Android 4.3: How to connect to multiple Bluetooth Low Energy devices? -

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task:

i developing android application need simultaneously connect multiple (identical, can differentiated via id) ble chip devices in order send , receive updates. have used tutorials on google's official web page:

http://developer.android.com/guide/topics/connectivity/bluetooth-le.html

this has helped me create devicescanactivity java class allows me scan , list of available ble devices in close proximity, applications of type do. found out 7 external slaves can connected same master device simultaneously. however, implementing communication still unclear me. useful link is:

android 4.3: how connect multiple bluetooth low energy devices

however, not provide enough detail me understand how such implementation works.

i have been researching topic while , not able find example implementations. aware question has been asked lot of times there not seem working solution/ demo available online make things more clear me. appreciate lot if can point me resource/ working solution explain in detail steps necessary modify existing java class in order implement functionality.

devicescanactivity.java:

import android.app.activity; import android.app.listactivity; import android.app.progressdialog; import android.bluetooth.bluetoothadapter; import android.bluetooth.bluetoothdevice; import android.bluetooth.bluetoothmanager; import android.content.context; import android.content.intent; import android.content.sharedpreferences; import android.content.pm.packagemanager; import android.os.bundle; import android.os.handler; import android.view.layoutinflater; import android.view.menu; import android.view.menuitem; import android.view.view; import android.view.viewgroup; import android.widget.baseadapter; import android.widget.listview; import android.widget.textview; import android.widget.toast;  import java.util.arraylist;  /**  * activity scanning , displaying available bluetooth le devices.  */ public class devicescanactivity extends listactivity {     private ledevicelistadapter mledevicelistadapter;     private bluetoothadapter mbluetoothadapter;     private boolean mscanning;     private handler mhandler;      private static final int request_enable_bt = 1;     // stops scanning after 10 seconds.     private static final long scan_period = 10000;      private static final string config_file = "file";      private int _countclick = 0;     private boolean experimentermode = false;     private string paireddeviceaddress = "";        @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         getactionbar().settitle(r.string.title_devices);         mhandler = new handler();          // use check determine whether ble supported on device.  can         // selectively disable ble-related features.         if (!getpackagemanager().hassystemfeature(packagemanager.feature_bluetooth_le)) {             toast.maketext(this, r.string.ble_not_supported, toast.length_short).show();             finish();         }          // initializes bluetooth adapter.  api level 18 , above, reference         // bluetoothadapter through bluetoothmanager.         final bluetoothmanager bluetoothmanager =                 (bluetoothmanager) getsystemservice(context.bluetooth_service);         mbluetoothadapter = bluetoothmanager.getadapter();          // checks if bluetooth supported on device.         if (mbluetoothadapter == null) {             toast.maketext(this, r.string.error_bluetooth_not_supported, toast.length_short).show();             finish();             return;         }     }      @override     public boolean oncreateoptionsmenu(menu menu) {         getmenuinflater().inflate(r.menu.main, menu);         if (!mscanning) {             menu.finditem(r.id.menu_stop).setvisible(false);             menu.finditem(r.id.menu_scan).setvisible(true);             menu.finditem(r.id.menu_refresh).setactionview(null);         } else {             menu.finditem(r.id.menu_stop).setvisible(true);             menu.finditem(r.id.menu_scan).setvisible(false);             menu.finditem(r.id.menu_refresh).setactionview(                     r.layout.actionbar_indeterminate_progress);         }         return true;     }      @override     public boolean onoptionsitemselected(menuitem item) {         switch (item.getitemid()) {             case r.id.menu_scan:                 mledevicelistadapter.clear();                 scanledevice(true);                 break;             case r.id.menu_stop:                 scanledevice(false);                 break;             case android.r.id.home:                 //onbackpressed();                 _countclick++;                 if(_countclick>8)                 {                     toggleexperimentermode();                 }                 return true;         }         return super.onoptionsitemselected(item);     }      @override     protected void onresume() {         super.onresume();          // ensures bluetooth enabled on device.  if bluetooth not enabled,         // fire intent display dialog asking user grant permission enable it.         if (!mbluetoothadapter.isenabled()) {             if (!mbluetoothadapter.isenabled()) {                 intent enablebtintent = new intent(bluetoothadapter.action_request_enable);                 startactivityforresult(enablebtintent, request_enable_bt);             }         }          // restore preferences         sharedpreferences settings = getsharedpreferences(config_file, 0);         experimentermode = settings.getboolean("experimentermode", false);         paireddeviceaddress = settings.getstring("paireddeviceaddress", "");          // initializes list view adapter.         mledevicelistadapter = new ledevicelistadapter();         setlistadapter(mledevicelistadapter);         scanledevice(true);     }      @override     protected void onactivityresult(int requestcode, int resultcode, intent data) {         // user chose not enable bluetooth.         