nilsi nilsi - 1 month ago 11
Android Question

Totally Disconnect a Bluetooth Low Energy Device

I connect to a BLE device with the

connectGatt()
method in Android. This works great.

When I disconnect I use the following:

private void disconnectDevice() {
gatt.disconnect();
}


When I receive the callback I do a close.

private BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
switch (newState) {
case BluetoothProfile.STATE_CONNECTED:
Log.d("BLED-GATT", "STATE_CONNECTED");
setUIConnectionStatus("Discover services on device...", Color.YELLOW);
checkEnableAddButton(simpleTrackEditText.getText().toString());
gatt.discoverServices();
break;
case BluetoothProfile.STATE_DISCONNECTED:
Log.d("BLED-GATT", "STATE_DISCONNECTED");
setUIConnectionStatus("Not Connected!", Color.RED);
gatt.close();
break;
default:
Log.d("BLED-GATT", "STATE_OTHER");
}
}
}


This is executed and I can no longer control the device after calling
disconnectDevice()
. The device itself seems to think that it is still connected since I cant put it in broadcasting visibility mode (which happens if it already has a connection). However, if I kill the application and open it again then I can set the device in broadcasting mode. This tells me the app was not properly disconnected.

Any idea what I missed here?

Answer

The problem was that I during scanning was connecting to the same device multiple times causing my application to have many connections open at the same time. Adding !isConnected() solved the problem:

/**
 * Connects to the device. Does nothing if already connected.
 * @param macAddress the address of the device.
 */
private void connectDevice(String macAddress) {
    if (!isConnected()) {
        device = bluetoothAdapter.getRemoteDevice(macAddress);

        if (device == null) {
            this.sendToast("Device Not Available");
        } else {
            Log.d("BLED", "Connecting...");
            gatt = device.connectGatt(this, true, gattCallback);
        }
    }
}