ContainerViewController委托给ChildViewController

Question

ContainerViewController将方法-delegateMethod委托给ChildViewController。

但是在下面的代码中，不调用-delegateMethod。

我认为这是因为_childViewController已经被释放了。

如何修复它以使运行-delegateMethod

ContainerViewController.h

@protocol ContainerViewDelegate <NSObject>

- (void)delegateMethod;

@end

@interface ContainerViewController : UIViewController

@property (nonatomic, assign) id<ContainerViewDelegate> delegate;

@end

ContainerViewController.m

@interface ContainerViewController () {
    ChildViewController *_childViewController;
}

//...

- (void)viewDidLoad
{
    _childViewController = [[WeeklyViewController alloc]init];
    [self addChildViewController:_childViewController];
    [self.view addSubview:_childViewController.view];
    [_childViewController didMoveToParentViewController:self];
}

- (void)buttonAction {
    [self.delegate delegateMethod];
}

ChildViewController.m

@interface ChildViewController () <ContainerViewDelegate>

//...

- (void)delegateMethod {
    NSLog(@"succeed!");
}

Answer 1

您从不设置委托，因此self.delegate将为零。你应该这么做，

    - (void)viewDidLoad
{
    _childViewController = [[WeeklyViewController alloc]init];
    self.delegate = _childViewController;
    [self addChildViewController:_childViewController];
    [self.view addSubview:_childViewController.view];
    [_childViewController didMoveToParentViewController:self];
}