In my application i m using webservices to get the the image to load in UITableView. the images loaded in the cell and i scroll down to see other datas, if i again scroll up to see already loaded data, there the loaded images are again loading.
Why this happens. can anyone tell that how to display images in LazyTableImage example
If we scroll, each time cellForRowAtInpdex is called every time.so,you should handle the image loading in someother part(say ViewDidLoad)..
Related
I have a UITableView with images like photo album, images are loading with lazy loading. I want to load more images while scrolling to the bottom of the tableview or when the last row of the table view reached. How can I do this?
UITableView already does lazy loading for you. It will only ask for the visible cells. If you are taking about adding more images to the table while the user is scrolling, you can implement UIScrollViewDelegate methods to calculate the current scrolling position, and when the user reaches certain point, add more images to the NSMutableArray on your datasource.
Check this
http://developer.apple.com/library/ios/#samplecode/LazyTableImages/Introduction/Intro.html
and this Lazy load images in UITableView
You can use SDWebImage.
This library provides a category for UIImageVIew with support for remote images coming from the web.
It provides:
An UIImageView category adding web image and cache management to the Cocoa Touch framework
An asynchronous image downloader
An asynchronous memory + disk image caching with automatic cache expiration handling
A guarantee that the same URL won't be downloaded several times
A guarantee that bogus URLs won't be retried again and again
Performances!
i have photo gallery which loaded to scroll view vertically and i only want to load visible pages to avoid memory issues like table views did. Is there a way to do this? i am using core data to get images and there are more than 150+ images in it.
I used this: http://www.markj.net/iphone-asynchronous-table-image/ and I'd think it would help in your scenario as well
if you are using vertical only scroll you may use UITableView with custom UITableViewCell.
This way, you get the lazy load done.
When I scroll to new area of the UITableView with lazy image loading, then
immdietly scroll back to the old area, no matter what I do now, the new area will not show new images.
My code is based on apple lazy table view.
Till now I thought it was something with the web server, but I had cache functionality now, and all images are loaded from iphone files, so for sure there is somthing wrong in my code.
Again, the images are not shown ONLY in that case :
UITableView is loading the data
All visible cell are showing the images correctly.
If I scroll to new area, move to old area *quickly* and move back to new area the image will not load, no matter where I scroller now(only the images in the new area that I quickly scorll back from will not load)
all on other cases, the images are shown correctly.
Without seeing the some code its hard to say. If your display is tied to a callback from the NSURLConnection you might be losing your reference to the delegate.
When you scroll the cell view get repopulated with the data in the new cell. If the NSURLConnection is running outside of the cell view you might be losing the reference to it's delegate. When the NSURLConnection is completed if it doesn't have a delegate to fire the complete method then it won't get called. When you scroll to the new cell the NSURLConnection is already complete so it doesn't call the completed again and the spinner just keeps going.
I fix it. the bug was nothing to do with all above. so nothing to share and learn from.
I thought it is important for other I'll be clear about that, so no one will be confused about what I wrote earlier.
The process of checking if image already download was wrong.
Greetings of the day.
I am having table view where JSON data having text,distance and image is loading very slowly in cells,as i am scrolling down app is getting heavy... but i had seen in some apps that irrespective of image data.... text and distance has been loaded earlier and by activity indicator they are showing that image is loading.
I am not getting how to scroll faster in table view irrespective of image data.
thanx in advance
Software Developer
You may want to read this Apple doc about loading table view cells. I also am loading a UITableView from JSON web data, but what was really slow was the handling and loading of the table cell objects themselves.
It scrolled noticeably faster once I worked in the Apple-recommended cell handling code.
I am displaying 200 thumb nail images of size 4kb to 12kb in UIScrollView programmatically by adding UIButton when i am debugging in device it takes time to load the view.. can there is some method to load quickly the thumb mages are store in disk.
Use lazy loading by only loading the ones you show at once in any given moment - or use a background thread to perform the loading while keeping the interface responsive.
If your layout allows, use a table view and a custom cell that holds several thumbnails. That way you can use the tableview controller's built in methods to manage the lazy loading. I'm pretty sure that is how Apple does the thumbnails in the photo library.