iOS -- childViewController 的问题

做开发,会经常碰到图片这种类似的需求.或是segmentControl 或者两个button控制两个界面直接的切换

推荐一个比较好用的方法

新建两个viewController,我们命名为FirstViewController 和 SecondViewController

在RootViewController的代码如下

#import "RootViewController.h"
#import "FirstViewController.h"
#import "SecondTableViewController.h"

@interface RootViewController ()<UIScrollViewDelegate>

@property (nonatomic, strong) UISegmentedControl *segmentedControl;
@property (nonatomic, strong) UIScrollView *scrollView;
@property (nonatomic, strong) FirstViewController *firstVC;
@property (nonatomic, strong) SecondTableViewController *secondTVC;

@end

@implementation RootViewController

- (void)viewDidLoad
{
[super viewDidLoad];

// 适应scrollView
self.automaticallyAdjustsScrollViewInsets = NO;

self.segmentedControl = [[UISegmentedControl alloc] initWithItems:@[@"first", @"second"]];
self.navigationItem.titleView = self.segmentedControl;
[self.segmentedControl addTarget:self action:@selector(segmentedControlAction:) forControlEvents:UIControlEventValueChanged];
self.segmentedControl.selectedSegmentIndex = 0;

// 创建scrollView
self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 64, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height - 64)];
[self.view addSubview:self.scrollView];
// 设置scrollView的内容
self.scrollView.contentSize = CGSizeMake([UIScreen mainScreen].bounds.size.width * 2, [UIScreen mainScreen].bounds.size.height - 64);
self.scrollView.pagingEnabled = YES;
self.scrollView.bounces = NO;

// 创建控制器
self.firstVC = [FirstViewController new];
self.secondTVC = [[SecondTableViewController alloc] initWithStyle:UITableViewStylePlain];
// 添加为self的子控制器
[self addChildViewController:self.firstVC];
[self addChildViewController:self.secondTVC];
self.firstVC.view.frame = CGRectMake(0, 0, self.scrollView.frame.size.width, CGRectGetHeight(self.scrollView.frame));
self.secondTVC.view.frame = CGRectMake([UIScreen mainScreen].bounds.size.width, 0, self.scrollView.frame.size.width, CGRectGetHeight(self.scrollView.frame));
[self.scrollView addSubview:self.firstVC.view];
[self.scrollView addSubview:self.secondTVC.view];

// 设置scrollView的代理
self.scrollView.delegate = self;
}

这里的要点就是我们在RootViewController上添加两个子视图FirstViewController 和 SecondViewController

// 添加为self的子控制器
[self addChildViewController:self.firstVC];
[self addChildViewController:self.secondTVC];

这样写的好处是将两个页面完全与RootViewController完全独立开来,各自处理各自的数据与页面内容.

碰到类似的情况了,都可以用viewController作为childViewController去添加.比起添加自定义的UIView方便一点

比如页面跳转,我们点击firstViewController的时候,就可以用

[self.parentViewController.navigationController pushViewController:<#(nonnull UIViewController *)#> animated:YES];

直接调用父视图的navigationController跳转.

/**
* 分段控制器点击方法
*/
- (void)segmentedControlAction:(UISegmentedControl *)sender
{
[self.scrollView setContentOffset:CGPointMake(sender.selectedSegmentIndex * self.scrollView.frame.size.width, 0) animated:NO];
}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
NSInteger n = scrollView.contentOffset.x / scrollView.frame.size.width;
self.segmentedControl.selectedSegmentIndex = n;
}