我在滚动视图中有一个问题。
现在我写了一个关于带有滚动视图的图片库的示例。我在滚动视图中添加了很多图像。每次显示3个图像,问题是如何正确测量滚动。例如:每次滚动最少移动 1 张图像。现在,我认为每次滚动时,移动的最小图像是 3。这让我无法在我想看到的正确图像上停下来。下面是代码。
- (void)layoutScrollImages
{
UIImageView *view = nil;
NSArray *subviews = [scroll subviews];
// reposition all image subviews in a horizontal serial fashion
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);
}
}
// set the content size so it can be scrollable
[scroll setContentSize:CGSizeMake((kNumImages * kScrollObjWidth), [scroll bounds].size.height)];
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
// 1. setup the scrollview for multiple images and add it to the view controller
//
// note: the following can be done in Interface Builder, but we show this in code for clarity
[scroll setBackgroundColor:[UIColor blackColor]];
[scroll setCanCancelContentTouches:NO];
scroll.indicatorStyle = UIScrollViewIndicatorStyleWhite;
scroll.clipsToBounds = YES; // default is NO, we want to restrict drawing within our scrollview
scroll.scrollEnabled = YES;
// pagingEnabled property default is NO, if set the scroller will stop or snap at each photo
// if you want free-flowing scroll, don't set this property.
scroll.pagingEnabled = YES;
// load all the images from our bundle and add them to the scroll view
NSUInteger i;
for (i = 1; i <= kNumImages; i++)
{
NSString *imageName = [NSString stringWithFormat:@"image%d.jpg", i];
UIImage *image = [UIImage imageNamed:imageName];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
// setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
CGRect rect = imageView.frame;
rect.size.height = kScrollObjHeight;
rect.size.width = kScrollObjWidth;
imageView.frame = rect;
imageView.tag = i; // tag our images for later use when we place them in serial fashion
[scroll addSubview:imageView];
[imageView release];
}
[self layoutScrollImages];
}