CODEWITHSUNDEEP
androidbluetootharduino
user1717504
user1717504

Reputation: 31

Android - Receiving strange bits from Arduino via Bluetooth

I am writing software for Android for communication between Arduino and Android.

The Arduino sends data using serial.println - I send the text "It works!".

The Android is receiving data in this way:

bytes = mmInStream.read(buffer);
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer).sendToTarget();

And it displays some code instead of "it works!", more exactly it displays [B@40e3f9b8.

What is the reason and how can this problem be fixed?

Upvotes: 2

Views: 847

Answers (2)

Анатолий Колтыков
Анатолий Колтыков

Reputation: 99

You have to create a string from a byte array: String strIncom = new String(buffer, 0, msg.arg1); Full example with \r\n handler:

    h = new Handler() {
    public void handleMessage(android.os.Message msg) {
        switch (msg.what) {
        case RECIEVE_MESSAGE:                                                   // if receive massage
            byte[] readBuf = (byte[]) msg.obj;
            String strIncom = new String(readBuf, 0, msg.arg1);                 // create string from bytes array
            sb.append(strIncom);                                                // append string
            int endOfLineIndex = sb.indexOf("\r\n");                            // determine the end-of-line
            if (endOfLineIndex > 0) {                                           // if end-of-line,
                String sbprint = sb.substring(0, endOfLineIndex);               // extract string
                sb.delete(0, sb.length());                                      // and clear
                txtArduino.setText("Data from Arduino: " + sbprint);            // update TextView
            }
            //Log.d(TAG, "...String:"+ sb.toString() +  "Byte:" + msg.arg1 + "...");
            break;
        }
    };
};

See full example program with apk and sources here

Upvotes: 1

nneonneo
nneonneo

Reputation: 179392

You just tried to print a byte array. In Java, that just prints out the type of the object [B, followed by its address @40e3f9b8.

If you want to print the text out, use new String(bytes) to get a string from the bytearray (using the default charset), then print the string out.

Upvotes: 3

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