在Android中通过蓝牙发送字符串（字节）

Question

I'm implementing sending data through Bluetooth in Android between two Android devices. For simplicity, I'll mostly likely pass strings and parse them as JSON or other string format.

Now I'm wondering, how should I read the data to be sure, that I've received all of them? Currently I'm taking the following approach:

byte[] buffer = new byte[1024];

while (!finished) {

    // My class
    MemoryStream ms = new MemoryStream();

    int bytesRead = 0;
    do {
        bytesRead = input.read(buffer, 0, buffer.length);
        ms.write(buffer, 0, bytesRead);
    } while (bytesRead == buffer.length);

    // Now process data
}

However, this will work only if inputStream.read() will always return as many bytes as were sent on the other device.

For example, I'm assuming, that if first device sends 1234 bytes, first call to read will return 1024 and second 210. Or if first device sends 1024 bytes, first call to read will return 1024 bytes and second - -1 (stream end).

Am I right? Or should I implement my own mechanism of determining, whether all sent data was received (or should I wait for more to complete current chunk)?

Answer 1

The answer is: no . It is possible, that transmission will end (in terms of input.read ) and not the whole sent buffer is transferred.

One has to guard transmission, preferably by preceeding the data with their size in bytes and then read data until all of them are transferred.