In my iPhone app i am getting around 300 images url from web server, i need to display all the images on UIScrollView in 3x3 row and column format. Once i get all the url from web server, convert them into UIImage and display image. Everything works fine, however after loading 200 images app crashes, I have read a lot its some thing memory kind of issue with UIScrollView, so how can we work on this. I have read apple documentation also, however its not clear.
here is the solution, i've implemented it in my app. Here is my code
sv_port is my scrollView.
Download SDWebImageDownloader class files and import it in your project. Add relevant framework in your project. like imageIO.framework, QuartzCore
Now, in your .m add
#import "UIImageView+WebCache.h"
#import "SDImageCache.h"
#import "SDWebImageCompat.h"
//function for adding image in your scrollview
-(void)populateImages
{
int x=6,y=6;
for(UIView * view in sv_port.subviews){
if([view isKindOfClass:[UIImageView class]])
{
[view removeFromSuperview]; view = nil;
}
if([view isKindOfClass:[UIButton class]])
{
[view removeFromSuperview]; view = nil;
}
}
for(int p=0;p<[Manufacturer count];p++)
{
UIButton *btnImageButton = [UIButton buttonWithType:UIButtonTypeCustom];
btnImageButton.frame = CGRectMake(x,y,70,70);
[btnImageButton setTag:p];
[btnImageButton addTarget:self action:#selector(nextview:) forControlEvents:UIControlEventTouchUpInside];
UIActivityIndicatorView *spinny = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
spinny.frame=CGRectMake(btnImageButton.frame.origin.x+25,btnImageButton.frame.origin.y+25, 20, 20);
spinny.backgroundColor=[UIColor clearColor];
[spinny startAnimating];
[sv_port setScrollEnabled:YES];
[sv_port addSubview:spinny];
UIImageView *asyncImageView = [[[UIImageView alloc] initWithFrame:btnImageButton.frame] autorelease];
asyncImageView.backgroundColor=[UIColor clearColor];
CALayer *layer;
layer = asyncImageView.layer;
layer.borderWidth = 0.5;
layer.cornerRadius = 5;
layer.masksToBounds = YES;
[asyncImageView setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:#"%#", yourUrl] ] placeholderImage:[UIImage imageNamed:nil] options:0 andResize:CGSizeMake(btnImageButton.frame.size.width,btnImageButton.frame.size.height) withContentMode:UIViewContentModeScaleAspectFit];
asyncImageView.contentMode = UIViewContentModeScaleAspectFit;
[sv_port addSubview:btnImageButton];
[sv_port addSubview:asyncImageView];
int imgCntPort=0;
imgCntPort=(sv_port.frame.size.width/(asyncImageView.frame.size.width));
////NSLog(#"imgport %d",imgCntPort);
if((p+1)%imgCntPort==0)
{
x=5;
y=y+80;
}
else
{
x=x+80;
}
}
sv_port.contentSize = CGSizeMake(0, y);
glob_x =0; glob_y =y;
}
hope it helps..
-(void)scrollimage
{
[AsyncImageLoader sharedLoader].cache = nil;
NSArray *viewsToRemove = [_scrollview_gallary subviews];
for (UIView *v in viewsToRemove) {
[v removeFromSuperview];
}
CGFloat width =_scrollview_gallary.bounds.size.width;
_scrollview_gallary.contentSize=CGSizeMake(width*[tmpArr count]-1, 360);
[_scrollview_gallary setShowsHorizontalScrollIndicator:NO];
[_scrollview_gallary setShowsVerticalScrollIndicator:NO];
int x=0;
int y=0;
for (int i=0; i<[tmpArr count]; i++)
{
AsyncImageView *imgv;
imgv =[[AsyncImageView alloc] initWithFrame:CGRectMake(x,y,width,360)];
imgv.contentMode = UIViewContentModeScaleToFill;
imgv.activityIndicatorStyle = UIActivityIndicatorViewStyleWhite;
NSString *strimag=[NSString stringWithFormat:#"%#",[tmpArr objectAtIndex:i]];
imgv.imageURL=[NSURL URLWithString:[tmpArr objectAtIndex:i]];
[_scrollview_gallary addSubview:imgv];
x=x+width;
}
_pageview.numberOfPages=([tmpArr count]);
_scrollview_gallary.pagingEnabled = YES;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
int page;
CGFloat pageWidth = _scrollview_gallary.frame.size.width;
page = floor((_scrollview_gallary.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
self.pageview.currentPage = page;
}
I am getting an impression that you are downloading all 300 images together at once and keeping in memory and adding to the UIScrollView..
