I have search the web many times for the same question and also got many relavent answers but none of them resolved my problem.
Here is the problem: I am having a UITableView with UISearchBar on its top.As the users searches for particular word,the UITableView is filled with custom cells.
It works fine in the simulator.The problem is with the device,I mean iPad.
Now when the tableview is having almost 40-50 cells,it works fine even when the user scrolls. But if the tableView contains 60+ cells and user scrolls to,say 55 onwards,app crashes without giving any error. I have set NSZoombie Enabled. I have already debugged the app many times but no results.
profile your app and see if you use too much memory or not.
also you can see memory warnings from applicationDidReceiveMemoryWarning method of your appdelegate, just implement it and put a breakpoint to the entrance.
if there is a problem with reusing of the cells, you might be allocating too much cells and exceeding the memory limits.
Related
AM using a UIActivityIndicator view as a UITableViewFooter, works fine in simulator, but shows different behavior in devices,think that occurs due to OS change.
Sometimes it fits to the width of the screen and seems enlarged, in other cases simply disappears, Any solution?
Found the reason myself, adding UIActivityIndicator as footer causes trouble in certain devices, so its better to use text like "Loading..."if you still need to show a footer.Else add an extra cell to UITableView and add UIActivityIndicator to that last cell.
In my case, the error was while testing in 3GS, no trouble in other devices.
Regards
I have a UITableView with some data. One of controls is a UIButton, with a label assigned. So, in rare cases, when I push the UITableView screen, the buttons appears without label. After I scroll the UITableView or rotate the device, the label appears.
I put a NSLog entry inside the drawRect method. And It's not called in some cases.
Some advices?
Thanks
i found same problems that some methods rarely not called. make sure delegate is properly set and then check the result
After analyzing my code I saw some characteristic that caused the problem. The process of construction of my screen was occurring in a different thread of the events thread. So, I fixed this and everything is fine now.
Thanks.
I am working on an iPad app that lets the user scroll through a number of images (usually around 20 .jpg files in a single horizontal scroll view). The file sizes are around 200 kb each. The images are set as the "Background" property of a UIButton because I wanted to allow the user to click the button to save the image. Every time I run the app, it crashes after scrolling for a little while. If you don't scroll, it behaves normal. I did run the app using the performance tools and didn't find any leaks.
I am getting a "Level=1" memory warning just before the app crashes. I had it running with about 8 images in the scrollview and never had a problem. So I know it has something to do with the scrollView and the images/buttons. In the "viewDidLoad" method, I simply did the following to set up the scrollView and then linked it in Interface Builder:
[scrollView setContentSize:CGSizeMake(5722, 340)];
[scrollView setScrollEnabled:YES];
[scrollView setDelaysContentTouches:YES];
Any ideas on how to get this to work? I added the images directly to the button in Interface Builder. Would it help if I deleted the background image, and instead set the backgrounds in the "viewDidLoad" method? Any help would be appreciated.
Sounds like what you need to do is create individual cells that these images live on, that get recycled like you'd get in a tableview. I have some code which does this that you may use for your purpose, or at least give it a go anyway. Works just like a tableview.
It's available here. This does the heavy lifting for you already, in that all you need to do is create one of these, slap it in a view somewhere, and create your individual cells. Those cells will be reused as you scroll so you won't need more than N + 2 cells loaded into memory at any one time, where N is the number that fit on your screen.
as jer wrote, the problem seems to be in the recycling. Make sure to remove, release and update the content of each cell every time you get a new one in tableView:cellForRowAtIndexPath:
(I would have commented jer's post but I'm unable to do this, probably because of my limited permissions).
I have a tabBar in my application. In one of the section i have two views which i toggle between using segment buttons.
In one of the view i have MapView which i use to display list of users using their pic as annotation. On the other view i have tableView which shows the same users in table format.
Now everything is working fine, i am getting all the users and it displays fine on the map. It works perfectly most of the time on all device and all iOS but sometimes when i bring the mapView to front or toggle or try to zoom in. Both the views (tableView and mapView) just gets removed somehow and i see black screen (which is btw my superview so thats not a problem).
Does anyone know why this happens. It happens frequently on iPhone 3G the older iPhone.
Thanx for any help.
I've had the same problem. I think it's due to low memory to which your app responds by deallocating the tableView and mapView. My solution was to have both views allocated in viewDidLoad. I'm not 100% sure about this, but you could give it a try.
I'm new to iPhone development. I'm working on a table view (default UITableView subclass) that contains complicated custom cells, with multiple subviews and controls. Scrolling is not very smooth, but I'll just leave that for now.
The question is, when I'm scrolling the table view with quick swipes, the table sometimes suddenly stops scrolling and the scroll indicator will not disappear, and I have to swipe again to make it scroll.
If the table contains very few rows, say, 5 or 6, it never stuck. The custom cell class I used is from the example provided here: http://blog.atebits.com/2008/12/fast-scrolling-in-tweetie-with-uitableview/
Can anyone give a hint or solution to this problem? Thanks in advance.
Table cells are only created when needed, that is when they come into view and they are usually unloaded and released when they go out of view.
Put in an NSLog( #"Cell loading" ); in your cell creation code and check the console to see this happen as you scroll.
Are you using caching? The docs demonstrate how you can cache table cells to improve performance. What else are you doing when you're creating table cells? If there's any performance slow downs you should probably not have that happen while creating cells.
What I do is I generate all my content before the table loads and when cells are created all that content is simply placed into the view.
Any kind of drawing will drastically reduce performance especially if you're using transparency.
For posterity, and only valid if you are using Unity-iphone: this problem was driving me insane and I fixed it with the suggestion in this post:
http://forum.unity3d.com/threads/113815-quot-Sticky-quot-scrolling-in-UITableView-and-UIScrollView-when-interfacing-Unity-and-Obj-C
Changing the preprocessor flag to
#define USE_DISPLAY_LINK_IF_AVAILABLE 0
gave the issue a happy ending.
I'd take a look at your cellForRowAtIndexPath method - for a couple of possible problems.
If you aren't using the cell reuse that will slow things down a lot and if you are re-allocating or re-initializing your custom cells in the cellForRowAtIndexPath delegate method that can cause big performance issues.
If you post your code for that method we can give you some hints as to what might be causing it.