Question

Helo.

Im developing an application that transferes data over bluetooth(with a flight recorder device). When i am recieving a lot of data data(3000 – 40000 lines of text, depends of the file size) my aplication seems to stop recieving the data. I recieve the data with InputStream.read(buffer). For example: I send a command to the flight recorder, it starts sending me a file(line by line), on my phone i recieve 120 lines and then the app stucks.

Intresting is that on my HTC Desire the app stucks just sometimes, on the Samsung Galaxy S phone the application stucks every single time i try to recive more than 50 lines.

The code is based on the BluetoothChat example. This is the part of code where i am listening to the BluetoothSocket:

byte[] buffer = new byte[1024];
int bytes =0;

while(true)
{
    bytes = mmInStream.read(buffer); 
    readMessage = new String(buffer, 0, bytes);
    Log.e("read", readMessage);

    String read2 = readMessage;
    //searching for the end of line to count the lines(the star means the start of the checksum)
    int currentHits = read2.replaceAll("[^*]","").length(); 
    nmbrOfTransferedFligts += currentHits;
    .
    .
    .
    //parsing and saving the recieved data         

I must say that i am running this in a while(true) loop, in a Thread, that is implemented in an android Service. The app seems to stuck at “bytes = mmInStream.read(buffer);”
I have tried to do this with BufferedReader, but with no success.

Thanks.

Answer 1

The app seems to stuck at “bytes = mmInStream.read(buffer);”

But that is normal behavior: InputStream.read(byte[]) blocks when there is no more data available.

This suggests to me that the problem is on the other end or in the communication between the devices. Is is possible that you have a communication problem (which is a bit different on the Galaxy vs. the Desire) that is preventing more data from being received?

Also, I would suggest that you wrap a try/catch around the read statement to be sure that you catch any possible IOException’s. Though I guess you would have seen it in logcat if that were happening.

Speaking of logcat, I would suggest that you look at the logcat statements that Android itself it generating. I find that it generates a lot for Bluetooth and this might help you to figure out whether there really is any more data to be read().