if (requestcode == request_enable_bt && resultcode == activity.result_canceled) {             finish();             return;         }         super.onactivityresult(requestcode, resultcode, data);     }      @override     protected void onpause() {         super.onpause();         scanledevice(false);         mledevicelistadapter.clear();     }      @override     protected void onlistitemclick(listview l, view v, int position, long id) {         final bluetoothdevice device = mledevicelistadapter.getdevice(position);         if (device == null) return;         connecttodevice(device);     }        private void connecttodevice(bluetoothdevice device){         final intent intent = new intent(this, devicecontrolactivity.class);         intent.putextra(devicecontrolactivity.extras_device_name, device.getname());         intent.putextra(devicecontrolactivity.extras_device_address, device.getaddress());         if (mscanning) {             mbluetoothadapter.stoplescan(mlescancallback);             mscanning = false;         }          sharedpreferences settings = getsharedpreferences(config_file, 0);         sharedpreferences.editor editor = settings.edit();         editor.putstring("paireddeviceaddress", device.getaddress());         editor.commit();          startactivity(intent);     }      //---------------------------------------------------      private void scanledevice(final boolean enable) {         progressdialog progress;         if (enable) {             // stops scanning after pre-defined scan period.             mhandler.postdelayed(new runnable() {                 @override                 public void run() {                     mscanning = false;                     mbluetoothadapter.stoplescan(mlescancallback);                     invalidateoptionsmenu();                 }             }, scan_period);              mscanning = true;             mbluetoothadapter.startlescan(mlescancallback);         } else {             mscanning = false;             mbluetoothadapter.stoplescan(mlescancallback);          }         invalidateoptionsmenu();     }      private void toggleexperimentermode(){         _countclick=0;         experimentermode = !experimentermode;         sharedpreferences settings = getsharedpreferences(config_file, 0);         sharedpreferences.editor editor = settings.edit();         editor.putboolean("experimentermode", experimentermode);         editor.commit();         string t = experimentermode ? "you in experimenter mode":"you in user mode";         toast.maketext(this, t, toast.length_short).show();     }      // adapter holding devices found through scanning.     private class ledevicelistadapter extends baseadapter {         private arraylist<bluetoothdevice> mledevices;         private layoutinflater minflator;          public ledevicelistadapter() {             super();             mledevices = new arraylist<bluetoothdevice>();             minflator = devicescanactivity.this.getlayoutinflater();         }          public void adddevice(bluetoothdevice device) {             if(!mledevices.contains(device)) {                 mledevices.add(device);             }             if (!experimentermode && ! paireddeviceaddress.isempty()) {                 if (device.getaddress().equals(paireddeviceaddress)) {                     connecttodevice(device);                 }             }         }          public bluetoothdevice getdevice(int position) {             return mledevices.get(position);         }          public void clear() {             mledevices.clear();         }          @override         public int getcount() {             return mledevices.size();         }          @override         public object getitem(int i) {             return mledevices.get(i);         }          @override         public long getitemid(int i) {             return i;         }          @override         public view getview(int i, view view, viewgroup viewgroup) {             viewholder viewholder;             // general listview optimization code.             if (view == null) {                 view = minflator.inflate(r.layout.listitem_device, null);                 viewholder = new viewholder();                 viewholder.deviceaddress = (textview) view.findviewbyid(r.id.device_address);                 viewholder.devicename = (textview) view.findviewbyid(r.id.device_name);                 view.settag(viewholder);             } else {                 viewholder = (viewholder) view.gettag();             }              bluetoothdevice device = mledevices.get(i);             final string devicename = device.getname();             if (devicename != null && devicename.length() > 0)                 viewholder.devicename.settext(devicename);             else                 viewholder.devicename.settext(r.string.unknown_device);             viewholder.deviceaddress.settext(device.getaddress());              return view;         }     }      // device scan callback.     private bluetoothadapter.lescancallback mlescancallback =             new bluetoothadapter.lescancallback() {          @override         public void onlescan(final bluetoothdevice device, int rssi, byte[] scanrecord) {             runonuithread(new runnable() {                 @override                 public void run() {                     mledevicelistadapter.adddevice(device);                     mledevicelistadapter.notifydatasetchanged();                 }             });         }     };      static class viewholder {         textview devicename;         textview deviceaddress;     } }

current information:

all of these pages contain directions, not provide enough detail on how multiple connections can implemented.

ui target representation:

diagram

the idea 5.1.1 android nexus 7 device able connect @ 5 ble chip slaves , send/receive updates.


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