Question

I have one problem to work with NSMutableData.

I defined one NSMutableData *receivedData, and tried to copy several NSData* data to the receivedData. I just called [receivedData appendData:data], but appears the data is not copied:

.... NSLog(@'get data! Received %d bytes of data',[data length]);   // output is not zero, say 1231.  [receivedData appendData:data]; NSLog(@'after append! length is %d bytes of data',[receivedData length]);   // showing zero 

Thanks.

Answer 1

Check if receivedData == nil. If so, then you might have forgotten to initialize it. For example:

receivedData = [[NSMutableData alloc] init]; 

Then release it when you don’t need it anymore:

[receivedData release]; receivedData = nil;