IOS开发—通过ChildViewController实现view的切换

ChildViewController的应用

viewControlle中可以添加多个subView，在需要的时候显示出来；另一种方法是通过向parentViewController中可以添加多个childCiewController;来控制页面中的subView，降低代码耦合度；通过切换子视图控制器，可以显示不同的view；，替代之前的addSubView的管理。

本节通过类似百度新闻模块切换的界面来演示ChileViewController的应用：

文档结构：

代码演示：

#import "MainViewController.h"#import "FirstViewController.h"#import "SecondViewController.h"#import "ThirdViewController.h"@interface MainViewController ()@property (nonatomic, strong) FirstViewController *firstVC;@property (nonatomic, strong) SecondViewController *secondVC;@property (nonatomic, strong) ThirdViewController *thirdVC;@property (nonatomic, strong) UIViewController *currentVC; @property (nonatomic, strong) UIScrollView *headScrollView;@property (nonatomic, strong) NSMutableArray *itemArray;@property (nonatomic, strong) UIView *contentView;@end @implementation MainViewController- (void)loadView{    [super loadView];    [self initialization];} - (void)viewDidLoad {    [super viewDidLoad];    [self loadBaseUI];} - (void)initialization{    _itemArray = [NSMutableArray arrayWithObjects:@"头条",@"今日",@"焦点", nil];} - (void)loadBaseUI{    self.title = @"首页";    _headScrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, 44)];    _headScrollView.backgroundColor = [UIColor colorWithWhite:0.902 alpha:1.000];    for (int i = 0; i<_itemArray.count; i++) {        UIButton *itemButton = [[UIButton alloc]initWithFrame:CGRectMake(i*([UIScreen mainScreen].bounds.size.width/_itemArray.count), 0, [UIScreen mainScreen].bounds.size.width/_itemArray.count, 44)];        itemButton.tag = 100+i;        itemButton.backgroundColor = [UIColor clearColor];        NSDictionary *dic = @{NSForegroundColorAttributeName:[UIColor purpleColor],NSFontAttributeName:[UIFont systemFontOfSize:14.0f]};        [itemButton setAttributedTitle:[[NSAttributedString alloc]initWithString:_itemArray[i] attributes:dic] forState:UIControlStateNormal];        [itemButton addTarget:self action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];        [_headScrollView addSubview:itemButton];    }    [_headScrollView setContentSize:CGSizeMake([UIScreen mainScreen].bounds.size.width, 44)];    _headScrollView.showsHorizontalScrollIndicator = NO;    _headScrollView.showsVerticalScrollIndicator = NO;    [self.view addSubview:_headScrollView];       _contentView = [[UIView alloc]initWithFrame:CGRectMake(0, 44, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height - 44 - 64)];    _contentView.backgroundColor = [UIColor clearColor];    [self.view addSubview:_contentView];       [self addSubControllers];} #pragma mark - privatemethods- (void)addSubControllers{    _firstVC = [[FirstViewController alloc]initWithNibName:@"FirstViewController" bundle:nil];    [self addChildViewController:_firstVC];       _secondVC = [[SecondViewController alloc]initWithNibName:@"SecondViewController" bundle:nil];    [self addChildViewController:_secondVC];       _thirdVC = [[ThirdViewController alloc]initWithNibName:@"ThirdViewController" bundle:nil];    [self addChildViewController:_thirdVC];     //调整子视图控制器的Frame已适应容器View    [self fitFrameForChildViewController:_firstVC];    //设置默认显示在容器View的内容    [self.contentView addSubview:_firstVC.view];       NSLog(@"%@",NSStringFromCGRect(self.contentView.frame));    NSLog(@"%@",NSStringFromCGRect(_firstVC.view.frame));       _currentVC = _firstVC;} - (void)buttonClick:(UIButton *)sender{    if ((sender.tag == 100 && _currentVC == _firstVC) || (sender.tag == 101 && _currentVC == _secondVC) || (sender.tag == 102 && _currentVC == _thirdVC)) {        return;    }    switch (sender.tag) {        case 100:{            [self fitFrameForChildViewController:_firstVC];            [self transitionFromOldViewController:_currentVC toNewViewController:_firstVC];        }            break;        case 101:{            [self fitFrameForChildViewController:_secondVC];            [self transitionFromOldViewController:_currentVC toNewViewController:_secondVC];        }            break;        case 102:{            [self fitFrameForChildViewController:_thirdVC];            [self transitionFromOldViewController:_currentVC toNewViewController:_thirdVC];        }            break;    }} - (void)fitFrameForChildViewController:(UIViewController *)chileViewController{    CGRect frame = self.contentView.frame;    frame.origin.y = 0;    chileViewController.view.frame = frame;} //转换子视图控制器- (void)transitionFromOldViewController:(UIViewController *)oldViewControllertoNewViewController:(UIViewController *)newViewController{    [self transitionFromViewController:oldViewController toViewController:newViewController duration:0.3 options:UIViewAnimationOptionTransitionCrossDissolve animations:nil completion:^(BOOL finished) {        if (finished) {            [newViewController didMoveToParentViewController:self];            _currentVC = newViewController;        }else{            _currentVC = oldViewController;        }    }];} //移除所有子视图控制器- (void)removeAllChildViewControllers{    for (UIViewController *vc in self.childViewControllers) {        [vc willMoveToParentViewController:nil];        [vc removeFromParentViewController];    }} /** *  方法说明： *  1、addChildViewController:向父VC中添加子VC，添加之后自动调用willMoveToParentViewController:父VC *  2、removeFromParentViewController:将子VC从父VC中移除，移除之后自动调用    didMoveToParentViewController:nil *  3、willMoveToParentViewController:  当向父VC添加子VC之后，该方法会自动调用。若要从父VC移除子VC，需要在移除之前调用该方法，传入参数nil。 *  4、didMoveToParentViewController:  当向父VC添加子VC之后，该方法不会被自动调用，需要显示调用告诉编译器已经完成添加（事实上不调用该方法也不会有问题，不太明白）; 从父VC移除子VC之后，该方法会自动调用，传入的参数为nil,所以不需要显示调用。 */ /** *  注意点：    要想切换子视图控制器a/b,a/b必须均已添加到父视图控制器中，不然会报错 */@end

最终效果：(实现了3个视图之间的切换)