关于模态到控制器present

模态是push之后有一种 跳转到另外一个控制器的方式

1.模态 到 另一个控制器的的方法

[self presentViewController:<#(nonnull UIViewController *)#> animated:<#(BOOL)#> completion:<#^(void)completion#>]]

2.退出模态的方法

[self dismissViewControllerAnimated:<#(BOOL)#> completion:<#^(void)completion#>].

3.模态的原理

• 模态时，会把窗口上面的View给移除，把要 模态（modal）进来的控制器的View添加到窗口(window)上
• 下面模仿一下
• （1）假设有2个控制器 OneVC, TwoVC,窗口的Window的rootViewContoller是OneVC，
  - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
  self.window.rootViewController = [[OneVC alloc] init];
  [self.window makeKeyAndVisible];
  return YES
  }
• (2)OneVC实现
  - (void)viewDidLoad {
  [super viewDidLoad];
  self.view.backgroundColor = [UIColor redColor];
  UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];
  button.backgroundColor = [UIColor orangeColor];
  [button addTarget:self action:@selector(handle) forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:button];
  }
  按钮方法实现--模态
  TwoVC *twoVC = [[TwoVC alloc] init];
  CGRect frame = twoVC.view.frame;
  frame.origin.y = [UIScreen mainScreen].bounds.size.height;
  twoVC.view.frame = frame;
  [[UIApplication sharedApplication].keyWindow addSubview:twoVC.view];
  self.twoVC = twoVC；
  [UIView animateWithDuration:0.5 animations:^{
  twoVC.view.frame = self.view.frame;
  }completion:^(BOOL finished) {
  [self.view removeFromSuperview];
  }];