There is a technique called LazyLoad, means don't load all the images at once, load it in queue..
You can refer to this link http://lazyloadinginuiscrollviewiniphone.blogspot.in/2011/12/iphone-uiscrollview-lazy-image-loading.html it might help you to achieve things smoothly..
All the best.
If you want to display images in Gridview format then you can use PSTCollectionView. And for the lazy loading of the image you can use SDWebImage.
Are you releasing the elements that are not visible anymore? UITableView does that (that's why Sandro suggested it).
Your implementation of the UIScrollView should do that.
You can also consider UICollectionView or GMGridView for grid implementations that take this into consideration.
I do not see why what you're doing is a problem. May be you've got memory issue. In that case simulator and device result should be different.
If this is a memory problem, you should use a tableview instead of a scroll view. Put 3 images in each table view cell, and that should do the trick.
Cdt
Related
Good day! Is there any way on how to reduce or revert the memory used to a freshly opened app state? I'm developing a Menu app for a restaurant. On the main screen i have a buttons for Main Course,Appetizers,Soups etc. If you click on one category it will take you to another view, That is UINavigation Controller with UITableViewController, now when you click on any row of that UITableView it will take you to another ViewController which contains UIScrollView with images. This Last ViewController has this code to loop many images.
self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0,
self.view.frame.size.width,
self.view.frame.size.height)];
self.scrollView.pagingEnabled = YES;
[self.scrollView setAlwaysBounceHorizontal:NO];
self.scrollView.showsHorizontalScrollIndicator = NO;
self.scrollView.scrollEnabled = YES;
//setup internal views
NSInteger numberOfViews = 5;
for (int i = 0; i < numberOfViews; i++) {
CGFloat xOrigin = i * self.view.frame.size.width;
image = [[UIImageView alloc] initWithFrame:
CGRectMake(xOrigin, 0,
self.view.frame.size.width,
self.view.frame.size.height)];
image.image = [UIImage imageNamed:[NSString stringWithFormat:
#"main_%d", i+1]];
image.contentMode = UIViewContentModeScaleAspectFit;
[self.scrollView addSubview:image];
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(updatePrices:) userInfo:nil repeats:YES];
}
//set the scroll view content size
self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width *
numberOfViews,
self.view.frame.size.height);
//add the scrollview to this view
[self.view addSubview:self.scrollView];
So basically in 1 Category Lets say Main Course, i have this
http://oi60.tinypic.com/f1fr0j.jpg
Each category i have that setup of views. Now, The main problem is, when i open the app, it only consumes 6MB, then when i Tap a button, to show the Menu for the selected category, it goes up to 17mb, Now When i click anything on the Food lists, and shows the image viewcontroller, it goes up to 68mb. I tried to add a button on each to and add some actions like this
- (IBAction)backToHome:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil];
self.view = nil;
}
The main problem is, When i go back to the MainViewController, The consumed Memory is there, so the app gets really slow if they select more categories because it increases the memory usage. How can i Reduce or "Clear Cache" of the used memory to prevent slowing the app? Thank you!
Calling imageNamed will always cache the image in the memory to increase speed, so event if you release holder view(s) the memory usage won't drop. Use some other method to load your images(imageWithContentsOfFile or other) and make caching by yourself if you need it at all.
