title: why button in view inactive with parent view's controller?
body: <p>I am using <a href="https://github.com/nicklockwood/SwipeView" rel="nofollow noreferrer">swipView</a> to make a page scrolling app</p>
  
  <p>according to  its <code>SwipeViewDataSource</code> protocol, I make a method </p>
  
  <pre><code> - (UIView *)swipeView:(SwipeView *)swipeView viewForItemAtIndex:(NSInteger)index reusingView:(UIView *)view
  {
  
          ContentViewController *contentVC = [[ContentViewController alloc]init];
          view = contentVC.view;
          return view;
  }
  </code></pre>
  
  <p>to provide the swipping content</p>
  
  <p>and the <code>ContentViewController</code> is simple enough:</p>
  
  <p>It only has this two custom methods:</p>
  
  <pre><code>- (void)viewDidLoad {
      [super viewDidLoad];
  
      UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(50, 50, 100, 200)];
      [btn setTitle:@"click me" forState:UIControlStateNormal];
      [btn setBackgroundColor:[UIColor redColor]];
      [btn addTarget:self action:@selector(onClick:) forControlEvents:UIControlEventTouchUpInside];
      [self.view addSubview:btn];
  
  }
  -(void) onClick:(id) sender {
      NSLog(@"click detected in contentView controller");
  }
  </code></pre>
  
  <p>only added a  button in <code>viewDidLoad</code> and the click listen method</p>
  
  <p>when running the app, the button showed, but click on don't fire the <code>OnClick:</code> method.</p>
  
  <p>After figuring around, I notice that if I put this method </p>
  
  <pre><code>-(void) onClick:(id)sender {
      NSLog(@"on click detected  main view controller");
  }
  </code></pre>
  
  <p>To the view which implements the <code>SwipeViewDataSource</code> ie in the "parent" which init the <code>ContentViewController</code> that line of debug info will be printed.</p>
  
  <p>It's very weird, to me. I mean why that happens?</p>