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This was nice and fast... but it takes up WAY TOO MUCH space. And it's annoying to write.
(I like the way I can just step into the function that calls the delegate for debugging)
What's a better way to not make me call respondsToSelector in the middle of my code? Some proxy?
struct {
unsigned int delegateWillDisplayDocument:1;
unsigned int delegateDidDisplayDocument:1;
unsigned int delegateDidShowPageView:1;
unsigned int delegateDidRenderPageView:1;
unsigned int delegateDidChangeViewMode:1;
unsigned int delegateDidTapOnPageView:1;
unsigned int delegateDidTapOnAnnotation:1;
unsigned int delegateShouldDisplayAnnotation:1;
unsigned int delegateViewForAnnotation:1;
unsigned int delegateAnnotationViewForAnnotation:1;
unsigned int delegateWillShowAnnotationView:1;
unsigned int delegateDidShowAnnotationView:1;
unsigned int delegateDidLoadPageView:1;
unsigned int delegateWillUnloadPageView:1;
unsigned int delegateDidEndPageScrollingAnimation:1;
unsigned int delegateDidEndZoomingAtScale:1;
unsigned int delegateWillShowControllerAnimated:1;
unsigned int delegateDidShowControllerAnimated:1;
} delegateFlags_;
- (void)setDelegate:(id<PSPDFViewControllerDelegate>)delegate {
if (delegate != delegate_) {
delegate_ = delegate;
delegateFlags_.delegateWillDisplayDocument = [delegate respondsToSelector:@selector(pdfViewController:willDisplayDocument:)];
delegateFlags_.delegateDidDisplayDocument = [delegate respondsToSelector:@selector(pdfViewController:didDisplayDocument:)];
delegateFlags_.delegateDidShowPageView = [delegate respondsToSelector:@selector(pdfViewController:didShowPageView:)];
delegateFlags_.delegateDidRenderPageView = [delegate respondsToSelector:@selector(pdfViewController:didRenderPageView:)];
delegateFlags_.delegateDidChangeViewMode = [delegate respondsToSelector:@selector(pdfViewController:didChangeViewMode:)];
delegateFlags_.delegateDidTapOnPageView = [delegate respondsToSelector:@selector(pdfViewController:didTapOnPageView:info:coordinates:)];
delegateFlags_.delegateDidTapOnAnnotation = [delegate respondsToSelector:@selector(pdfViewController:didTapOnAnnotation:page:info:coordinates:)];
delegateFlags_.delegateShouldDisplayAnnotation = [delegate respondsToSelector:@selector(pdfViewController:shouldDisplayAnnotation:onPageView:)];
delegateFlags_.delegateViewForAnnotation = [delegate respondsToSelector:@selector(pdfViewController:viewForAnnotation:onPageView:)];
delegateFlags_.delegateAnnotationViewForAnnotation = [delegate respondsToSelector:@selector(pdfViewController:annotationView:forAnnotation:onPageView:)];
delegateFlags_.delegateWillShowAnnotationView = [delegate respondsToSelector:@selector(pdfViewController:willShowAnnotationView:onPageView:)];
delegateFlags_.delegateDidShowAnnotationView = [delegate respondsToSelector:@selector(pdfViewController:didShowAnnotationView:onPageView:)];
delegateFlags_.delegateDidLoadPageView = [delegate respondsToSelector:@selector(pdfViewController:didLoadPageView:)];
delegateFlags_.delegateWillUnloadPageView = [delegate respondsToSelector:@selector(pdfViewController:willUnloadPageView:)];
delegateFlags_.delegateDidEndPageScrollingAnimation = [delegate respondsToSelector:@selector(pdfViewController:didEndPageScrollingAnimation:)];
delegateFlags_.delegateDidEndZoomingAtScale = [delegate respondsToSelector:@selector(pdfViewController:didEndPageZooming:atScale:)];
delegateFlags_.delegateWillShowControllerAnimated = [delegate respondsToSelector:@selector(pdfViewController:willShowController:embeddedInController:animated:)];
delegateFlags_.delegateDidShowControllerAnimated = [delegate respondsToSelector:@selector(pdfViewController:didShowController:embeddedInController:animated:)];
}
}
- (void)delegateWillDisplayDocument {
if (delegateFlags_.delegateWillDisplayDocument) {
[self.delegate pdfViewController:self willDisplayDocument:self.document];
}
}
- (void)delegateDidDisplayDocument {
if(delegateFlags_.delegateDidDisplayDocument) {
[self.delegate pdfViewController:self didDisplayDocument:self.document];
}
}
(etc, etc)
@macguru
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macguru commented Jun 5, 2012

I prefer to check the respondsToSelector in place. Generally rather dislike such caches. I usually don't have that much delegate methods though...

However, you could build a proxy class that assembles method implementations automatically using runtime calls. That'd be extremely elegant, albeit a bit of work and probably shooting with canons on pigeons. You could open-source it afterwards though ;)

@hatfinch
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hatfinch commented Aug 1, 2012

No proxy tricks, but FWIW I use ids directly:

struct
{
    id willDisplayDocumentDelegate;
    id didDisplayDocumentDelegate;
    // etc.
} _delegates;

- (void)setDelegate:(id <PSPDFViewControllerDelegate>)delegate
{
    if (delegate)
    {
        if ([delegate respondsToSelector:@selector(pdfViewController:willDisplayDocument:)])
            _delegates.willDisplayDocumentDelegate = delegate;

        if ([delegate respondsToSelector:@selector(pdfViewController:didDisplayDocument:)])
            _delegates.didDisplayDocumentDelegate = delegate;

        // etc.
    }
    else
        memset(_delegates, 0, sizeof(_delegates));
}

- (void)delegateWillDisplayDocument
{
    [_delegates.willDisplayDocumentDelegate pdfViewController:self willDisplayDocument:self.document];
}

- (void)delegateDidDisplayDocument
{
    [delegates_.didDisplayDocumentDelegate pdfViewController:self didDisplayDocument:self.document];
}

// etc.

@MichaelHackett
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MichaelHackett commented Mar 11, 2014

I like your approach, @hatfinch, but should the zeroing of the _delegates table not should happen first, and unconditionally, as the if statements only set the fields for methods that are present in the new delegate. If there was a previous setting for a field and the new delegate doesn't implement that method, the old value would still be present (causing the old delegate to be called for some methods).

Also, I believe that object refs in a struct are no longer allowed under ARC, but (__weak) ivars could work just as well.

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