Images constrain's :
Image is set to scale-fill.
I am using SDWebImage Library to load images from server..
When image is loaded it over lap's the text area which is exactly below my image.
Here are the screen shot's of main layout.. No issues from constrain's found.
Here is the image when it load's look like:
Here is the code:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
cell=[tableView dequeueReusableCellWithIdentifier:#"fiscocustomcell"];
int i = (int) indexPath.row;
Newsletter * newstemp = [newsposts objectAtIndex:i];
//get a dispatch queue
;
cell.Title.text=[newstemp title];
cell.Title.numberOfLines=0;
[cell.Title sizeToFit];
cell.Postedby.text=#"Posted by";
cell.Postedby.numberOfLines =0;
[cell.Postedby sizeToFit];
cell.NewsDesc.text=[newstemp desc];
cell.NewsDesc.numberOfLines=0;
[cell.NewsDesc sizeToFit];
NSURL *urlimage = [NSURL URLWithString:[newstemp imagelink]];
[cell.imageView sd_setImageWithURL:urlimage placeholderImage:[UIImage imageNamed:#"service-1.png"]];
[cell setNeedsDisplay];
[cell layoutIfNeeded];
return cell;
}
I am stucked from last 1 week with this issues used auto resolve constrain's etc as well nothing works.
It should be like this:
Solved Problem
The issue is cell.imageView, I am using custom cell so it must be custom uiimage naned there like:
[cell.mycustomimage sd_setImageWithURL:urlimage placeholderImage:[UIImage imageNamed:#"service-1.png"]];
cell.imageView alway's place the image on the right of cell.
Thanks every one hope that bug will never happen's to any one again ever...
Related
My image data is being loaded from core data into a UITableView cell. These images are automatically scaled by the OS (as far as I know) in cellForRowAtIndexPath:indexPath:. Not surprisingly, this causes a lot of lag while scrolling through the table view.
Similarly, I have a UICollectionViewController that loads all the same images into a collection view similar to the iOS Photos app and again, the images are scaled in cellForItemAtIndexPath:indexPath. Scrolling is laggy, but it also takes a very long time for the VC to load.
What is the best way to optimize performance in this scenario?
I've done some research and have come up with a couple possible solutions:
Initialize a "thumbnailArray" in viewDidLoad:animated:, scaling all the images I need before the table/collection view is loaded, then use this new array as the data source for the views. I figure this will solve the scrolling issue, but not the collection view loading issue.
Create new properties for thumbnail data in my image wrapper class. This data would be created when the image wrapper object is created (i.e. when the user adds an image) and saved in core data. I think this would be preferred over option #1.
Is option two the best way to go, or is there a better solution I am unaware of?
Here are my cellForRowAtIndexPath:indexPath and cellForItemAtIndexPath:indexPath: methods:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
CMAEntryTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"entriesCell" forIndexPath:indexPath];
CMAEntry *entry = [self.entries objectAtIndex:indexPath.item];
cell.speciesLabel.text = [entry.fishSpecies name];
cell.dateLabel.text = [self.dateFormatter stringFromDate:entry.date];
if (entry.location)
cell.locationLabel.text = [entry locationAsString];
else
cell.locationLabel.text = #"No Location";
if ([entry.images count] > 0)
cell.thumbImage.image = [[entry.images objectAtIndex:0] dataAsUIImage];
else
cell.thumbImage.image = [UIImage imageNamed:#"no_image.png"];
if (indexPath.item % 2 == 0)
[cell setBackgroundColor:CELL_COLOR_DARK];
else
[cell setBackgroundColor:CELL_COLOR_LIGHT];
return cell;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"thumbnailCell" forIndexPath:indexPath];
UIImageView *imageView = (UIImageView *)[cell viewWithTag:100];
[imageView setImage:[[self.imagesArray objectAtIndex:indexPath.item] dataAsUIImage]];
return cell;
}
Thanks in advance!
Cohen
Thanks for your input, guys, but this is the solution that worked really well for me. The only thing I don't like is that now I store an NSData instance of the full image, and two different sized thumbnail images in core data; however, that doesn't seem to be a problem.
