CODEWITHSUNDEEP
androidbluetoothbluetooth-lowenergyrxandroidble
yusufonderd
yusufonderd

Reputation: 3247

GATT 137 exception when read characteristic

I'm using RxAndroidBle library for connecting bluetotooth device. I'm getting GATT 137 exception when I read characteristic of bluetooth device. Why I can't read characteristic ? Code snippet: 

 if (device.connectionState == RxBleConnection.RxBleConnectionState.CONNECTED) {
         rxConnection.readCharacteristic(ConstantsBle.deviceUUIDCharacteristic).subscribe({
             Log.e(TAG, "read characteristic task is success")
         }, {
             it.printStackTrace()
         })
     }

Exception details :

W/System.err: com.polidea.rxandroidble.exceptions.BleGattCharacteristicException: GATT exception from MAC address 0C:F3:EE:2A:ED:49, status 137, type BleGattOperation{description='CHARACTERISTIC_READ'}. (Look up status 0x89 here https://android.googlesource.com/platform/external/bluetooth/bluedroid/+/android-5.1.0_r1/stack/include/gatt_api.h) W/System.err: at com.polidea.rxandroidble.internal.connection.RxBleGattCallback.propagateErrorIfOccurred(RxBleGattCallback.java:227) W/System.err: at com.polidea.rxandroidble.internal.connection.RxBleGattCallback.access$800(RxBleGattCallback.java:32) W/System.err: at com.polidea.rxandroidble.internal.connection.RxBleGattCallback$2.onCharacteristicRead(RxBleGattCallback.java:108) at android.bluetooth.BluetoothGatt$1.onCharacteristicRead(BluetoothGatt.java:286) W/System.err: at android.bluetooth.IBluetoothGattCallback$Stub.onTransact(IBluetoothGattCallback.java:117) W/System.err: at android.os.Binder.execTransact(Binder.java:565)

Upvotes: 0

Views: 2809

Answers (1)

Dariusz Seweryn
Dariusz Seweryn

Reputation: 3222

You cannot read the characteristic because the authentication with your peripheral has failed.

The status code: 137 (0x89 hex) is described in the Android sources. You even have the link in logs you have pasted.

There can be several reasons for this situation:

  1. The central could not establish a bond with the peripheral
  2. An already existing bond has been dropped by one of the sides (there are known bugs in Android)
  3. The pairing has been just established for the current connection—in this situation you could retry the read and it should succeed

Note that pairing and bonding are two different things in BLE although are often used interchangeably.

Pairing is a short term process that is scoped for a particular connection whereas bonding is pairing with subsequent exchange of encryption keys (these can be then reused for next pairings).

Upvotes: 1

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