#property(nonatomic, strong) NSMutableDictionary* cachedImages;
-(UIImage*)imageNamedBOOM:(NSString*)aImageName
{
UIImage* result = _cachedImages[aImageName];
if( !result )
{
result = [UIImage imageWithContentsOfFile:aImageName];
_cachedImages[aImageName] = result;
}
return result;
}
-(void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
[_cachedImages removeAllObjects];
}
And then in your code just call it like this(note that you have to provide image extension png, jpg, etc):
-(void) setupScrollView {
//add the scrollview to the view
self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0,
self.view.frame.size.width,
self.view.frame.size.height)];
self.scrollView.pagingEnabled = YES;
[self.scrollView setAlwaysBounceVertical:NO];
//setup internal views
NSInteger numberOfViews = 3;
for (int i = 0; i < numberOfViews; i++) {
CGFloat xOrigin = i * self.view.frame.size.width;
UIImageView *image = [[UIImageView alloc] initWithFrame:
CGRectMake(xOrigin, 0,
self.view.frame.size.width,
self.view.frame.size.height)];
image.image = [self imageNamedBOOM:[NSString stringWithFormat:
#"image_%d.png", i+1]];//make sure here you provide proper image extension JPG, PNG or other
image.contentMode = UIViewContentModeScaleAspectFit;
[self.scrollView addSubview:image];
}
//set the scroll view content size
self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width *
numberOfViews,
self.view.frame.size.height);
//add the scrollview to this view
[self.view addSubview:self.scrollView];
}
And in back to home:
- (IBAction)backToHome:(id)sender {
[_cachedImages removeAllObjects]
[self dismissViewControllerAnimated:YES completion:nil];
self.view = nil;
}
Im trying to refactor my code for better memory management and performance. I have an array of 12 images, but I want to load them as needed, not all at the same time. So maybe the current image -1, the current image and the current image +1. I viewed some of the answers on SO but found them unclear. I felt it would be clearer if I posted my code for reference.
//scroll view set up
- (void)scrollViewSetUp
{
self.scrollview.delegate = self;
for (int i = 0; i < _images.count; i++)
{
CGRect frame;
frame.origin.x = self.scrollview.frame.size.width * i;
frame.size = self.scrollview.frame.size;
self.scrollview.pagingEnabled = YES;
UIImageView *subview = [[UIImageView alloc] initWithFrame:frame];
subview.image = [UIImage imageNamed:[_images objectAtIndex:i]];
[self.scrollview addSubview:subview];
}
self.scrollview.contentSize = CGSizeMake(self.scrollview.frame.size.width * _images.count, self.scrollview.frame.size.height);
self.automaticallyAdjustsScrollViewInsets = NO;
//page control ie .... at bottom of
self.pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(100.0,0.0,100.0,40.0)];
[self.pageControl setNumberOfPages:_images.count];
[self.pageControl setCurrentPage:0];
self.pageControl.pageIndicatorTintColor = [UIColor lightGrayColor];
self.pageControl.currentPageIndicatorTintColor = [UIColor whiteColor];
[self.pageControl setBackgroundColor:[UIColor clearColor]];
[self.viewForPageControl addSubview:self.pageControl];
[self.viewForPageControl setBackgroundColor:[UIColor clearColor]];
}
#pragma mark - UIScrollView Delegate
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
int newOffset = scrollView.contentOffset.x;
int newPage = (int)(newOffset/(scrollView.frame.size.width));
[_pageControl setCurrentPage:newPage];
}
Any advice or direction is greatly appreciated.
As per Gman's request I reposted my comment.
