I have implemented iCarousel for my Banner View on iPad with this relevant codes:
- (NSInteger)numberOfItemsInCarousel:(__unused iCarousel *)carousel
{
return (NSInteger)[self.bannerDatas count];
}
- (UIView *)carousel:(__unused iCarousel *)carousel viewForItemAtIndex:(NSInteger)index reusingView:(UIView *)view
{
if (view == nil)
{
view = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 215.0f, 155.0f)];
((UIImageView *)view).image = [UIImage imageNamed:[self.netImages objectAtIndex:index]];
view.contentMode = UIViewContentModeCenter;
}
return view;
}
But the problem lies here at this line:
((UIImageView *)view).image = [UIImage imageNamed:[self.netImages objectAtIndex:index]];
netImages need to be image's name in order to get this works but my netImages contain array of images' URLs. So my question is how to use image URL instead of name for Carousel?
Here below is how netImages get data:
- (NSArray *)setUpNetImages {
self.netImages = [NSMutableArray new];
for (BannerData *data in self.bannerDatas) {
if (data.imageUrl != nil) {
[self.netImages addObject:data.imageUrl]; //original
}
}
return self.netImages;
}
Please Use SDwebImage that provide you functionality to download your image in Asynchronous orderer from url and update your image once downloading done.and your UI never get halt.
((UIImageView *)view)sd_setImageWithURL:[NSURL URLWithString:[self.netImages objectAtIndex:index]]
placeholderImage:[UIImage imageNamed:#"placeholder.png"]]
You just need to add it and import
#import <SDWebImage/UIImageView+WebCache.h>
Related
I'm using iCarousel to display images clicked by the user and are reloaded dynamically into the carousel. The whole setup works perfectly with default values for iCarouselOptionVisibleItems but images start to scale up when the total number of images exceeds 8.
TO try and fix the issue i increased the number of iCarouselOptionVisibleItems to 25 and that temporarily fixed the issue but i know thats not the best solution because the images will still scale after the number exceeds 25. Is there something I'm missing from the documentation that I'm missing?
Here's the code for my icarousel screen
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
self.carousel.delegate = self;
self.carousel.dataSource = self;
_carousel.type = iCarouselTypeCoverFlow2;
}
- (NSUInteger)numberOfItemsInCarousel:(iCarousel *)carousel
{
//return the total number of items in the carousel
return [images count];
}
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
//create new view if no view is available for recycling
if (view == nil)
{
//don't do anything specific to the index within
//this `if (view == nil) {...}` statement because the view will be
//recycled and used with other index values later
view = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 200.0f, 200.0f)];
view.contentMode = UIViewContentModeScaleAspectFit;
((UIImageView *)view).image = [UIImage imageWithContentsOfFile:[images objectAtIndex:index]];
}
else
{
//get a reference to the label in the recycled view
view.contentMode = UIViewContentModeScaleAspectFit;
view = [[UIImageView alloc] initWithImage:[UIImage imageWithContentsOfFile:[images objectAtIndex:index]]];
}
return view;
}
- (CGFloat)carousel:(iCarousel *)carousel valueForOption:(iCarouselOption)option withDefault:(CGFloat)value
{
if (option == iCarouselOptionSpacing)
{
return value * 1.1f;
}
else if (option == iCarouselOptionVisibleItems)
{
return 25;
}
return value;
}
I am using iCarousel custom control to show image from web that consumed with JSON data.
Here is my codes to show image in iCarousel
to Load JSON Data in ViewDidLoad
JSONLoader *jsonLoader = [[JSONLoader alloc]init];
self.items = [[NSMutableArray alloc]init];
[self.items removeAllObjects];
self.items = (NSMutableArray *) [jsonLoader loadJSONDataFromURL:[NSURL URLWithString:#"https://public-api.wordpress.com/rest/v1/sites/www.myWebsite.com/posts?category=blog&page=1"]];
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(AsyncImageView *)view
{
MMSPLoader *mmObject = [self.items objectAtIndex:index];
view = [[AsyncImageView alloc]initWithFrame:CGRectMake(0, 0, 250.0f, 250.0f)];
view.layer.borderColor = [UIColor whiteColor].CGColor;
view.layer.borderWidth = 0.3f;
view.image=[UIImage imageNamed:#"page.png"];
view.imageURL = [NSURL URLWithString:[mmObject featureImageUrl]];
return view;
}
That can show image correctly. My case is when i tap on that image , i want to show that image in FULL SCREEN. So i used GGFullScreenImageViewController.
