如何在 iPhone 的 uiscrollview 内的 uiimageview 中实现捏合捏合？

Question

Hello I have implemented photoslide show using apple's scrolling example.Below is code:

- (void)viewDidLoad {

    appDelegate=[(FoodAppDelegate *)[UIApplicationsharedApplication]delegate];
    kNumImages=[parray count];
    self.view.backgroundColor=[UIColor viewFlipsideBackgroundColor];
    [scrollView1 setBackgroundColor:[UIColor blackColor]];
    [scrollView1 setCanCancelContentTouches:NO];
    scrollView1.indicatorStyle=UIScrollViewIndicatorStyleWhite;
    scrollView1.clipsToBounds=YES;
    scrollView1.scrollEnabled=YES;   
        scrollView1.pagingEnabled=YES;
    scrollView1.minimumZoomScale=0.5;
    scrollView1.delegate=self;
    scrollView1.maximumZoomScale=6.0;
    scrollView1.bouncesZoom=YES;
    NSLog(@"view did load called");
    NSUInteger i;
    for(i=0;i<kNumImages;i++)
    {
        NSLog(@"for loop of view did load called");
        NSURL *url=[NSURL URLWithString:[parray objectAtIndex:i]];
        NSLog(@"url object at index %i is %@",i,url);
        UIImage *image=[UIImage imageWithData:[NSData dataWithContentsOfURL:url]];
        imageView=[[UIImageView alloc] initWithImage:image];
        CGRect rect=imageView.frame;
        rect.size.height=kScrollObjHeight;
        rect.size.width=kScrollObjWidth;
        imageView.frame=rect;
        imageView.tag=i+1;
        [scrollView1 addSubview:imageView];

    }
    [scrollView1 setContentSize:CGSizeMake(imageView.frame.size.width, imageView.frame.size.height)];
    [self layoutScrollImages];
    [super viewDidLoad];
}



-(void)layoutScrollImages
{
    int c=appDelegate.selectedphoto-1;
    kNumImages=[parray count];
    view=nil;
    NSArray *subviews=[scrollView1 subviews];
    CGFloat curXLoc=0;
    for(view in subviews)
    {
        if([view isKindOfClass:[UIImageView class]] && view.tag>0)
        {
            CGRect frame=view.frame;
            frame.origin=CGPointMake(curXLoc, 0);
            view.frame=frame;
            curXLoc+=(kScrollObjWidth);
        }}
    [scrollView1 setContentSize:CGSizeMake((kNumImages *kScrollObjWidth),200)];
    CGPoint lastFrame = CGPointMake(( c* kScrollObjWidth), 0.0f);
    [scrollView1 setContentOffset:lastFrame];
    scrollView1.showsHorizontalScrollIndicator=NO;
    scrollView1.showsVerticalScrollIndicator=NO;

}

Now i want to implement zoom in zoom out.How can i do that?any sample code or example?

Answer 1

create a uiscrollview within a uiscrollview with a uiimageview within that. the outer uiscrollview scrolls horizontally and the inner one is set up for pinch and zoom. IOS is actually smart enough to engage the parent uiscrollview when the inner scroller is totally zoomed out or is at the edge.

Many examples are out there to create a pinch/zoom app uiscrollview.

scrollView=[[UIScrollView alloc] initWithFrame:[BFCoords sharedBFCoords].APP_RECT];
scrollView.scrollEnabled=YES;
scrollView.maximumZoomScale=1;
scrollView.minimumZoomScale=.5;
scrollView.delegate=self;
scrollView.clipsToBounds=YES;



contentView=[[UIView alloc] initWithFrame:CGRectMake(0, 0, [BFCoords sharedBFCoords].APP_WIDTH*2, [BFCoords sharedBFCoords].APP_HEIGHT*2)];
scrollView.contentSize=CGSizeMake([BFCoords sharedBFCoords].APP_WIDTH*2, [BFCoords sharedBFCoords].APP_HEIGHT*2);

[scrollView addSubview:contentView];

[self addSubview:scrollView];

scrollView.zoomScale=.5;
[scrollView setBackgroundColor:[UIColor blueColor]];
self.hidden=NO;
self.alpha=1;

[contentView release];
[scrollView release];

to make a scrollview zoomable do not forget to implement the UIScrollViewDelegate

and add:

-(UIView *) viewForZoomingInScrollView:(UIScrollView *)inScroll {
return contentView;}