.printStackTrace(); } } public void setText(String s) { this.ChatForm.append("\n"+"Friend: "+s); } public void getChatForm() { textfield = new TextField("type text ","",50,TextField.ANY); exit = new Command ("Exit", Command.EXIT,1); send = new Command ("send",Command.OK,1); ChatForm.append(textfield); ChatForm.append(" "); ChatForm.addCommand(exit); ChatForm.addCommand(send); ChatForm.setCommandListener(this); } void setUp(String url1) { try{ url = "btspp://"+ url1 + ":" + "1" ; t.start(); }catch(Exception e){ e.printStackTrace(); } } } Server.java:- import java.io.*; import javax.bluetooth.*; import javax.microedition.io.*; import javax.microedition.lcdui.Display; /** * @author Vaibhav */ public class Server implements Runnable { public DataInputStream dis; private StreamConnection con; public boolean listening = false; private Client Client; StreamConnectionNotifier notifier = null ; String msg,msg1,msg2; int count; public Server(Client Client) { this.Client = Client; count=0; try{ Thread t = new Thread(this); t.start(); } catch(Exception e) {} } public void run() { try { // retrieve the local Bluetooth device object LocalDevice localDevice = LocalDevice.getLocalDevice(); // retrieve the Bluetooth address of the local device String address = localDevice.getBluetoothAddress(); // retrieve the name of the local Bluetooth device String deviceName = localDevice.getFriendlyName(); System.out.println(address+" "+deviceName); DiscoveryAgent agent =localDevice.getDiscoveryAgent(); localDevice.setDiscoverable(DiscoveryAgent.GIAC); UUID uuid = new UUID(0x0009); String url = "btspp://localhost:" + uuid + ";name=" + deviceName + ";" + "authenticate=true" ; notifier = (StreamConnectionNotifier) Connector.open(url); con =notifier.acceptAndOpen(); dis =con.openDataInputStream(); listening = true; setChat(); } catch (Exception ex) { ex.printStackTrace(); } } public void destroy() throws IOException { notifier.close(); listening = false; } public void setChat() { try{ while(listening) { msg = dis.readUTF(); msg1=msg.substring(0,12); msg2=msg.substring(12); if(count==0) { Client.setUp(msg1); } count=1; try{ if(!msg2.equals("eof")){ Display.getDisplay(Client).setCurrent(Client.ChatForm); System.out.println(msg2); Client.setText(msg2); } else listening=false; } catch(Exception e) { e.printStackTrace(); } } } catch(Exception ex) { ex.printStackTrace(); } } } Now first we will go through the Midlet Client.java As you can see ,it is almost similar to the previous tutorial code ,device discovery. When constructor client runs ,it initialises the Displayable item. StartApp() meanwhile creates the instance of Server class and calls its constructor. It also calls getChatForm() which defined the display of chatform as you can see in the getChatForm function code. Rest of the command is same as it was in device discovery. Now when refresh button is pressed, then the mobile searches for bletooth device through startInquiry(0 as explained in previous tutorial. After we have got a list of devices and then we press connect on selected address then the commandaction of connect comes into play. It checks for the selected device , gets its address and creates a URL as visible in following statements. s= deviceList.getString(deviceList.getSelectedIndex()); url = "btspp://"+ s + ":" + "1" ; Then the Thread is started. The run function is excecuted , in which conn = (StreamConnection) Connector.open(url); dos = conn.openDataOutputStream(); commands creates a stream connection to the url created in connect command. Then a dataoutput stream is opened to send data. Now when send command is given , sendmsg = textfield.getString() ; gets the string entered. This append the sent message to sender's screen. this.ChatForm.append("\n"+"ME: "+sendmsg); Then this command sends the data and address of the sending mobile through outputstreamconnection. dos.writeUTF(address+sendmsg); This concludes client side coding. Now in server class,as soon as its instance is created by client ,its constructor runs. this.Client = Client; Above command hepls the class to locate its parent class. Then it starts the thread. The run function on server is executed. This statement retrieves the local Bluetooth device object LocalDevice localDevice = LocalDevice.getLocalDevice() ; Then it retrieve the Bluetooth address of the local device String address = localDevice.getBluetoothAddress(); This retrieve the name of the local Bluetooth device String deviceName = localDevice.getFriendlyName(); This creates a discoveryagent. DiscoveryAgent agent =localDevice.getDiscoveryAgent(); This sets the device as discoverable.Check for other options available for hiding the device. localDevice.setDiscoverable(DiscoveryAgent.GIAC); UUID uuid = new UUID(0x0009); String url = "btspp://localhost:" + uuid + ";name=" + deviceName + ";" + "authenticate=true" ; above 2 statements prepares the Connection URL. This statement creates the connection notifier. notifier = (StreamConnectionNotifier) Connector.open(url); Now the essence of our coding was that it didn't required approval .here is the piece of code which decides it. con =notifier.acceptAndOpen(); It automatically accepts incoming connection and opens stream. dis =con.openDataInputStream(); Then setchat function is executed. msg = dis.readUTF(); msg1=msg.substring(0,12); msg2=msg.substring(12); Above coding is done to seperate address and the text so that address can be used to connect back to the sender and data is displayed on chatform (however setText function of client is used for this purpose.) However when count is 0 ,it calls setUp function. This is done when the reciever recieves data for the first time .This is done so that it can connect back to the sender to reply. However when reciever sends back 2nd time ,the count increses to more than 0 and it skips this part. Finally setUp