首先，确保APP支持屏幕旋转，具体怎么支持，去网上查询一下

然后，在对应的类中进行如下操作

pragma mark 转屏方法重写

-(UIInterfaceOrientationMask)supportedInterfaceOrientations {
return [self.viewControllers.lastObject supportedInterfaceOrientations];
}

• (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {
  return [self.viewControllers.lastObject preferredInterfaceOrientationForPresentation];
  }
  -(BOOL)shouldAutorotate {
  return self.visibleViewController.shouldAutorotate;
  }

最后，在你不想转屏切换的的ViewController上重写以下方法：

pragma mark 转屏方法 不允许转屏

-(UIInterfaceOrientationMask)supportedInterfaceOrientations {
return UIInterfaceOrientationMaskPortrait ;
}

• (BOOL)shouldAutorotate{
  return NO;
  }
  -(UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {
  return UIInterfaceOrientationPortrait;
  }
• (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
  return NO;
  }

在你想转屏切换的的ViewController上可以照这样重写（允许左右横屏以及竖屏）：

• (BOOL)shouldAutorotate {
  return YES;
  }
  -(UIInterfaceOrientationMask)supportedInterfaceOrientations {
  return UIInterfaceOrientationMaskAll;
  }

• (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {
  return UIInterfaceOrientationPortrait;
  }

• (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
  return YES;
  }
  另外，在的ViewController中对于转屏事件可以参见下面的方法进行捕获：

• (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
  [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];
  [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
  //计算旋转之后的宽度并赋值
  CGSize screen = [UIScreen mainScreen].bounds.size;
  //界面处理逻辑
  self.lineChartView.frame = CGRectMake(0, 30, screen.width, 200.0);
  //动画播放完成之后
  if(screen.width > screen.height ){

  NSLog(@"横屏");

  }else{
  NSLog(@"竖屏");
  }

  } completion:^(id<UIViewControllerTransitionCoordinatorContext> context) {

  NSLog(@"动画播放完之后处理");

  }];

}

区分当前屏幕是否为横竖屏的状态，其实通过判断当前屏幕的宽高来决定是不是横屏或者竖屏：

**竖屏时：

**宽<高

**横屏时：

**宽>高