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一：效果

二：项目代码

这个Demo用的几个控制器分别画了不通的xib，随便拖拽了几个空间，主要是几个按钮的切换，主要代码展示下：

//

//  NYViewController.m

//  控制器的view的显示

//

//  Created by apple on 14-10-10.

//  Copyright (c) 2014年 heima. All rights reserved.

//

#import "NYViewController.h"

#import "NYTestViewController.h"

#import "NYOneViewController.h"

#import "NYTwoViewController.h"

#import "NYThreeViewController.h"

@interface NYViewController ()

- (IBAction)vc1;

- (IBAction)vc2;

- (IBAction)vc3;

@property (nonatomic, strong) NYTestViewController *test;

@property (nonatomic, strong) NYOneViewController *one;

@property (nonatomic, strong) NYTwoViewController *two;

@property (nonatomic, strong) NYThreeViewController *three;

@end

@implementation NYViewController

- (NYOneViewController *)one

{

    if (!_one) {

        self.one = [[NYOneViewController alloc] init];

        self.one.view.frame = CGRectMake(10, 70, 300, 300);

    }

    return _one;

}

- (NYTwoViewController *)two

{

    if (!_two) {

        self.two = [[NYTwoViewController alloc] init];

        self.two.view.frame = CGRectMake(10, 70, 300, 300);

    }

    return _two;

}

- (NYThreeViewController *)three

{

    if (!_three) {

        self.three = [[NYThreeViewController alloc] init];

        self.three.view.frame = CGRectMake(10, 70, 300, 300);

    }

    return _three;

}

/**

 * 即将旋转到某个屏幕时调用

 */

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration

{

    NSLog(@"NYViewController---willRotateToInterfaceOrientation");

}

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation

{

    NSLog(@"NYViewController---didRotateFromInterfaceOrientation");

}

- (void)viewDidLoad

{

    [super viewDidLoad];

//    NYTestViewController *test = [[NYTestViewController alloc] init];

//    test.view.frame = CGRectMake(100, 100, 200, 300);

//    test.view.backgroundColor = [UIColor redColor];

//    [self.view addSubview:test.view];

//    self.test = test;

    // 如果发现：控制器的view还在，但是view上面的数据不显示，极大可能是因为：控制器被提前销毁了

    // 1.一个控制器的view是可以随意调整尺寸和位置的

    // 2.一个控制器的view是可以随意添加到其他view中

    // 3.如果将一个控制器的view，添加到其他view中显示，那么要想办法保证控制器不被销毁

    // 4.原则：只要view在，view所在的控制器必须得在，这样才能保证view内部的数据和业务逻辑正常

}

- (IBAction)vc1 {

    [self.two.view removeFromSuperview];

    [self.three.view removeFromSuperview];

    [self.view addSubview:self.one.view];

}

- (IBAction)vc2 {

    [self.one.view removeFromSuperview];

    [self.three.view removeFromSuperview];

    [self.view addSubview:self.two.view];

}

- (IBAction)vc3 {

    [self.two.view removeFromSuperview];

    [self.one.view removeFromSuperview];

    [self.view addSubview:self.three.view];

}

@end

三：旋转事件问题

这样貌似就可以完成大多数的需求了，但是有时候我们会发现一些问题，比如当屏幕旋转的时候事件无法传递

/**

 * 即将旋转到某个屏幕时调用

 */

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration

{

    NSLog(@"NYViewController---willRotateToInterfaceOrientation");

}

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation

{

    NSLog(@"NYViewController---didRotateFromInterfaceOrientation");

}

如果我们将这两个方法写到one two three这三个控制器中，相应的在屏幕旋转的时候，只有主控制器打印了这个方法，然而其他的控制器中并没有，这里的原因就是他们的控制器是平级的，虽然view是父子关系，解决办法就是设置controller的父子关系。

四：解决代码

当控制器的view互为父子关系，那么控制器最好也互为父子关系

  NYOneViewController *one = [[NYOneViewController alloc]init];

让one控制器成为当前self（HWViewController）的子控制器

    [self addChildViewController:one];

通过关addChildViewController添加一个子控制器，那么这个控制器就会被放到childViewControllers数组中
只要self在，childViewControllers数组就在数组里面的子控制器就在

//

//  NYViewController.m

//  控制器的view的显示

//

//  Created by apple on 14-10-10.

//  Copyright (c) 2014年 heima. All rights reserved.

//

#import "NYViewController.h"

#import "NYTestViewController.h"

#import "NYOneViewController.h"

#import "NYTwoViewController.h"

#import "NYThreeViewController.h"

@interface NYViewController ()

- (IBAction)vc1;

- (IBAction)vc2;

- (IBAction)vc3;

@property (nonatomic, strong) NYTestViewController *test;

@end

@implementation NYViewController

/**

 * 即将旋转到某个屏幕时调用

 */

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration

{

    NSLog(@"NYViewController---willRotateToInterfaceOrientation");

}

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation

{

    NSLog(@"NYViewController---didRotateFromInterfaceOrientation");

}

- (void)viewDidLoad

{

    [super viewDidLoad];

    //当控制器的view互为父子关系，那么控制器最好也互为父子关系

    NYOneViewController *one = [[NYOneViewController alloc]init];

    //让one控制器成为当前self（HWViewController）的子控制器

    [self addChildViewController:one];

    //通过关addChildViewController添加一个子控制器，那么这个控制器就会被放到childViewControllers数组中

    //只要self在，childViewControllers数组就在数组里面的子控制器就在

    NYTwoViewController *two = [[NYTwoViewController alloc]init];

    [self addChildViewController:two];

    NYThreeViewController *three = [[NYThreeViewController alloc]init];

    [self addChildViewController:three];

}

- (IBAction)vc1 {

    NYOneViewController *one = self.childViewControllers[0];

    NYTwoViewController *two = self.childViewControllers[1];

    NYThreeViewController *three = self.childViewControllers[2];

    [two.view removeFromSuperview];

    [three.view removeFromSuperview];

    [self.view addSubview:one.view];

}

- (IBAction)vc2 {

    NYOneViewController *one = self.childViewControllers[0];

    NYTwoViewController *two = self.childViewControllers[1];

    NYThreeViewController *three = self.childViewControllers[2];

    [one.view removeFromSuperview];

    [three.view removeFromSuperview];

    [self.view addSubview:two.view];

}

- (IBAction)vc3 {

    NYOneViewController *one = self.childViewControllers[0];

    NYTwoViewController *two = self.childViewControllers[1];

    NYThreeViewController *three = self.childViewControllers[2];

    [two.view removeFromSuperview];

    [one.view removeFromSuperview];

    [self.view addSubview:three.view];

}

@end