이미지 뷰어 위치 조정하기

출처 : http://stackoverflow.com/questions/638299/uiscrollview-with-centered-uiimageview-like-photos-app

Hokay, Here is what I'd consider, the solution as in it behaves exactly like apple's photo app. I had been using solutions that used:

-(void) scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale

to recenter but I didn't like that solution because after the zooming was done, it'd bounce then quick 'jump' into the center which was very un-sexy. Turns out if you pretty much do the exact same logic but in this delegate function:

-(void)scrollViewDidZoom:(UIScrollView *)pScrollView

it both starts off centered and when you zoom out it stays centered:

-(void)scrollViewDidZoom:(UIScrollView *)pScrollView {

CGRect innerFrame = imageView.frame;

CGRect scrollerBounds = pScrollView.bounds;


if ( ( innerFrame.size.width < scrollerBounds.size.width ) || ( innerFrame.size.height < scrollerBounds.size.height ) )

{

    CGFloat tempx = imageView.center.x - ( scrollerBounds.size.width / 2 );

    CGFloat tempy = imageView.center.y - ( scrollerBounds.size.height / 2 );

    CGPoint myScrollViewOffset = CGPointMake( tempx, tempy);


    pScrollView.contentOffset = myScrollViewOffset;


}


UIEdgeInsets anEdgeInset = { 0, 0, 0, 0};

if ( scrollerBounds.size.width > innerFrame.size.width )

{

    anEdgeInset.left = (scrollerBounds.size.width - innerFrame.size.width) / 2;

    anEdgeInset.right = -anEdgeInset.left;  // I don't know why this needs to be negative, but that's what works

}

if ( scrollerBounds.size.height > innerFrame.size.height )

{

    anEdgeInset.top = (scrollerBounds.size.height - innerFrame.size.height) / 2;

    anEdgeInset.bottom = -anEdgeInset.top;  // I don't know why this needs to be negative, but that's what works

}

pScrollView.contentInset = anEdgeInset;

}