ios - 使用 isKindOfClass : I don't understand why this code is behaving this way

Question

-(void)viewWillAppear:(BOOL)animated
{
   [super viewWillAppear:animated];
   UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];
   imageView.image = [UIImage imageNamed:@"Sample.png"];
   [self.view addSubview:imageView];
   NSArray *subviews = [self.view subviews];
   for(id element in subviews) {
      if ([[element class] isKindOfClass:[UIImageView class]]) //check if the object is a UIImageView
      {
         NSLog(@"element is a UIImageView\n");
         [element setCenter:CGPointMake(500., 500.)];
      } else {
         NSLog(@"element is NOT a UIImageView\n");
      }
   }
}

我希望输出是“element is a UIImageView, but it's actually element is NOT a UIImageView. 为什么？不是有其他 subview 。只有一个。此外，运行时，图像显示在 100,100 ，而不是预期的 500,500。

Answer 1

您的支票有误。您应该在对象而不是对象类上调用 isKindOfClass:。

[element isKindOfClass:[UIImageView class]]