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Apps BLE Application (Display data from characteristic in a textView)

djboi2011

Well-Known Member
I used the BluetoothLeGatt example code to write an app that automatically connects to a bonded BLE peripheral upon launching the app. Now i am trying to display the data from one of the peripheral's characteristic in a textView. The BluetoothLeGatt example code only demonstrates this using ExpandableListView.OnChildClickListener, my app should require no user input and simply get he data from the characteristic. This is what i have so far:

Code:
 private TextView mConnectionState;
private TextView mDataField;
private String mDeviceName;
private String mDeviceAddress;
private ExpandableListView mGattServicesList;
private BluetoothLeService mBluetoothLeService;
private boolean mConnected = false;
private BluetoothGattCharacteristic mNotifyCharacteristic;

private final String LIST_NAME = "NAME";
private final String LIST_UUID = "UUID";

// Code to manage Service lifecycle.
private final ServiceConnection mServiceConnection = new ServiceConnection() {

    @Override
    public void onServiceConnected(ComponentName componentName, IBinder service) {
        mBluetoothLeService = ((BluetoothLeService.LocalBinder) service).getService();
        if (!mBluetoothLeService.initialize()) {
            Log.e(TAG, "Unable to initialize Bluetooth");
            finish();
        }
        // Automatically connects to the device upon successful start-up initialization.
        mBluetoothLeService.connect(mDeviceAddress);
    }

    @Override
    public void onServiceDisconnected(ComponentName componentName) {
        mBluetoothLeService = null;
    }
};

// Handles various events fired by the Service.
// ACTION_GATT_CONNECTED: connected to a GATT server.
// ACTION_GATT_DISCONNECTED: disconnected from a GATT server.
// ACTION_GATT_SERVICES_DISCOVERED: discovered GATT services.
// ACTION_DATA_AVAILABLE: received data from the device.  This can be a result of read
//                        or notification operations.
private final BroadcastReceiver mGattUpdateReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        final String action = intent.getAction();
        if (BluetoothLeService.ACTION_GATT_CONNECTED.equals(action)) {
            mConnected = true;
            updateConnectionState(R.string.connected);
            mConnectionState.setTextColor(Color.parseColor("#FF17AA00"));
            invalidateOptionsMenu();
        } else if (BluetoothLeService.ACTION_GATT_DISCONNECTED.equals(action)) {
            mConnected = false;
            updateConnectionState(R.string.disconnected);
            invalidateOptionsMenu();
            clearUI();
        } else if (BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED.equals(action)) {
*edit*
           UUID chara = UUID.fromString("c97433f0-be8f-4dc8-b6f0-5343e6100eb4");
            List<BluetoothGattService> servs = mBluetoothLeService.getSupportedGattServices();
                for (int i = 0; servs.size() > i; i++) {

                    List<BluetoothGattCharacteristic> charac = servs.get(i).getCharacteristics();
                    for (int j = 0; charac.size() > i; i++) {
                         BluetoothGattCharacteristic ch = charac.get(i);
                        if (ch.getUuid() == chara) {
                            mBluetoothLeService.readCharacteristic(ch);
                            mBluetoothLeService.setCharacteristicNotification(ch, true);

                        }
                    }
                }
        } else if (BluetoothLeService.ACTION_DATA_AVAILABLE.equals(action)) {
            displayData(intent.getStringExtra(BluetoothLeService.EXTRA_DATA));
        }
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_device_control);

    final Intent intent = getIntent();
    mDeviceName = intent.getStringExtra(EXTRAS_DEVICE_NAME);
    mDeviceAddress = intent.getStringExtra(EXTRAS_DEVICE_ADDRESS);
    mConnectionState = (TextView) findViewById(R.id.connection_state);
    mDataField = (TextView) findViewById(R.id.data);

    Intent gattServiceIntent = new Intent(this, BluetoothLeService.class);
    bindService(gattServiceIntent, mServiceConnection, BIND_AUTO_CREATE);
    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);






}
@Override
protected void onResume() {
    super.onResume();
    registerReceiver(mGattUpdateReceiver, makeGattUpdateIntentFilter());
    if (mBluetoothLeService != null) {
        final boolean result = mBluetoothLeService.connect(mDeviceAddress);
        Log.d(TAG, "Connect request result=" + result);
    }

}

@Override
protected void onPause() {
    super.onPause();
    unregisterReceiver(mGattUpdateReceiver);
}

@Override
protected void onDestroy() {
    super.onDestroy();
    unbindService(mServiceConnection);
    mBluetoothLeService = null;
}

private void updateConnectionState(final int resourceId) {
    runOnUiThread(new Runnable() {
        @Override
        public void run() {
            mConnectionState.setText(resourceId);
        }
    });
}

private void displayData(String data) {
    if (data != null) {
        mDataField.setText(data);
    }
}

private void clearUI() {
    mGattServicesList.setAdapter((SimpleExpandableListAdapter) null);
    mDataField.setText(R.string.no_data);
}




private static IntentFilter makeGattUpdateIntentFilter() {
    final IntentFilter intentFilter = new IntentFilter();
    intentFilter.addAction(BluetoothLeService.ACTION_GATT_CONNECTED);
    intentFilter.addAction(BluetoothLeService.ACTION_GATT_DISCONNECTED);
    intentFilter.addAction(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED);
    intentFilter.addAction(BluetoothLeService.ACTION_DATA_AVAILABLE);
    return intentFilter;
}

I've successfully connected to an already bonded device, but now im trying to get the data from a characteristic using its uuid and display it in a textView. The BluetoothLeGatt example shows how a characteristic is selected by a user using an expandable list view onclick listener displaying the supported characteristics. I want to bypass all that and just get the data from the characteristic with the known uuid.

-EDIT-
figured it out
 
Last edited:
Did you ever finish this code, I am looking to write something very similar.
I have the BluetoothLEGatt example working with my data but would like to have it automated to the bonded device....
 
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