What I did was add a couple attributes to my NSManagedObject subclass to store the thumbnail images. The thumbnail data is initialized when the image is selected by the user, then saved in core data along with the original image.
Then, I load the thumbnails into a collection asynchronously in the view controllers I need them.
Works great. Gets rid of all issues I was experiencing.
1 I think the best approach is to load images in a background thread so the tableview loads quickly.
2 Also you can use coredata feature of batchsize to load only necessary data.
3 Perhaps using some type of cache in memory for the images may help
In one of my project i faced same kind of issue and i solved it by using AsyncImageView for loading the thumbimage for my tableview cell.It will load the image asynchronously.
#property (nonatomic,strong)AsyncImageView * thumbImageView;
self.thumbImageView =[[AsyncImageView alloc] init];
cell.thumbImageView.imageURL =[NSURL fileURLWithPath:UrlString];
I have the smooth scrolling issue at my UITableView with UITableViewCell which contains UIImageView. Similar issues could be found all over the StrackOverflow but none of the proposed solutions helped me to completely get rid of the lag.
My case is quite common:
images are stored at application storage (in my sample at app bundle)
images could have different size (500x500, 1000x1000, 1500x1500)
I need to display those images in UITableView where UIImageView size is 120x120 (retina)
I have followed multiple optimization tips and managed to optimize scrolling a lot.
Unfortunately it is still not perfect. This is my scenario:
first I moved all the image loading/processing/resizing logic to the background thread
UITableViewCell reuse is enabled
once UITableViewCell is in view I clear old values (settings to null) and start background thread to load the image
at this point we are in background thread and I'm adding 500 ms delay to avoid settings new image to often (in case we are scrolling fast) (see below explanation)
if UIImage exists at static image cache (regular dictionary with UIImage instances) - fetch that one and go to the step 9.
if not - load new image from bundle (imageWithName) using url to app bundle (in real world scenario images will be stored to application storage, not bundle)
once image is loaded resize it to 120x120 using graphics context
save resized image to the static image cache
at this point we have instance to UIImage and process is in the background thread. From here we move back to UI Thread with the given image
if data context was cleared (for example UITableViewCell disappeared or was reused to display another image) we skip processing of the currently available image.
if data context is the same - assign UIImage to UIImageView with an alpha animation (UIView.Animate)
once UITableViewCell is out of view - clear the data context
Originally before starting new background thread to fetch the image here (step 1) was UIImage cache check without background thread. In this case if we have the image in the cache we assign it instantly and this introduces a great lag during fast scrolling (we assign images to often as long as we fetch them instantly). Those lines are commented at my example attached below.
There are still two issues:
at some point during scrolling I still have a small lag (at the
moment when I'm assign new UIImage to UIImageView.
(this one is more noticeable) when you tap on item and go back from details there is a lag right before back navigation animation is finished.
Any suggest how to deal with those two issues or how to optimize my scenario are appreciated
Please take into account that sample written in Xamarin but I don't believe that Xamarin is the cause of the problem as long as I have the same issue for the app written in ObjectiveC as well.
Smooth Scrolling Test App
Did you every tried to populate your TableView with only one 120x120 Image which is saved in your Bundle? This way you can check, if the problem occurs of your Image rendering
Instead of resizing all your images to 120x120 and save them in cache, I would recommend creating and using a thumbnail of all your images. You are somehow already doing this, but you are doing this couple of times (everytime you are scrolling or if your cache is full).
