objective-c - objective-c :按下按钮后切换属性的BOOLEAN值的问题

Question

我正在尝试切换属性“isLiked”的BOOLEAN值，如以下代码所示

//BOOL isLiked is defined in the header file as property of answer class
- (void)buttonPressed
{
    NSLog(@"button pressed");

    if ([btnType isEqualToString:@"like"]) 
    {
       self.answer.isLiked = !self.answer.isLiked;  
       NSLog(@"answer is: %i",self.answer.isLiked);
   }

}

当我打印出“self.answer.isLiked”的值时，我看到返回的值始终为“0”。如何切换值？

Answer 1

我猜self.answer实际上是nil。这将导致self.answer.isLiked = !self.answer.isLiked完全不执行任何操作，并使NSLog实际记录nil的整数值，即0。