However when i tap on that Image to show FULL SCREEN , i retrieved Image URL and show in GGFullScreenImageViewController. It's fine but , i don't want to retrieve from that URL because it downloading image from web again and slowing to show.
In my idea , i saved that image when tap on image in iCarousel and show it in GGFullScreenImageViewController.
So i don't need to download image again.
- (void)carousel:(iCarousel *)carousel didSelectItemAtIndex:(NSInteger)index
{
dispatch_queue_t myqueue = dispatch_queue_create("com.i.longrunningfunctionMain", NULL);
dispatch_async(myqueue, ^{
UIApplication *apps = [UIApplication sharedApplication];
apps.networkActivityIndicatorVisible = YES;
MMLoader *mmObject = [self.items objectAtIndex:index];
NSData *data = [[NSData alloc]initWithContentsOfURL:[NSURL URLWithString:mmObject.featureImageUrl]];
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageWithData:data]];
GGFullscreenImageViewController *vc = [[GGFullscreenImageViewController alloc] init];
vc.liftedImageView = imageView;
dispatch_async(dispatch_get_main_queue(), ^{
apps.networkActivityIndicatorVisible = NO;
[self presentViewController:vc animated:YES completion:nil];
});
});
NSLog(#"%i",index);
}
So should i save to local file or is there any others nice idea?
Really you should use a library to save the image when you initially download it. AsyncImageView isn't necessarily the best choice as it just caches in memory.
That said, at the moment you can just get the image from the view. This isn't ideal, and you should save it to disk - just sooner rather than later. Look at, perhaps, SDWebImage for that.
To get the image from the view (typed in browser so verify syntax and API usage...):
- (void)carousel:(iCarousel *)carousel didSelectItemAtIndex:(NSInteger)index
{
AsyncImageView *view = (AsyncImageView *)[carousel itemViewAtIndex:index];
UIImageView *imageView = [[UIImageView alloc] initWithImage:view.image];
GGFullscreenImageViewController *vc = [[GGFullscreenImageViewController alloc] init];
vc.liftedImageView = imageView;
[self presentViewController:vc animated:YES completion:nil];
}
I'm using Nick Lockwood's iCarousel for an iPad app. Right now it's just a carousel of 15 full screen images.
I setup a single view project, add the iCarousel view in storyboard, add it's view controller as a data source and put this code for the datasource methods:
- (NSUInteger)numberOfItemsInCarousel:(iCarousel *)carousel {
return 15;
}
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view {
UIImage* img = [UIImage imageNamed:[NSString stringWithFormat:#"image%d.jpg", index]];
UIImageView* imgView = [[UIImageView alloc] initWithImage:img];
return imgView;
}
This works, but the first time I scroll through all the items you can notice a little performance hit when a new item is being added to the carousel. This does not happen the second time I go through all the items.
You can see what I mean in this profiler screenshot. The peaks in the first half are for the first time I scroll through all the images, then I do it again and there are no peaks and no performance hit.
How can I fix this?
EDIT
I isolated one of the peaks on instruments and this is the call tree
EDIT
The code with jcesar suggestion
- (void)viewDidLoad {
[super viewDidLoad];
NSMutableArray* urls_aux = [[NSMutableArray alloc] init];
for (int i = 0; i<15; i++) {
NSString *urlPath = [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:#"captura%d", i] ofType:#"jpg"];
NSURL *url = [NSURL fileURLWithPath:urlPath];
[urls_aux addObject:url];
}
self.urls = urls_aux.copy;
self.carousel.dataSource = self;
self.carousel.type = iCarouselTypeLinear;
}
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view {
if (view == nil) {
view = [[[AsyncImageView alloc] initWithFrame:CGRectMake(0, 0, 1024, 768)] autorelease];
view.contentMode = UIViewContentModeScaleAspectFit;
}
[[AsyncImageLoader sharedLoader] cancelLoadingImagesForTarget:view];
((AsyncImageView *)view).imageURL = [self.urls objectAtIndex:index];
return view;
}
I don't think this is a very orthodox solution, but it works.