In our last project we had a UICollectionView with book covers. Most of the covers were between 400-800kb big and the feeling while scrolling was really bad. So we created a thumbnail for each image (thumbails about 40-50kb) and used the thumbnails instead of real covers. Works like a charm! I attached the thumbnail creation function
- (BOOL) createThumbnailForImageAtFilePath:(NSString *)sourcePath withName:(NSString *)name {
UIImage* sourceImage = [UIImage imageWithContentsOfFile:sourcePath];
if (!sourceImage) {
//...
return NO;
}
CGSize thumbnailSize = CGSizeMake(128,198);
float imgAspectRatio = sourceImage.size.height / sourceImage.size.width;
float thumbnailAspectRatio = thumbnailSize.height/thumbnailSize.width;
CGSize scaledSize = thumbnailSize;
if(imgAspectRatio >= thumbnailAspectRatio){
//image is higher than thumbnail
scaledSize.width = scaledSize.height * thumbnailSize.width / thumbnailSize.height;
}
else{
//image is broader than thumbnail
scaledSize.height = scaledSize.width * imgAspectRatio;
}
UIGraphicsBeginImageContextWithOptions( scaledSize, NO, 0.0 );
CGRect scaledImageRect = CGRectMake( 0.0, 0.0, scaledSize.width, scaledSize.height );
[sourceImage drawInRect:scaledImageRect];
UIImage* destImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSString* thumbnailFilePath = [[self SOMEDIRECTORY] stringByAppendingPathComponent:name];
BOOL success = [UIImageJPEGRepresentation(destImage, 0.9) writeToFile:thumbnailFilePath atomically:NO];
return success;
}
Try facebook's Async Display library.
https://github.com/facebook/AsyncDisplayKit
Really easy to use.. from their guide: http://asyncdisplaykit.org/guide/
_imageNode = [[ASImageNode alloc] init];
_imageNode.backgroundColor = [UIColor lightGrayColor];
_imageNode.image = [UIImage imageNamed:#"hello"];
_imageNode.frame = CGRectMake(10.0f, 10.0f, 40.0f, 40.0f);
[self.view addSubview:_imageNode.view];
This decodes the image on a background thread.
I'm not sure if it's easy to use iOS libraries on Xamarin but if it's easy, give this a shot.
I sub-class Paul Hegarty's CoreDataTableViewController and employ thumbnails of my photos in the CoreDataTableView.
Look for the examples in Lecture 14 titled FlickrFetcher and Photomania. You will also need to download the CoreDataTableViewController at that same link.
Make a CoreData Entity with an appropriate title and define whatever attributes (data variables) you want. You will need to define two "Transformable" attributes, one for the photo and one for the thumbnail.
Then load your thumbnail in the CoreDataTableView:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSArray *exceptions = [NSArray arrayWithObjects:#"SCR", #"DNS", #"NT", #"ND", #"NH", nil];
static NSString *CellIdentifier = #"resultsDisplayCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
MarksFromMeets *athleteMarks = [self.fetchedResultsController objectAtIndexPath:indexPath];
NSString* date = [ITrackHelperMethods dateToAbbreviatedString:athleteMarks.meetDate];
NSMutableString *title = [NSMutableString stringWithFormat:#"%#", athleteMarks.markInEvent];
NSMutableString *subTitle = [NSMutableString stringWithFormat:#"%# - %#",date, athleteMarks.meetName];
[title replaceOccurrencesOfString:#"(null)"
withString:#""
options:0
range:NSMakeRange(0, [title length])];
// cell.imageView.image = athleteMarks.photoThumbNail; // Don't like image in front of record.
[cell.textLabel setFont:[UIFont
fontWithName:#"Helvetica Neue" size:18]];
[cell.detailTextLabel setFont:[UIFont fontWithName:#"Helvetica Neue" size:16]];
[cell.detailTextLabel setTextColor:[UIColor grayColor]];
// make selected items orange
if ([athleteMarks.eventPR integerValue] != 0
&& (![exceptions containsObject:athleteMarks.markInEvent])) {
title = [NSMutableString stringWithFormat:#"%# (PR)",title];
[cell.textLabel setTextColor:[UIColor redColor]];
}
else if ([athleteMarks.eventSB integerValue] != 0
&& (![exceptions containsObject:athleteMarks.markInEvent])) {
title = [NSMutableString stringWithFormat:#"%# (SB)",title];
[cell.textLabel setTextColor:[UIColor orangeColor]];
} else {
[cell.textLabel setTextColor:[UIColor grayColor]];
}
cell.textLabel.text = title;
cell.detailTextLabel.text = subTitle;
cell.indentationLevel = indentationLevelOne;
cell.indentationWidth = indentationForCell;
return cell;
}
If you want, I can send you an example of a Category for an Entity's NSManagedObject Sub-Class. This Category loads the photo and the thumbnail into CoreData Entity. The first time will be slow. However, after that the user should be able to scroll through TableView smoothly and then all the updated results will load automatically. Let me know.
