Question

我的代码中出现了未声明的标识符问题。已注释编译器消息。

的main.m

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])
{

     @autoreleasepool {

         NSMutableArray *stocks = [[NSMutableArray alloc]init];

         NSMutableDictionary *stock;

        stock = [NSMutableDictionary dictionary];
        [stock setObject:@"AAPL" 
                  forKey:@"symbol"];

        [stock setObject:[NSNumber numberWithInt:200]
                                        forKey:@"shares"];
                                [stocks addObject:stock];

         stock = [NSMutableDictionary dictionary];
         [stock = setObject:@"GOOG" // use of undeclared identifier 'setObject'
                     forKey:@"symbol"];
         [stock = setObject:[NSNumber numberWithInt:160] // use of undeclared identifier     'setObject'
                  forKey:@"shares"];
        [stocks addObject:stock];

        [stocks writeToFile:@"/tmp/stocks/plist" 
                 atomically:YES];



        }
    return 0;
}

Answer 1

你的问题是等号..

 [stock **=** setObject:@"GOOG" // use of undeclared identifier 'setObject'
                 forKey:@"symbol"];
     [stock **=** setObject:[NSNumber numberWithInt:160] // use of undeclared identifier     'setObject'
              forKey:@"shares"];

您的代码应该是..

 [stock  setObject:@"GOOG" // use of undeclared identifier 'setObject'
                 forKey:@"symbol"];
     [stock  setObject:[NSNumber numberWithInt:160] // use of undeclared identifier     'setObject'
              forKey:@"shares"];

Answer 2

你不做

[stock = setObject....

你直接做

[stock setObject....

这些方法不返回任何类型的值，它们是void方法（谈论-setObject方法）

Answer 3

你有[stock = setObject而不仅仅是[stock setObject：失去了等于。

Objective-C代码中未声明的标识符

3 个答案: