UIViewController介绍：4-控制器切换（使用代码）

1、切换控制器

通过代码切换控制器的时候，需要首先创建一个目标控制器对象（创建方法参考UIViewController介绍：1-创建控制器），然后再使用presentViewController方法。

- (void)presentViewController:(UIViewController *)viewControllerToPresent animated: (BOOL)flag completion:(void (^ __nullable)(void))completion NS_AVAILABLE_IOS(5_0);

示例代码：

- (IBAction)changeVC:(id)sender {

UIStoryboard *storyBoard = [UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]];
ViewController2 *VC2 = [storyBoard instantiateViewControllerWithIdentifier:@"SecondVC"];

[self presentViewController:VC2 animated:YES completion:nil];

NSLog(@"src VC: %@, desc VC:%@", self, VC2);

}

2、返回原控制器

当需要返回原控制器时，调用dismissViewControllerAnimated:方法，此时该控制器对象会被销毁。

// The completion handler, if provided, will be invoked after the dismissed controller's viewDidDisappear: callback is invoked.
- (void)dismissViewControllerAnimated: (BOOL)flag completion: (void (^ __nullable)(void))completion NS_AVAILABLE_IOS(5_0);