What I do is use iCarousel's method insertItemAtIndex:animated: to add the images one at a time on setup. Performance gets hit then, but after that everything runs smoothly.
- (void)viewDidLoad
{
[super viewDidLoad];
self.images = [[NSMutableArray alloc] init];
self.carousel.dataSource = self;
self.carousel.type = iCarouselTypeLinear;
for (int i = 0; i<15; i++) {
UIImage* img = [UIImage imageNamed:[NSString stringWithFormat:#"captura%d.jpg", i]];
[self.images addObject:img];
[self.carousel insertItemAtIndex:i animated:NO];
}
}
- (NSUInteger)numberOfItemsInCarousel:(iCarousel *)carousel {
return self.images.count;
}
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view {
UIImage* img = [self.images objectAtIndex:index];
UIImageView* imgView = [[UIImageView alloc] initWithImage:img];
return imgView;
}
It's hard to be certain, but I'd guess that the first time through it's loading the images from the file; whereas the second time it's using the cached copies - that's something that +[UIImage imageNamed:] does automatically for you; without it, you'd see the performance hit every time. You could load the images earlier, either in your app delegate or in the initialiser for your controller.
Another thing you could do would be to make use of iCarousel's view reuse logic. I don't think it's responsible for your problem, but you may as well do it now:
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view {
UIImage* img = [UIImage imageNamed:[NSString stringWithFormat:#"image%d.jpg", index]];
UIImageView* imgView = nil;
if ([view isKindOfClass:[UIImageView class]])
{
imgView = (UIImageView *)view;
imgView.image = img;
[imgView sizeToFit];
}
else
{
[[UIImageView alloc] initWithImage:img];
}
return imgView;
}
UPDATE: It would be great to get a bit more information on where your app is spending its time. If you use the Instruments Time Profiler you can get a breakdown of what percentage of the time is spent in each method.
Look at his example: Dynamic Downloads. He uses AsyncImageView instead UIImageView, that loads the images in an async way. So it won't try to load all the 15 images at the same time, and I think it shouldn't have performance issues
I have a basic implementation for iCarousel where I am pulling images from a core-data store. I am experiencing memory related crashes when you get a lot of images loaded, as I guess is expected. The problem is I don't know of any way to use the AsyncImageView library since there is no NSURL reverence for a core-data object. Anyone know another way to manage this memory issue?
Here is my iCarousel viewForItemAtIndex
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
JournalEntry *journalEntry = (JournalEntry *)[fetchedResultsController objectAtIndexPath:[NSIndexPath indexPathForRow:index inSection:0]];
if (view == nil)
{
view = [[[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 240.0f, 240.0f)] autorelease];
view.contentMode = UIViewContentModeScaleAspectFit;
}
[((UIImageView *)view) setImage:[journalEntry.image valueForKey:#"image"]];
NSLog(#"%i", index);
return view;
}
For reference here is code for adding images to my core-data store straight out of the iPhoneCoreDataRecipes sample code.
#implementation ImageToDataTransformer
+ (BOOL)allowsReverseTransformation {
return YES;
}
+ (Class)transformedValueClass {
return [NSData class];
}
- (id)transformedValue:(id)value {
NSData *data = UIImagePNGRepresentation(value);
return data;
}
- (id)reverseTransformedValue:(id)value {
UIImage *uiImage = [[UIImage alloc] initWithData:value];
return [uiImage autorelease];
}
#end
After studying this for a while it turns out the large memory growth is due to the coredata cache and not iCarousel. This can be cleared by calling reset on the managedObjectContext.
My code is below
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
UIImageView *imgView = nil;
if (view == nil)
{
NSLog(#"no is %i",index);
view = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 255, 255)] autorelease];
imgView = [[[UIImageView alloc] initWithImage:[ImagesCFArray objectAtIndex:index]] autorelease];
[view addSubview:imgView];
}
else
{
}
return view;
}
ImagesCfArray contains the images to be displayed. 0th index image overlapping with other images when carousel moves or scrolls. Please give me solution for this.
Can you show your itemWidth implementation? Does it return more than 255?
You might want to tell the subview to clip to its bounds:
imgView.clipToBounds = YES;
And also, perhaps use a fill for the image:
imgView.contentMode = UIViewContentModeScaleAspectFit;