Android Bluetooth Learning

Learning Route

1 Bluetooth permissions

<android:name= "Android.permission.BLUETOOTH"/><   android:name= "Android.permission.BLUETOOTH_ADMIN"/><   android:name= "Android.permission.ACCESS_COARSE_LOCATION"/>//Android 6.0 version requires location permissions 

2 Turn on Bluetooth

public void OnOpen (View v) {        bluetoothadapter = Bluetoothadapter.getdefaultadapter ();//Get the Bluetooth adapter        if (! Bluetoothadapter.isenabled ()) {                     //If Bluetooth is off, open            bluetoothadapter.enable ();            ShowMessage ("Open bluetooth");        } else {            ShowMessage ("Bluetooth is already open");        }    }

3 scan around Bluetooth (get paired Bluetooth)

Scanning the surrounding Bluetooth needs to define a broadcast receiver

PrivateBroadcastreceiver mreceiver=NewBroadcastreceiver () {@Override Public voidOnReceive (Context context, Intent Intent) {String action=intent.getaction (); LOG.I ("Boye", action); if(Action.equals (Bluetoothdevice.action_found)) {Bluetoothdevice device=Intent.getparcelableextra (Bluetoothdevice.extra_device); Get the device you are currently scanning toif(Device.getbondstate () ==bluetoothdevice.bond_bonded) {//Show paired DevicesTextview.append ("\ n" +device.getname () + "==>" +device.getaddress () + "\ n"); Toast.maketext (Context,"Found paired device:" +device.getname (), Toast.length_long). Show (); } Else if(Device.getbondstate ()! =bluetoothdevice.bond_bonded) {Textview3.append ("\ n" +device.getname () + "==>" +device.getaddress () + "\ n"); Toast.maketext (Context,"Found an unpaired device:" +device.getname (), Toast.length_long). Show (); }            } Else if(Action.equals (bluetoothadapter.action_discovery_finished)) {Textview2.settext ("Search Complete ..."); }        }    };

Broadcast filters

Intentfilter filter=New  intentfilter (bluetoothdevice.action_found);                  Filter out found Registerreceiver (mreceiver,filter);                                                  Registered broadcast Intentfilter Filter2=new  intentfilter (bluetoothadapter.action_discovery_finished);   Filter out the scanning end registerreceiver (mreceiver,filter2);                                                 //Registered broadcast 

4 Bluetooth pairing

 public  void   Createbond (Bluetoothdevice Btdev, Handler Handler) { if  (Btdev.getbondstate () == Bluetoothdevice.bond_none) { //  If this device cancels pairing, try pairing  if  (Build.VERSION.SDK_INT >= Build.version_codes.            KITKAT) {//Android version greater than or equal to 4.3 btdev.createbond (); }}  else  if  (btdev.getbondstate () = =  bluetoothdevice.bond_bonded) { //  If this device is already paired, try connecting to   Connect (Btdev, handler); }    }
 

5 Bluetooth connection

Private voidConnect (bluetoothdevice Btdev, Handler Handler) {Try {            //connect through the UUID that is negotiated with the serverMbluetoothsocket =Btdev.createrfcommsockettoservicerecord (BLTCONTANT.SPP_UUID); if(Mbluetoothsocket! =NULL)                //There is only one Bluetooth in the global, so we can save this socket object in AppliactionBltappliaction.bluetoothsocket =Mbluetoothsocket; LOG.I ("BlueTooth", "Start connection ..."); //called before it is established            if(Getmbluetoothadapter (). isdiscovering ())//Stop SearchGetmbluetoothadapter (). Canceldiscovery (); //if the current socket is in a non-connected state, the connection is called            if(!Getmbluetoothsocket (). isconnected ()) {                //you should make sure that the device does not perform the search device operation when you call Connect (). //If the search device is also at the same time, the connection rate will be significantly reduced and the connection will fail to a large extent. getmbluetoothsocket (). connect (); } log.i ("BlueTooth", "Already connected"); if(Handler = =NULL)return; //Result CallbackMessage message =NewMessage (); Message.what= 4; Message.obj=Btdev;        Handler.sendmessage (message); } Catch(Exception e) {log.i ("BlueTooth", "... Connection Failed "); Try{getmbluetoothsocket (). Close (); } Catch(IOException E1) {e1.printstacktrace ();        } e.printstacktrace (); }    }

6 Bluetooth communication

(1) Send a message

 Public Static voidsendMessage (String message) {if(Bltappliaction.bluetoothsocket = =NULL|| Textutils.isempty (message))return; Try {            //message + = "\ n";OutputStream OutputStream =BltAppliaction.bluetoothSocket.getOutputStream (); Outputstream.write (Message.getbytes ("Utf-8"));        Outputstream.flush (); } Catch(IOException e) {e.printstacktrace (); }    }}

(2) Receiving messages

 Public Static voidreceiveMessage (Handler Handler) {if(Bltappliaction.bluetoothsocket = =NULL|| Handler = =NULL)return; Try{InputStream InputStream=BltAppliaction.bluetoothSocket.getInputStream (); byte[] buffer =New byte[200];            Inputstream.read (buffer); LOG.I ("Information received by Boye",NewString (buffer)); Message Message=NewMessage (); Message.obj=NewString (buffer); Message.what= 1;                  Handler.sendmessage (message); } Catch(IOException e) {e.printstacktrace (); }    }

Android Bluetooth Learning