使用水平滚动在图像视图上加载图像 [英] Load images on a image view using horizontal scrolling
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问题描述
我正在通过字符串在 UIImageView 上加载图像，我想要水平滚动来查看 UIImageView 。
在我的xib文件中，我有一个滚动视图，其中有一个图像视图。我正在使用此代码，但我的页面没有滚动，只有字符串中的第一个图像被加载。任何人都可以帮忙。
I'm loading images on the UIImageView through a string and i want horizontal scrolling to view the images on a UIImageView.
In my xib file I have a scroll view over which there is a image view. I'm using this code but my page is not scrolling and only the first image in the string is loaded.Can anyone please help.
代码：
-(void)viewDidLoad
{
count=1;
// imagesName = [[NSMutableArray alloc]initWithObjects :@"election_band_base.jpg", @"ElectionBoxAPPA-Hindi(1).jpg", @"photos.png", @"business.png", @"health.png", nil];
imagesName1 = [NSString stringWithFormat :@"election_band_base.jpg", @"ElectionBoxAPPA-Hindi(1).jpg", @"photos.png", @"business.png", @"health.png", nil];
[imagesName addObject:imagesName1];
items = [[NSMutableArray alloc]init];
// [_imageView1.image setImage=imagesName1];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
// _imageView1.image=[UIImage animatedImageWithImages:imagesName duration:0];
_imageView1.image=[UIImage imageNamed:imagesName1 ];
[self loadScrollView];
}
-(void)loadScrollView
{
scrollView.contentSize = CGSizeMake(0, scrollView.frame.size.height);
NSMutableArray *controllers = [[NSMutableArray alloc] init];
for (unsigned i = 0; i < [imagesName count]; i++) {
[controllers addObject:[NSNull null]];
}
self.viewControllers = controllers;
count=1;
// a page is the width of the scroll view
scrollView.pagingEnabled = YES;
scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * [imagesName count], scrollView.frame.size.height);
//scrollView.contentSize = CGSizeMake(900,80);
scrollView.showsHorizontalScrollIndicator =YES;
scrollView.showsVerticalScrollIndicator = YES;
scrollView.scrollsToTop = NO;
scrollView.delegate = self;
pageControl.numberOfPages = [imagesName count];
pageControl.currentPage = 0;
// pages are created on demand
// load the visible page
// load the page on either side to avoid flashes when the user starts scrolling
[self loadScrollViewWithPage:0];
[self loadScrollViewWithPage:1];
}
- (void)loadScrollViewWithPage:(int)page {
if (page < 0) return;
if (page >= [imagesName count])
return;
// replace the placeholder if necessary
controller = [viewControllers objectAtIndex:page];
if ((NSNull *)controller == [NSNull null]) {
NSString *deviceType = [UIDevice currentDevice].model;
if([deviceType isEqualToString:@"iPhone"])
{
controller = [[MyViewController alloc] initWithNibName:@"MyViewController" bundle:nil];
}
else{
controller = [[MyViewController alloc] initWithNibName:@"MyViewController_ipad" bundle:nil];
}
[controller initWithPageNumber:page];
[controller setArrData:imagesName];
[viewControllers replaceObjectAtIndex:page withObject:controller];
}
// add the controller's view to the scroll view
if (nil == controller.view.superview) {
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
controller.view.frame = frame;
[scrollView addSubview:controller.view];
}
}
- (void)unloadScrollViewWithPage:(int)page {
if (page < 0) return;
if (page >= [imagesName count]) return;
controller = [viewControllers objectAtIndex:page];
if ((NSNull *)controller != [NSNull null]) {
if (nil != controller.view.superview)
[controller.view removeFromSuperview];
[viewControllers replaceObjectAtIndex:page withObject:[NSNull null]];
}
}
- (void)scrollViewDidScroll:(UIScrollView *)sender {
// We don't want a "feedback loop" between the UIPageControl and the scroll delegate in
// which a scroll event generated from the user hitting the page control triggers updates from
// the delegate method. We use a boolean to disable the delegate logic when the page control is used.
if (pageControlUsed) {
// do nothing - the scroll was initiated from the page control, not the user dragging
return;
}
// Switch the indicator when more than 50% of the previous/next page is visible
CGFloat pageWidth = scrollView.frame.size.width;
int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
pageControl.currentPage = page;
// NSLog(@"current page %d",page);
// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
[self unloadScrollViewWithPage:page - 2];
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];
[self unloadScrollViewWithPage:page + 2];
count=page+1;
// A possible optimization would be to unload the views+controllers which are no longer visible
}
// At the begin of scroll dragging, reset the boolean used when scrolls originate from the UIPageControl
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollViewLoc
{
CGFloat pageWidth = scrollViewLoc.frame.size.width;
CGPoint translation = [scrollViewLoc.panGestureRecognizer translationInView:scrollViewLoc.superview];
int page = floor((scrollViewLoc.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
}
// At the end of scroll animation, reset the boolean used when scrolls originate from the UIPageControl
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
pageControlUsed = NO;
}
- (IBAction)changePage:(id)sender
{
int page = pageControl.currentPage;
// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];
// update the scroll view to the appropriate page
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
[scrollView scrollRectToVisible:frame animated:YES];
// Set the boolean used when scrolls originate from the UIPageControl. See scrollViewDidScroll: above.
pageControlUsed = YES;
}
推荐答案
所以，你想要构建图库视图：
So, you want to built the gallery view:
对于这个工具，需要执行以下步骤：
For this implement the following steps:
-
将
UIScrollView添加到视图控制器的视图中。
Add the
UIScrollViewto the view of your view controller.
在 viewDidLoad 方法：在ImageArray中加载图像的名称。 （我假设你的所有图像的名称都是img1.png，img2.png，img3.png，....）
In viewDidLoad method: Load the name of the images in the "ImageArray". (I assume all your images have names as "img1.png", "img2.png", "img3.png", ....)
ImageArray=[[NSMutableArray alloc]init];
for (int i=0; i<19; i++) {
NSString *imgtext=[[NSString alloc]initWithFormat:@"img%d",i+1];
[ImageArray addObject:imgtext];
}
在 viewWillAppear 方法，添加以下代码：
In the viewWillAppear method, add the following code:
for (int i = 0; i < ImageArray.count; i++) {
CGRect frame;
frame.origin.x = self.scrollview.frame.size.width * i;
frame.origin.y = 0;
frame.size = self.scrollview.frame.size;
UIView *subview = [[UIView alloc] initWithFrame:frame];
UIImage *image = [UIImage imageNamed: [NSString stringWithFormat:@"%@.png",[ImageArray objectAtIndex:i]]];
UIImageView *imageView = [[UIImageView alloc] initWithImage: image];
[imageView setFrame:CGRectMake(0, 0, frame.size.width,frame.size.height )];
[subview addSubview:imageView];
[self.scrollview addSubview:subview];
}
self.scrollview.contentSize = CGSizeMake(self.scrollview.frame.size.width * ImageArray.count, self.scrollview.frame.size.height);
self.scrollview.contentOffset=CGPointMake (self.scrollview.frame.size.width, 0);
希望有所帮助。
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