This tutorial will help you:
http://www.raywenderlich.com/10518/how-to-use-uiscrollview-to-scroll-and-zoom-content
You could try to reuse your UIImageView as they go offscreen... but you'll be just trying to redo what UITableview already does. UITableView with a custom UITableViewCell would take care of notifying you when new cells comes visible and dequeuing the ones that are offscreen.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *cellIdentifier = #"yourCustomImageCell";
//look if there are cells that could be reused
CustomImageCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell) { //if not, create a new one
cell = [[CustomImageCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
}
//Set your image here
return cell;
}
Not sure if this is the best way of doing it, but it's an option.
You can set the tag property on your UIImageView to correspond to your index in your loop when setting the scrollView.
Then in your scrollViewDidEndDecelerating method:
for (int i = 0; i < _salonImages.count; i++)
{
if(i == (newPage-1))
{
UIImageView *imgView = (UIImageView*)[self.scrollView viewWithTag:newPage-1];
imgView.image = [_images objectAtIndex:newPage-1];
}
else if(i == newPage)
{
UIImageView *imgView = (UIImageView*)[self.scrollView viewWithTag:newPage];
imgView.image = [_images objectAtIndex:newPage];
}
else if(i == (newPage + 1 ))
{
UIImageView *imgView = (UIImageView*)[self.scrollView viewWithTag:newPage+1];
imgView.image = [_images objectAtIndex:newPage+1];
}
else
{
UIImageView *imgView = (UIImageView*)[self.scrollView viewWithTag:i];
imgView.image = nil;
}
}
I'm using iCarousel library in my small app. I'm getting the image urls via web service and placing those images to the iCarousel library.
First I created a UIView and added iCarousel as respective class to it. Latter set the datasourse and delete gate to same class.
Now everything looks cool and I could see the images but I couldn't swipe the images.
Following is my code.
- (NSUInteger)numberOfItemsInCarousel:(iCarousel *)carousel
{
//return the total number of items in the carousel
return [galleryItems count];
}
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{
UILabel *label = nil;
//create new view if no view is available for recycling
if (view == nil)
{
//NSString *ImageURL = #"YourURLHere";
//NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:ImageURL]];
//imageView.image = [UIImage imageWithData:imageData];
view = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 200.0f, 200.0f)];
//[((UIImageView *)view) setImageWithURL:[NSURL URLWithString:#"http://www.pizzatower.com/img/icons/Pizza-icon.png"]];
NSURL *imageURL = [[galleryItems objectAtIndex:index] galleryURL];
[((UIImageView *)view) setImageWithURL:imageURL];
view.contentMode = UIViewContentModeScaleAspectFit;
label = [[UILabel alloc] init];
label.backgroundColor = [UIColor clearColor];
label.font = [label.font fontWithSize:20];
label.tag = 1;
// label.contentMode = UIViewContentModeBottom;
// label.frame = CGRectMake(
// self.view.frame.size.width - label.frame.size.width,
// self.view.frame.size.height - label.frame.size.height,
// label.frame.size.width,
// label.frame.size.height );
//label.bounds = view.bounds;
[view addSubview:label];
}
else
{
//get a reference to the label in the recycled view
label = (UILabel *)[view viewWithTag:1];
}
//set item label
//remember to always set any properties of your carousel item
//views outside of the `if (view == nil) {...}` check otherwise
//you'll get weird issues with carousel item content appearing
//in the wrong place in the carousel
//label.text = [[galleryItems objectAtIndex:index] galleryDescription];
return view;
}
I've used same code base and it worked in some other project. No idea what am I missing here. Can someone please enlighten me.
You UIView containing the carousel may have userInteractionEnabled set to NO.
Another possibility is that the UIView containing the carousel may be smaller than the carousel and so be blocking interaction. Try setting its background color to see its true size.
I'd suggest delete your nib or the ViewController in your storyboard and re-create it. I had the same issue once and after re-creating it it worked. Make sure you center your UIView when placing it (both horizontally and vertically)
I'm currently developping an iPad app and I need a "Slideshow"
So I create a first UIScrollView which will be used as pager and in the viewDidLoad I use a "for" loop to put the content in the UIScrollView.
