How to make iOS callback functions?

callback, ios, objective-c

Solution

1.You can do it with blocks!

You can pass some block to BottomView.

2. Or you can do it with target-action.

you can pass to BottomView selector `@selector(myMethod:)` as action, and pointer to the view controller as target. And after animation ends use `performeSelector:` method.

3. Or you can define delegate @protocol and implement methods in your viewController, and add delegate property in BottomView. @property (assign) id delegate;

If you make some animations in your BottomView, you can use UIView method

animateWithDuration:delay:options:animations:completion:

that uses blocks as callbacks

[UIView animateWithDuration:1.0f animations:^{

    }];

update:

in ButtomView.h

@class BottomView;

@protocol BottomViewDelegate <NSObject>

- (void)bottomViewAnimationDone:(BottomView *) bottomView;

@end


@interface BottomView : UIView

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

.....
@end 

in ButtomView.m

- (void)notifyDelegateAboutAnimationDone {
   if ([self.delegate respondsToSelector:@selector(bottomViewAnimationDone:)]) {
      [self.delegate bottomViewAnimationDone:self];
   }
}

and after animation complit you should call `[self notifyDelegateAboutAnimationDone];`

you should set you ViewController class to confirm to protocol BottomViewDelegate

in MyViewController.h

  @interface MyViewController : UIViewController <BottomViewDelegate>
...
@end

and f.e. in `viewDidLoad` you should set `bottomView.delegate = self;`

Problem

I can't figure out how to make a function, that will give information to the parent object, that has done something, so I need your help. Example what I want to make: - `ViewController` class instantiate class `BottomView` and adds it as it's subview. - Make a call on instance of `BottomView` class to start animate something. - After the animation ends, I want to give a sign that the animation has ended to the `ViewController` class, that it could release/remove an instance `BottomView` from itself. I need something like a callback. Could you help please?

Original source

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