无法更改自定义UIBarButton项目

Question

I am trying to add a custom bar button to my project and I'm having a few problems. First lets go over the requirement for my button, it needs:

- to display a custom font
- to be enabled/disabled
- to have its colour animated based to provide user feedback.

So I first tried connecting a barButtonItem up through the storyboard and I could change the colour and enable disable it. However I could not change the font or add colour animation to it. I want to be able to use the following method which I am already using in the app to animate the colour:

- (void)textFlashTextfieldAnimation:(nonnull UITextField *)view duration:(NSTimeInterval)duration animateToColour:(UIColor*)animationColour textColor:(UIColor*)textColour completion:(void (^)(BOOL finished))completion {
    [UIView transitionWithView:view duration:0 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
        view.textColor = animationColour;
    } completion:^(BOOL finished) {
        [UIView transitionWithView:view duration:2.0f options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
            view.textColor = textColour;
        } completion:completion];
    }];
} 

Ideally I would be able to change this function to accept a barButtonItem / UIButton so that I could animate it easily. However if I connect the button up through storyboards I cannot access the button's layer so the animation is not possible.

I had started to go about this through code but I've gone down 2 dead ends. Here is a really basic implementation of a barButtonItem :

UIBarButtonItem *myButton=[[UIBarButtonItem alloc] initWithTitle:@"My Custom Button" style:UIBarButtonItemStylePlain target:self action:@selector(/*do something*/)];
    [self.navigationItem setRightBarButtonItem:myButton];

Now this will work in the fact that I can use it like a storyboard button however I cannot alter the font or access the button's layer so it is also no good.

I then tried creating a fully custom view for my bar button by creating a UIView and a UIButton and then adding them to a barButtonItem , this can be seen here:

UIFont *barButtonFonts = [UIFont fontWithName:kFont size:16];

    //Right Button
    //create view
    UIView *rightButtonView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 45, 25)];

    //create button
    UIButton *rightButton = [UIButton buttonWithType:UIButtonTypeSystem];
    rightButton.backgroundColor = [UIColor clearColor];
    rightButton.frame = rightButtonView.frame; //set frame = to view
    [rightButton setTitle:NSLocalizedString(@"Save", nil) forState:UIControlStateNormal];
    rightButton.titleLabel.font = barButtonFonts;

    rightButton.tintColor = [UIColor redColor];

    [rightButton addTarget:self action:@selector(actionMethod) forControlEvents:UIControlEventTouchUpInside];

    [rightButtonView addSubview:rightButton];

    UIBarButtonItem *rightBarButton = [[UIBarButtonItem alloc] initWithCustomView:rightButtonView];

    self.navigationItem.rightBarButtonItem = rightBarButton;

Now I have a barButtonItem that will display a custom font however it is has no UI interaction at all. It looks the same when enabled/disabled and when not-highlighted/highlighted. The button works as it should it just doesn't look like it should.

Should I create an outlet to this button somewhere in my code so that I can alter the button when in the view? Is it even possible to alter a button after it has been added to the navigation bar?

If anybody has any suggestions it would be appreciated!

Answer 1

Yeah barbuttonitem isn't modifieable after you added it to the bar. only way i can think is to remove the button and add a new one (with the new characteristics) when user interact with it. I suggest you to use a custom toolbar (like a normal UIView), then add a normal button to it. it would be easier to customize