Modal控制器的跳转

#import "ViewController.h"
#import "TwoViewController.h"

@interface ViewController ()

@property (nonatomic, strong) TwoViewController *twoVC;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    self.view.backgroundColor = [UIColor redColor];
}
- (IBAction)modal:(id)sender {
    
    
    
    /***
      1.modal出控制器的View是添加到哪里的?
        把之前窗口的根控制器的view,从窗口上移除.
        modal出控制器的View是添加到窗口上的
     
       2.modal出控制器要不要强引用?如果要的话, 是谁强引用?
         必须得要有人强引用.
         是有self.presentedViewController
     
       3.如果一个控制器没有强引用, 会造成什么问题?
         如果一个控制器没有强引用,那么该控制器下的所有业务逻辑都没有效果(所有写的代码都不执行了);
     */
    
//    CGFloat width = [UIScreen mainScreen].bounds.size.width;
//    CGFloat height = [UIScreen mainScreen].bounds.size.height;
//    
    TwoViewController *twoVC = [[TwoViewController alloc] init];
//    self.twoVC = twoVC;
//    twoVC.view.frame = CGRectMake(0, height, width, height);
//    [UIView animateWithDuration:0.5 animations:^{
//        CGRect frame = twoVC.view.frame;
//        frame.origin.y = 0;
//        twoVC.view.frame = frame;
//    }];
//
//    
//    [[UIApplication sharedApplication].keyWindow addSubview:twoVC.view];
    
    NSLog(@"%@",self.presentedViewController);
    [self presentViewController:twoVC animated:YES completion:^{
        //NSLog(@"%@",[UIApplication sharedApplication].keyWindow.rootViewController);
        NSLog(@"%@",self.presentedViewController);
    }];
    
    
}

- (void)dealloc {
    NSLog(@"%s",__func__);
}