function of client just prepares the connection URL for server to connect back. This concludes our tutorial . In next tutorial we'll learn request/response connection in which reciever can accept /reject the connection. http://delhidaredevilzgalary.blogspot.com/2011/07/bluetooth-in-j2me-bluetooth-device.html Bluetooth in J2ME : Bluetooth Device Discovery Posted by vaibhav In this tutorial we will learn about Mobile Bluetooth and its application using J2ME. First of all , for all those who give more importance to underlying protocols , i found a beautiful explaination on this site:- http://developers.sun.com/mobility/midp/articles/bluetooth1 Now after you know basic protocol structure (However its not mandatory to create application) , we can start with the modules we have to follow. In Bluetooth programming wehave following jobs in our hand:- • Device Discovery • Request/Response for Connection • Sending Data • Recieving Data In this particular tutorial we'll be limiting ourselves to device discovery only. Rest we'll cover in subsequent posts. First of all we should know that we will use(rather the only one available) the java API JSR82. For information regarding device compatibility , minimum requirements , requirements for application development and lots more you can go through this link:- http://developers.sun.com/mobility/midp/articles/bluetooth2 Now let us first go through the code :- import java.io.IOException; import javax.bluetooth.*; import javax.bluetooth.DiscoveryListener; import javax.microedition.lcdui.*; import javax.microedition.midlet.*; /** * @author Vaibhav */ public class discover_device extends MIDlet implements CommandListener,DiscoveryListener { private final List deviceList; private final Command Exit,Refresh; private String deviceName; private DiscoveryAgent agent; private Alert dialog; public discover_device() { deviceList = new List("List of Devices",List.IMPLICIT); Exit= new Command("Exit",Command.EXIT, 0); Refresh = new Command("Refresh",Command.SCREEN, 1); deviceList.addCommand(Exit); deviceList.addCommand(Refresh); deviceList.setCommandListener(this); Display.getDisplay(this).setCurrent(deviceList); } public void startApp() { try { deviceList.deleteAll(); LocalDevice local = LocalDevice.getLocalDevice(); local.setDiscoverable(DiscoveryAgent.GIAC); deviceName = local.getFriendlyName(); agent = local.getDiscoveryAgent(); } catch (BluetoothStateException ex) { ex.printStackTrace(); } try { agent.startInquiry(DiscoveryAgent.GIAC, this); } catch (BluetoothStateException ex) { ex.printStackTrace(); } } public void pauseApp() { } public void destroyApp(boolean unconditional) { } public void commandAction(Command c, Displayable d) { if(c==Exit) { this.destroyApp(true); notifyDestroyed(); } if(c==Refresh){ this.startApp(); } } [...]... searching for devices (being a critical command ,its being put into try catch) Then after inquiry is complete ,then inquiryCompleted() is executed ,which displays whether inquiry is completed successfully or not Finally deviceDiscovered() comes to action setting all the display of device discovered on the list You can choose between name or address of device to be displayed on list by choosing between these... UnsupportedOperationException("Not supported yet."); } public void inquiryCompleted(int discType) { Alert dialog = null; if (discType != DiscoveryListener.INQUIRY_COMPLETED) { dialog = new Alert( "Bluetooth Error","The inquiry failed to complete normally",null, AlertType.ERROR); } else { dialog = new Alert("Inquiry Completed","The inquiry completed normally", null,AlertType.INFO); } dialog.setTimeout(500); Display.getDisplay(this).setCurrent(dialog);... String deviceaddress = null; try { deviceaddress = btDevice.getBluetoothAddress();//btDevice.getFriendlyName(true); } catch (Exception ex) { ex.printStackTrace(); } deviceList.insert(0, deviceaddress , null); } public void servicesDiscovered(int transID, ServiceRecord[] servRecord) { throw new UnsupportedOperationException("Not supported yet."); } public void serviceSearchCompleted(int transID, int... However using local.setDiscoverable(DiscoveryAgent.NOT_DISCOVERABLE); we can hide our bluetooth (not visible to others but others are visible to us) deviceName = local.getFriendlyName(); This gives us the device name agent = local.getDiscoveryAgent(); This sets a discovery agent for bluetooth enquiry agent.startInquiry(DiscoveryAgent.GIAC, this); This is the main statement which starts searching for... be displaying the searched device (name or address) and on that same list we will add the command to search and exit This will be our first display item on starting the application Then the control goes to startApp() function The very first command deviceList.deleteAll(); deletes all devices from previous search LocalDevice local = LocalDevice.getLocalDevice(); This command gets the local bluetooth. .. of device to be displayed on list by choosing between these tho statements deviceaddress = btDevice.getBluetoothAddress(); deviceaddress= btDevice.getFriendlyName(true); The other one is commented in code This Completes out tutorial on Bluetooth device discovery We'll learn about connection set-up in subsequent part . http://delhidaredevilzgalary.blogspot.com/2011/08 /bluetooth- in- j2me- simple- chat. html Bluetooth in J2ME :- Simple chat application Posted by vaibhav In previous tutorial , we learned about Bluetooth Device Discovery. In this. request/response connection in which reciever can accept /reject the connection. http://delhidaredevilzgalary.blogspot.com/2011/07 /bluetooth- in- j2me -bluetooth- device.html Bluetooth in J2ME : Bluetooth Device. modules we have to follow. In Bluetooth programming wehave following jobs in our hand:- • Device Discovery • Request/Response for Connection • Sending Data • Recieving Data In this particular tutorial