call to setter gives unrecognized selector error - ios

Question

I'm trying to subclass NSString to give it a property that is another NSString. No matter what I try with #synthesize or #dynamic or manually coding my setters and getters, I keep getting this "unrecognized selector sent to instance" error when I compile.
I know this has probably already been answered but after looking through about 15 other "unrecognized selector" questions on this site I am still at a loss. Sorry, I started coding VERY recently so I'm probably just missing something exceedingly simple.
Furigana.h
#interface Furigana : NSString
#property (strong, nonatomic) NSString *forKanji;
-(void)setForKanji:(NSString *)forKanji; //fails the same with or without this line
#end
Furigana.m
#import "Furigana.h"
#implementation Furigana
#synthesize forKanji = _forKanji;
//#dynamic forKanji; tried this
-(NSString *)forKanji { //also fails when custom setter/getters are left out
if(!_forKanji) _forKanji = [[NSString alloc] init];
return _forKanji;
}
-(void)setForKanji:(NSString *)forKanji {
if(!_forKanji) _forKanji = [[NSString alloc] init];
_forKanji = forKanji;
}
#end
Reibun.m
#import "Furigana.h"
-(NSArray *)parseFurigana:(NSArray *)unparsedData {
NSMutableArray *furigana = [[NSMutableArray alloc] init]; //of Furigana
for(unsigned int x = 0; x < [unparsedData count]; x++){
NSArray *components = [[NSArray alloc] init];
components = [[unparsedData objectAtIndex:x] componentsSeparatedByString:#":"];
Furigana *newFurigana = [[Furigana alloc] init];
newFurigana = [components objectAtIndex:1];
NSLog(#"stored string: %#",newFurigana); //so far so good
newFurigana.forKanji = [components objectAtIndex:0]; //crash
//[newFurigana setForKanji:[components objectAtIndex:0]]; //this fails too
[furigana addObject:newFurigana];
}
return furigana;
}

Answer 1

Here is the line that breaks your code:
newFurigana = [components objectAtIndex:1];
It replaces the object that you have allocated using [[Furigana alloc] init] with an NSString object, which does not respond to setForKanji: selector.
The assignment replaces newFurigana object, not the content of it. The content cannot be changed, because you derive from NSString, which is immutable.
Replace the init with initWithString, call [super initWithString:] from it, and make the initialization inside your loop look like this:
Furigana *newFurigana = [[Furigana alloc] initWithString:[components objectAtIndex:1]];