android - BLE - i am not able to read 2 characteristic one of temperature service and another of Battery service at same time -

this code discovering services , characteristic , setting descriptor both temperature , battery characteristic.

in starting discovering services temperature , battery. then,i discover characterstic each temperature , battery service , write descriptor both.

when run code,the call going oncharactersticchanged , got temperature result. but,call not going on oncharactersticread battery

    (bluetoothgattservice service : services) {                 log.e("asd service discoverd", service.getuuid().tostring());  //                check service should temperature service or battery service                 if (service.getuuid().equals(bt_thermo_service) || service.getuuid().equals(bt_battery_service)) {                     log.e("asd service discoverd", service.getuuid().tostring());                       list<bluetoothgattcharacteristic> characteristics = service.getcharacteristics();                      //                     // create compartor                     // sort list cpmparor                      // addd in queue                       // read same                       (bluetoothgattcharacteristic characteristic : characteristics) {                         log.e("asd charac discoverd:", characteristic.getuuid().tostring());                         if (characteristic.getuuid().equals(bt_real_time_temperature_charteristics) || characteristic.getuuid().equals(bt_batery_level_characteristics)) {                             log.e("asd charac discoverd:", characteristic.getuuid().tostring());                              arraylist.add(characteristic);                              // check if characterstic realtime temperature measurement characterstic  or battery level characterstic                             if (characteristic.getuuid().equals(bt_real_time_temperature_charteristics)) {                                 //indicate ble send temperature data each time when new data value found                                  //notify ble device send data                                 gatt.setcharacteristicnotification(characteristic, true);                                  (bluetoothgattdescriptor descriptor : characteristic.getdescriptors()) {                                     descriptor.setvalue(bluetoothgattdescriptor.enable_indication_value);                                     gatt.writedescriptor(descriptor);                                  }                             } else                             if (characteristic.getuuid().equals(bt_batery_level_characteristics)) {                                  //notify ble device send data                                 gatt.readcharacteristic(characteristic);                                  (bluetoothgattdescriptor descriptor : characteristic.getdescriptors()) {                                     descriptor.setvalue(bluetoothgattdescriptor.enable_notification_value);                                     gatt.writedescriptor(descriptor);                                  }                              }                         }                     }                   } 

these gattcallback methods.

 @override         public void oncharacteristicread(bluetoothgatt gatt, bluetoothgattcharacteristic characteristic, int status) {             super.oncharacteristicread(gatt, characteristic, status);             log.e("charvalu", "" + characteristic);             if (characteristic.getuuid().equals(bt_batery_level_characteristics)) {                 byte b[] = characteristic.getvalue();                 if (b.length != 0) {                     log.e("battery", integer.tostring(b.length)); //                    bytebuffer batterybuffer = bytebuffer.wrap(b); //                    long batterystatus = batterybuffer.getlong(); //                    log.e("battery","" + batterystatus);                  }             }         }      @override         public void oncharacteristicchanged(bluetoothgatt gatt, bluetoothgattcharacteristic characteristic) {             super.oncharacteristicchanged(gatt, characteristic);             log.e("inside char", "" + characteristic);             if (characteristic != null) {                 log.e("on change char", characteristic.getuuid().tostring());                  if (characteristic.getuuid().equals(bt_real_time_temperature_charteristics)) {                     log.e("on change inside", characteristic.getuuid().tostring());                      //temperature data comes in byte array of size 12                     byte b[] = characteristic.getvalue();                       if (b.length != 0) {                         //check header , tail of data packet                         if (b[0] == 0x7c && b[11] == 0x7d) {                             //temp reading stored in 7 , 8 byte                             bytebuffer tempbuffer = bytebuffer.wrap(b, 7, 2);                             tempbuffer.order(byteorder.little_endian);                             short temp = tempbuffer.getshort();                             final float ftemp = (float) (temp / 100.0);                             log.e("sunittemp", float.tostring(ftemp));                             runonuithread(new thread() {                                 @override                                 public void run() {                                     super.run();                                     workinglistener.unstablereading(new ivythermoreading(ftemp));                                  }                             });                         }                     }                 }             }         } 

unfortunately sending read , write requests @ once synchronously not work since android allows 1 pending gatt operation @ time. must somehow enqueue work , continue sending request once callback of previous request arrives.