iphone - Thread extracting substring from NSString -

i'm doing work using redpark serial cable ios. cable allows serial communication between ios device , device microcontroller.

there method comes redpark sdk reads bytes available on serial line. method called anytime cable receives informatino.

(void)readdatabytes(uint32 bytes) {    nsstring *s = [[nsstring alloc] initwith...bytes];    nsstring *editedstring = [self extractsubstringmethod:s];    [myarray addobject:editedstring]; } 

the microcontroller sending information in following format

<msg>xxxxxxxxxxxxx</msg> 

i want able extract x's message (which taken in nsstring). @ moment i'm using nsrange extract after position 4 (the first x) , before final "< /msg>" i'm not convinced works , wondering there other ideas?

finally, have nsthread running alongside this, have messages being added nsmutablearray. want is, nsthread manipulating/displaying message information when there message received cable. have following

//thread method,  while([myarray count] > 0) //don't believe neccesary in anyway {   for(int = 0; < [myarray count]; i++){     nsstring *string = [myarray objectat(i)];     [self displaystring:string];     [myarray removeobjectat(i);     } } 

i believe it's crashing around above... [self displaystring:string] sets value of label,

-(void)displaystring(nsstring *string) {  label.text = [string charat(1)]; } 

the code above memory i've left mac @ home , i'm in work. suggestions/help appreciated

instead of

while([myarray count] > 0) //don't believe neccesary in anyway {   for(int = 0; < [myarray count]; i++){     nsstring *string = [myarray objectat(i)];     [self displaystring:string];     [myarray removeobjectat(i);     } } 

try this:

while ([myarray count] > 0) {     [self displaystring: myarray[0]];             [myarray removeobjectatindex: 0]; }