One nice thing is that CoreData handles all the memory management.
Good luck!
I don't have enough rep to comment, So here's an answer which helped my tableview scrolling performance:
Make the tableview height larger than the viewable window. Cells will load "off screen" and helps improve scroll smoothness.
Do your image processing in the following method:
-(void)tableView:(UITableView *)tableView
willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
Those two tricks got my table flowing really nice. I'm getting my image data from an API service and AFNETWORKING has an awesome image loader, but not necessary for you since images are in the bundle.
Maybe you could try SDWebImage instead. It is also a xamarin component
which fashions an asynchronous image downloader and asynchronous memory and disk image caching with automatic cache expiration handling. Using it would probably mean throwing away a lot of hard written code, but it might be worth it -plus your code will become a lot simpler. In iOS you can also setup a SDWebImageManager inside the viewDidLoad of a controller:
- (void)viewDidLoad{
...
SDWebImageManager *manager = [SDWebImageManager sharedManager];
manager.delegate = self;
...
}
and set the view controller as the delegate. Then, when the following delegate method is called:
- (UIImage *)imageManager:(SDWebImageManager *)imageManager transformDownloadedImage:(UIImage *)image withURL:(NSURL *)imageURL
you could scale your images to thumbs of the appropriate size before caching them.
Hope that helps.
Weel I had a similar problem, my scroll was not smooth. I am inserting in the table a variable UIImageView with inside labelViews.
What I did was to change the method HeightforRowAtIndexPath for estimatedHeightforRowAtIndexPath and now scroll is smooth.
How are you all. I'm having a weird issue with my tableviewcell. When I runn this on Simulator. It shows proper layout as in image 1.
but when I run this on device. It has colored lines in it on all tableviews of app, like image 2.
Is this something with iOS 7? I've cleared background color of cell in tablview:willDisplayCell:.
Code is
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
BarsCustomCell *cell= [BarsCustomCell resuableCellForTableView:tableView withOwner:self];
Bars *currentValue= [self.data objectAtIndex:indexPath.row];
if(indexPath.row==(self.data.count-1)){
[cell updateWithBars:currentValue isLast:YES isFirst:NO] ;
}else if (indexPath.row==0){
[cell updateWithBars:currentValue isLast:NO isFirst:YES] ;
}else{
[cell updateWithBars:currentValue isLast:NO isFirst:NO] ;
}
}
and Tableviewcell sublcassm method for updating.
-(void) updateWithBars:(Bars *)bars isLast:(BOOL)isLast isFirst:(BOOL)isFirst{
self.nameLbl.text= bars.name;
self.addressLbl.text= bars.vicinity;
double distance = [[[LOTVLocationManager sharedManager] mockedLocation] distanceFromLocation:bars.location];
self.distanceLbl.text= [NSString stringWithFormat:#"%.2f km",distance/1000];
if(isFirst){
self.bgImageview.image= [UIImage imageNamed:#"sport_top_bg.png"];
self.nameLbl.center= CGPointMake(self.nameLbl.center.x, self.nameLbl.center.y+3);
}
else if(isLast){
self.bgImageview.image= [UIImage imageNamed:#"sport_bottom_bg.png"];
self.addressLbl.center= CGPointMake(self.addressLbl.center.x, self.addressLbl.center.y-3);
}
}
Resolved the issue. It was due to TableviewCell's background color. Some iOS Versions support cell.backgroundColor and some support only cell.contentView.backgroundColor. I wrote both for cell and contentView to fix the issue.
I have an UITable with just 6 custom cells. Each CustomCell have a horizontal scroll view which have custom Views into it. Each CustomView has a ImageView and Text on it.
