Working with BLE Android 4.3 how to write characteristics?

Question

I am working on a BLE project (Android application) using Android 4.3 API, i have used sample BLE app it is only reading characteristics in DeviceControlActivity.activity, b

Answer 1

The following code is write characteristic using string data in utf-8 format:

public void writeCharacteristic(BluetoothGattCharacteristic characteristic,
            String data) {
        if (mBluetoothAdapter == null || mBluetoothGatt == null) {
            Log.w(TAG, "BluetoothAdapter not initialized");
            return;
        }

        Log.i(TAG, "characteristic " + characteristic.toString());
        try {
            Log.i(TAG, "data " + URLEncoder.encode(data, "utf-8"));

            characteristic.setValue(URLEncoder.encode(data, "utf-8"));

            // TODO
            mBluetoothGatt.writeCharacteristic(characteristic);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }

Hope it helps!

Answer 2

Please note that the logic OR in:
if ((charaProp | BluetoothGattCharacteristic.PROPERTY_READ) > 0)" in the original post should be a logic AND for the permission check to work. Same for the second charaProp comparison. Otherwise bot statements are true regardless of the actual permission flag.

Answer 3

The following code is write characteristic using byte[] data:

    public boolean writeCharacteristic(){

    //check mBluetoothGatt is available
    if (mBluetoothGatt == null) {
        Log.e(TAG, "lost connection");
        return false;
    }
    BluetoothGattService Service = mBluetoothGatt.getService(your Services);
    if (Service == null) {
        Log.e(TAG, "service not found!");
        return false;
    }
    BluetoothGattCharacteristic charac = Service
            .getCharacteristic(your characteristic);
    if (charac == null) {
        Log.e(TAG, "char not found!");
        return false;
    }

    byte[] value = new byte[1];
    value[0] = (byte) (21 & 0xFF);
    charac.setValue(value);
    boolean status = mBluetoothGatt.writeCharacteristic(charac);
    return status;
}

Answer 4

public boolean writeCharacteristic(byte value[],int type){
    //check mBluetoothGatt is available
    if (mBluetoothGatt == null) {
        Log.e(TAG, "lost connection");
        return false;
    }
    BluetoothGattService Service = mBluetoothGatt.getService(UUID_SIMPLESERVICE);
    if (Service == null) {
        Log.e(TAG, "service not found!");
        //////////NO service found...........
         return false;
    }
    BluetoothGattCharacteristic charac1 = null;
    boolean status1 = false;

    if(type==1) {
        charac1 = Service.getCharacteristic(UUID_PORT1);
        charac1.setValue(value);
        status1 = mBluetoothGatt.writeCharacteristic(charac1);
        Log.v("________BLESERVICE____", "___WRITE CHARATERISTICS STATUS:_________"+status1);
        onReliableWriteCompleted(status1);
    }
    if (charac1 == null) {
        Log.e(TAG, "char not found!");
        return false;
    }

    Log.v("___TYPE___","______________________"+type);
    return status1;
}