onServicesDiscovered not be called on BluetoothGat

问题:

I start working with ibeacon and android. But there are some problem need for your helps. On blutoothGatCallback I implement onConnectionStateChange and call discoverServices(). Althougth, discoverServices() return true but there is not any callback execute, I hope onServicesDiscovered being called, but not.

@Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status,
            int newState) {
        Log.i(TAG, "onConnectionStateChange : " + status + "  newState : "
                + newState);
        if (newState == BluetoothProfile.STATE_CONNECTED) {

            boolean isdiscover= mBluetoothGatt.discoverServices();
            if(isdiscover){
            mConnected = true;              
            }
        } 

    }

Status is 133 and newstate is connected. Does status make it fail to get callback

回答1:

More information would be helpful, can you supply the received Advertisement data?

The following is just a guess as theres a broad range of issues around with Android BLE, however i seen this general 133 error already when accidentally issuing a BR/EDR connection to a Beacon.

As Android defaults to a BR/EDR connection when the GATT-server device advertises support for it, you can try to explicitely set the transport to TRANSPORT_LE in connectGatt(), however since this parameter is only aviable in the hidden version of it, you need to use reflection.

Try to issue the connection like this:

private BluetoothGatt mGatt;
private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() { ... }

public void connectToDevice(BluetoothDevice device) {
        try {
            Method m = device.getClass().getDeclaredMethod("connectGatt", Context.class, boolean.class, BluetoothGattCallback.class, int.class);
            int transport = device.getClass().getDeclaredField("TRANSPORT_LE").getInt(null);
            mGatt = (BluetoothGatt) m.invoke(device, this, false, gattCallback, transport);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        }
    }

That way you can at least be sure its not related to this Android behaviour.

回答2:

Status 133 can indicate that you try to execute bt commands on a non-main thread.

The BTLE callbacks are called from android-bt-binder threads.

So

mBluetoothGatt.discoverServices();

runs on the binder thread and it should run on the GUI/main thread