So to put it all together it may look like this
UITable --> CustomCell ---> Horizontal ScrollView --> CustomView --> ImageView and Text
Here is the code for Cell in UITable
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *MySecondIdentifier = #"MySecondIdentifier";
UITableViewCell *cell2 = [tableView dequeueReusableCellWithIdentifier:MySecondIdentifier];
if(cell2 == nil){
cell2 = [(CustomCell* )[CustomCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:MySecondIdentifier target:self row:indexPath.row parent:self];
}
[cell2 setSelectionStyle:UITableViewCellSelectionStyleNone];
[cell2 setValueToCellViewItem:tempTitleString setOfImage:dictCatData];
return cell2;
}
where DictCatData = NSMutableArray of data nodes
and tempTitleString = Title string for the cell (using it for some other purpose)
Here is how I set a CustomCell values
- (void) setValueToCellViewItem:(NSString *)pTitle setOfImage:(NSMutableArray *)catData{
[the_pScrolView setContentSize:CGSizeMake([catData count] * 107 , 107)];
int counter = 0;
for(NSDictionary *tempDict in catData){
NSString *url = [[NSString alloc]init];
url = [tempDict objectForKey:#"main_img_url"];
url = [url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
UIImageView *mSdWebImage = [[UIImageView alloc] initWithFrame:CGRectMake(counter * 107, 0, 107, 107)];
[mSdWebImage setImageWithURL:[NSURL URLWithString:url] placeholderImage:nil];
[mSdWebImage setBackgroundColor:[UIColor grayColor]];
[the_pScrolView addSubview:mSdWebImage];
///Setting the title properties
UILabel *the_pLable = [[UILabel alloc] initWithFrame:CGRectMake((counter * 107) + 15, 85, 97, 22)];
the_pLable.textColor = [UIColor whiteColor];
the_pLable.font = [UIFont fontWithName:#"Helvetica" size:10.0];
the_pLable.numberOfLines = 1;
the_pLable.backgroundColor = [UIColor clearColor];
the_pLable.text = [tempDict objectForKey:#"title"];
[the_pScrolView addSubview:the_pLable];
counter++;
}
I am using SDWebImage for async downloading and caching as I think thats the best we have on net.
The ScrollView can contain images ranging from 0 to 30+ images
When I open this page on my iPhone, the images are getting downloaded an cached properly I guess, as I am able to see them with no difficulties
My Problem are
When I try to scroll up and down the table, the scrolling is not smooth. So how can I make it more smoother without effecting the background image downloading and caching
When I scroll the table up and down several times, the custom cells are redrawn I guess so the CustomCells with no images (i.e. no customViews in scrollView) show the images from other custom cells below/top.
Sometimes the app crashes, I guess this is issue of memory management.
How big are the images being downloaded? I had similar issues (without the extra horizontal scrolling) and I was able to fix it by using actual thumbnails of the images instead of the actual images (in the TableView).
You may want to try downloading, caching, and creating thumbnails of the images in a separate object and then letting the TableViewCell load those thumbnails of the images instead of the actual images.
This sped up scrolling perfectly for me.
To fix the reused cells showing wrong images, simply remove the images in cellForRowAtIndexPath before calling your code to display new images. That way if the images are delayed, at least the old ones have been removed or hidden.
I have a custom cell,and it has a image in it..and I am accessing that image in this way
in
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
[[tableCell specialImage] setImage:[UIImage imageNamed:#"One.png"]];
}
So now I want to know how can i get the hieght and width of this "special image"..
Waiting for your reply
I think you are searching for that size:
CGRect size = [tableCell specialImage].bounds.size;
As per comments, I'd expect the following to work:
CGSize specialImageSize = [[tableCell specialImage] size];
If that doesn't work, you'll need to post more code for more help. For example, if the above doesn't work, it'd be helpful to know more about what I assume is a UITableViewCell subclass pointed to by tableCell.
Please try below code:
UIImage *imageThatIsSpecial = [UIImage imageNamed:#"One.png"];
NSLog(#"Image height is %f and its width is %f",imageThatIsSpecial.size.height, imageThatIsSpecial.size.width);
[[tableCell specialImage] setImage:imageThatIsSpecial];