#import "BaseViewController.h"
#import "ViewController.h"
@interface BaseViewController ()
@end
@implementation BaseViewController
- (void)viewDidLoad {
[super viewDidLoad];
ViewController * v1= [[ViewController alloc]init];
ViewController * v2= [[ViewController alloc]init];
ViewController * v3= [[ViewController alloc]init];
ViewController * v4= [[ViewController alloc]init];
v1.view.backgroundColor = [UIColor redColor];
v2.view.backgroundColor = [UIColor cyanColor];
v3.view.backgroundColor = [UIColor grayColor];
v4.view.backgroundColor = [UIColor greenColor];
// 1、向视图控制器容器中添加子视图控制器
[self addChildViewController:v1];
[self addChildViewController:v2];
[self addChildViewController:v3];
[self addChildViewController:v4];
[v1.view setFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
[self.view addSubview: v1.view];
[v2.view setFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
[self.view addSubview: v2.view];
[v3.view setFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
[self.view addSubview: v3.view];
[v4.view setFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
[self.view addSubview: v4.view];
//2、交换两个子视图控制器的位置
[self transitionFromViewController:v4 toViewController:v3 duration:5 options:UIViewAnimationOptionLayoutSubviews animations:^{
v3.view.frame = CGRectMake(100, 100, 200, 200);
} completion:^(BOOL finished) {
///v4 被替换掉的视图，动画完成后，显示v3的View,V4的视图 消失
}];
//3、从父视图控制器中删除
[v2 removeFromParentViewController];//并不会移除 已经 添加在 self.view 上的 v2.view
}
