Java Development

[dmravyan]

I am sending a stream of bytes via a bluetooth module to the blackberry.

I am then taking the substrings from the data received.

For some reason I am getting 3 extra bytes of data from somewhere....

I have setup a dialog.alert which displays the data stream correctly after it is received by the dataReceived(int length) method.

Stream sent:

"STA152535455565"

Dialog.alert(_dataReceived); // equal to STA152535455565

this is where it gets weird:

_lblS1.setText(_dataReceived.substring(2, 4)); //Returns: ST   should be 15 

_lblS2.setText(_dataReceived.substring(4, 6)); //Returns: A1   should be 25

etc...

when I change the substring(2,4) to substring(5,7) it returns 15

Any ideas?

Thanks!

David

Curve8300+JDE4.5(eclipse)

[jonberry]

A little more code might be helpful...

How are you getting data into _dataRecevied?

[dmravyan]

Hi,

I am getting the data into _dataReceived based on the Bluetooth example provided by RIM.

 // Invoked when data has been received.
	    public void dataReceived(int length)
	    {
     int len;
     try
     {
	            // Read the data that arrived.
  if((len = _port.read(_receiveBuffer, 0, length == -1 ? _receiveBuffer.length : length)) != 0)
	            {
	           if(len == 1 && _receiveBuffer[0] == '\r')
	                    {
	                        _receiveBuffer[1] = '\n';
	                        ++len;
	                    }


              _data.append(new String( _receiveBuffer, 0, len));
	            
	     _dataReceived = _data.toString();
	            	                
	            }
	            
	            DataProcess();
	        } catch(IOException ioex)
	        {
	            // Catch and re-throw the exception.
	            throw new RuntimeException(ioex.toString());
	        }
	    }

In DataProcess I placed the substring code.

[peter_strange]

Be aware that the length provided as the parameter to dataReceived is a minimum, there could be more data by the time you get to do your read.  However I think your code copes with that.

What is actually in the extra bytes you receive?

Have you considering dumping _receiveBuffer out in integer form - for example to see if there are some funny characters in there that you won't see on your 'display'?

[dmravyan]

I played around with the code some more. I am starting to think the first two characters are blank for some reason.

Stream Sent:

MON182838485868

Code dealing with stream:

Dialog.alert(_dataReceived);           //Shows MON182838485868....

_lblS1.setText(_dataReceived.substring(0, 5));             //      S1 shows MON   <-- and some extra spacing after  

 _lblS2.setText(_dataReceived.substring(7, 9));             //      S2 shows 28  

_lblS3.setText(_dataReceived.substring(0));                //       S3 shows MON182838485868

_lblS4.setText(_dataReceived, 0, 3);                           //       S4 shows M

_lblS5.setText(_dataReceived.getBytes());                   //      S5 shows MON182838485868 

_lblS6.setText(_dataReceived);                                 //        S6 shows " " blank... getBytes changed _dataReceived?

Thanks,

David

[dmravyan]

For now I have fixed the issue by simply removing the first two characters from the _dataReceived

_dataReceived = _dataReceived.substring(2,_dataReceived.length());

I placed the code right after _dataReceived is first written....

I think I might have a problem with my other device sending a couple of blank characters at start.

Thanks for your help...

[bikas · Accepted solution]

Some extra blank space can be added to the begin and also can be added at the end of the receive data. I don't know the reason.

But i think in this case it would be more appropriate to use:

     _dataReceived = _dataReceived.trim();

Regards

Bikas 

[dmravyan]

Thanks! much better!!