iOS开发_返回页面时使用dismiss还是pop？

方法一：通过ViewController的属性presentingViewController判断当前页面是否是被present出的，来确定采用dismiss方法

• (void)backAction
  {
  if (self.presentingViewController)
  {
  [self dismissViewControllerAnimated:YES completion:nil];
  }
  else
  {
  [self.navigationController popViewControllerAnimated:YES];
  }
  方法二：通过NavgationController的属性topViewController判断当前页面是否是被push出的最上层页面，来确定采用pop方法
• (void)backAction
  {
  if (self.navigationController.topViewController == self)
  {
  [self.navigationController popViewControllerAnimated:YES];
  }
  else
  {
  [self dismissViewControllerAnimated:YES completion:nil];
  }
  }
  方法三：通过NavgationController的属性viewcontrollers数组索引，来判断当前页面是否是被push过，来确定采用dismiss方法
• (void)backAction
  {
  if ([self.navigationController.viewControllers.firstObject isEqual:self])
  {//当前页面尚未被Push过
  [self dismissViewControllerAnimated:YES completion:nil];
  }
  else
  {
  [self.navigationController popViewControllerAnimated:YES];
  }
  }