iOS-父子控制器

界面:

为什么需要使用父子控制器:

点击社会-头条-热点按钮:
    1.相应的控制器每次都需要创建
    2.相应的控制器的view每次都加上去
    3.相应的控制器不能处理业务逻辑,控制器被销毁
注:
    为什么view在,viewController不在(因为viewController被销毁所以不能处理业务逻辑)?
    1.只添加了控制器的view并没有添加控制器，控制器没有强引用被销毁

解决方案:
1.在顶层ViewController设置强引用(强烈不推荐)
2.使用父子控制器(UIViewController管理子UIViewController)

ViewController.m
- (void)viewDidLoad {
    [super viewDidLoad];
    //添加子控制器到父控制器
    // 社会
    ScoietyViewController *scoietyVc = [[ScoietyViewController alloc] init];
    scoietyVc.title = @"社会";
    [self addChildViewController:scoietyVc];

    // 头条
    TopLineViewController *topLineVc = [[TopLineViewController alloc] init];
    topLineVc.title = @"头条";
    [self addChildViewController:topLineVc];

    // 热点
    HotViewController *hotVc = [[HotViewController alloc] init];
    hotVc.title = @"热点";
    [self addChildViewController:hotVc];

    //设置按钮内容
    NSInteger count = self.titleContainView.subviews.count;
    for (int i = 0; i < count; i++) {
        UIButton *btn = self.titleContainView.subviews[i];
        //获取当前控制器对象
        UIViewController *vc = self.childViewControllers[i];
        [btn setTitle:vc.title forState:UIControlStateNormal];
    }
}


// 点击标题按钮
- (IBAction)showChildVcView:(UIButton *)sender {

    // 移除之前控制器的view
    [self.containView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
//    for (UIView *vcView in self.containView.subviews) {
//        [vcView removeFromSuperview];
//    }

    // 把对应子控制器的view添加上去
    UIViewController *vc = self.childViewControllers[sender.tag];
    vc.view.backgroundColor = sender.backgroundColor;
    vc.view.frame = self.containView.bounds;
    [self.containView addSubview:vc.view];
}

push

界面:

ViewController.m
@implementation ViewController
// UIViewController也是可以管理子控制器
- (void)viewDidLoad {
    [super viewDidLoad];

    // 添加一个子控制器
    ChildViewController *childVc = [[ChildViewController alloc] init];
    childVc.view.backgroundColor = [UIColor greenColor];
    childVc.view.frame = CGRectMake(50, 50, 200, 200);
    [self.view addSubview:childVc.view];
    [self addChildViewController:childVc];   
}
@end
ChildViewController.m
@implementation ChildViewController
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    NSLog(@"点击了子控制器的view %@",self.navigationController);
    //点击了子控制器的view <UINavigationController: 0x7f8adc029a00>

    UIViewController *vc = [[UIViewController alloc] init];
    vc.view.backgroundColor = [UIColor redColor];
    /* 获取导航控制器
    1.首先去判断下自己是否是导航控制器的子控制器,
    2.否，判断父控制器是否是导航控制器的子控制器,
    3.否，直到没有父控制器为止
    */
    [self.navigationController pushViewController:vc animated:YES];

}
@end

modal

界面:

ViewController.m
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    ModalViewController *vc = [[ModalViewController alloc] init];
    vc.view.backgroundColor = [UIColor redColor];
    [self presentViewController:vc animated:YES completion:nil];
}

ModalViewController.m
- (void)viewDidLoad {
    [super viewDidLoad];

    ChildViewController *childVc = [[ChildViewController alloc] init];
    childVc.view.backgroundColor = [UIColor blueColor];
    childVc.view.frame = CGRectMake(50, 50, 200, 200);
    [self.view addSubview:childVc.view];
    [self addChildViewController:childVc];
}

ChildViewController.m
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    NSLog(@"点击子控制器的view");
    // 判断下当前方法调用者是否被modal,
    //如果不是,判断父控制器是否被modal
    [self dismissViewControllerAnimated:YES completion:nil];
}