cocoa - 使用 NSOperationQueue 和 block

Question

我在 Cocoa 中使用 addoperationwithblock 时遇到了一些问题。假设我有一个主函数

-(IBAction) callthisone {

  // Call another function "slave" here and store returned value in result

    result = return value from slave
    NSLog(@" result is %@",result);
 }];

}

-(NSArray *) slave {

 [operationQueue addOperationWithBlock: ^{   

  NSString * result = @"5" ;
  }];

 return result;
}

我永远无法获得master中返回的结果值。我该怎么做呢 ？我的做法正确吗？谢谢

Answer 1

你可以尝试这样的事情:

-(IBAction) callthisone {
    [self slave: ^(NSString* result) {
            NSLog(@" result is %@",result);
        }
    ];
}


-(void)slave: (void(^)(NSString*)) callback {
    [operationQueue addOperationWithBlock: ^{
            NSString* str = [NSString stringWithFormat: @"5]";
            callback(str);
        }
    ];
}