級聯字符串

Question

NSMutableArray * oneText = [[NSMutableArray alloc] init]; 
[oneText addObject:[arraySystem objectAtIndex:[countImage intValue]]]; 
[oneText addObject:@".png"]; 
NSString *oneTextText=[oneText objectAtIndex:0]; 
[oneTextText stringByAppendingString:[oneText objectAtIndex:1]]; 
NSLog(oneTextText); 

爲什麼上面的代碼不能打印'Lenght.png'？作爲[arraySystem objectAtIndex:[countImage intValue]]等於「Lenght」 只會打印「Lenght」

Answer 1

把「oneTextText =」呼叫stringByAppendingString的時候，它應該是：

oneTextText = [oneTextText stringByAppendingString:[oneText objectAtIndex:1]];