Here is the loop :
for (int i = 0; i < self.thumbs.count; i++) {
UIScrollView *subScroll = [[UIScrollView alloc]initWithFrame:CGRectMake(self.ThumbsSlider.frame.size.width * i, 0, self.ThumbsSlider.frame.size.width, self.ThumbsSlider.frame.size.height)];
[subScroll setDelegate:self];
[subScroll setScrollEnabled:YES];
[subScroll setBouncesZoom:YES];
[subScroll setClipsToBounds:YES];
[subScroll setContentMode:UIViewContentModeCenter];
subviewImage = [[AsyncImageView alloc] initWithFrame:CGRectMake(0 , 0, subScroll.frame.size.width, subScroll.frame.size.height)];
subviewImage.contentMode = UIViewContentModeScaleAspectFit;
subviewImage.userInteractionEnabled = YES;
subviewImage.image = [UIImage imageNamed:#"no-image.jpg"];
subviewImage.imageURL = [NSURL URLWithString:[self.thumbs objectAtIndex:i]];
[subScroll addSubview:subviewImage];
subScroll.minimumZoomScale = 1.0;
subScroll.maximumZoomScale = 3.0;
[[subScroll delegate]viewForZoomingInScrollView:subScroll];
[self.ThumbsSlider addSubview:subScroll];
}
When I launch the app on my iPad, there is no crashes.
But, when I try to zoom, the contentSize of my subScroll change but the subviewImage doesn't zoom !
Can someone explain me why ?
Thanks in advance !
Put this function in your controller
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
for (UIView *imageView in scrollView.subviews)
{
if ([imageView isKindOfClass:[AsyncImageView Class]])
{
return imageView;
}
}
return nil;
}
And remove below line from loop:
[[subScroll delegate]viewForZoomingInScrollView:subScroll];
i have a modal view that is called from a table view. Whenever i call the modal view, i set a small view, inside the modal view, with some scrollable pictures inside it. The problem is that when i go back to the table view and select another row of the table, the old images are supposed to disappear and the new ones appear instead, but that is not happening. Seems like when i first load the modal view, it fills with the initial 2 pics and when i load it again it keeps adding the new pictures with the old ones..
Here is the code:
- (void)layoutScrollImages {
UIImageView *view = nil;
NSArray *subviews = [scrollView1 subviews];
//NSMutableArray *subviews = [scrollView1 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
[scrollView1 setContentSize:CGSizeMake(([self.nomeFotos count] * kScrollObjWidth), [scrollView1 bounds].size.height)];
}
and:
- (void)setScrollingImages {
//self.view.backgroundColor = [UIColor viewFlipsideBackgroundCol];
// 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
[scrollView1 setBackgroundColor:[UIColor blackColor]];
[scrollView1 setCanCancelContentTouches:NO];
scrollView1.indicatorStyle = UIScrollViewIndicatorStyleWhite;
scrollView1.clipsToBounds = YES; // default is NO, we want to restrict drawing within our scrollview
scrollView1.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.
scrollView1.pagingEnabled = YES;
// load all the images from our bundle and add them to the scroll view
NSUInteger i;
for (i = 1; i <= [self.nomeFotos count]; i++)
{
NSString *imageName = [NSString stringWithFormat:[self.nomeFotos objectAtIndex:(i-1)]];
UIImage *image = [UIImage imageNamed:imageName];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
NSLog(#"%#", imageName);
// 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
[scrollView1 addSubview:imageView];
}
[self layoutScrollImages]; // now place the photos in serial layout within the scrollview
}
i just figured what i wanted, a solution is to remove all the current subviews and then add the new views.. the code is as follow:
for (UIView* subView in [self.view.subviews]) {
[subView removeFromSuperview];
}
I put this code in my view will appear and everytime the view appears, it clears its subviews and the i call the method to add the new subviews (pictures).
Thanks