android - No OnCharacteristicChanged callbacks when I write a characteristic in OnServiceDiscovered callback -


i have app need write , read characteristics ble device. both processes should done simultaneously. furthermore, need write before read.

i understand process not asynchronous. not have other option write characteristic after services discovered.

i can write these characteristic sucessfully, problem oncharacteristicchange never callbacks. if not onservicesdiscovered, oncharacteristicchange callback

any idea?

this code called onservicesdiscovered:

public void onservicesdiscovered(bluetoothgatt gatt, int status)     super.onservicesdiscovered(gatt, status);    writecharac(gatt.getservices()); }  private void writecharac(list<bluetoothgattservice> list) {   if (list == null)     return;  if (!indf) {    (bluetoothgattservice gattservice : list) {    list<bluetoothgattcharacteristic> gattcharacteristics = gattservice.getcharacteristics();        (final bluetoothgattcharacteristic gattcharacteristic : gattcharacteristics) {         if (writablecharac_uuid.equals(gattcharacteristic.getuuid())) {           indf = true;           break;         }       }       if (indf) {          break;       }    } }    if (indf) {     writecharac();   } else {     string intentaction = "string_action_connected";     broadcastupdate(intentaction, 0);   } }


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