I am working with an Objective-C application that features a scene with a full screen horizontally scrolling UICollectionView. I currently have a function being called every time a new cell appears on screen during scrolling that takes about 3-4 seconds to run and edits ui elements within the newly appeared cell. Because of this, my app lags every time a new cell enters the screen for about 4 seconds and then continues to scroll normally.
Is there a way to edit this function and put it on a background thread so that instead of a a 4 second lag in scrolling, there is seamless, uninterrupted scrolling? I understand that this solution will cause a 4 second delay to the ui elements from appearing but I am fine with that as long as there is a seamless scroll.
EDIT: I didn't think it would be a good idea to post code for this problem since the code in function that does the loading requires a video player api that I purchased, but I will go ahead and post the method below to show what parts of the function edit the UI.
//variables declared in other parts of the file
KolorEyes *myKolorEyesPlayer;
UICollectionView *collectionViewFollwersFeed;
NSIndexPath *lastPath = nil;
//called repeatedly while scrolling
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
if(scrollView==_collectionViewFollwersFeed)
{
[self tsLoad]; //function call
}
}
- (void)tsLoad {
//calculate index path of cell in the center of the screen
NSIndexPath *centerCellIndexPath =
[self.collectionViewFollwersFeed indexPathForItemAtPoint:
[self.view convertPoint:[self.view center] toView:self.collectionViewFollwersFeed]];
if(centerCellIndexPath != lastPath) //condition is satisfied if a new cell has been scrolled to the center
{
lastPath = centerCellIndexPath;
UICollectionViewCell *cell;
NSString *CellIdentifier;
//initialize cell from center path
CellIdentifier = @"FollowersFeed";
cell = [_collectionViewFollwersFeed cellForItemAtIndexPath:centerCellIndexPath];
//get respective url for video player
NSMutableDictionary *dict1=[follwerFeed objectAtIndex:centerCellIndexPath.row];
NSString *tsstring= [dict1 valueForKey:@"video"];
NSURL *tsurl = [[NSURL alloc] initWithString:tsstring];
//view that the video will be played in
UIView *tsView = (UIView *)[cell viewWithTag:99];
//API-specific parameters for video player session
KolorEyesSessionParams *params = [[KolorEyesSessionParams alloc] init];
params.delegate = self;
/* other params properties set like above at this point...
...
...
*/
//API-specific initialization
myKolorEyesPlayer = [[KolorEyes alloc] initWithParams:params];
//API-specific parameters for video player view
KolorEyesRenderViewParams *fparams = [[KolorEyesRenderViewParams alloc] init];
fparams.cameraFieldOfView = 90;
/* other fparams properties set like above at this point...
...
...
*/
//API-specific initializations
id _tsViewHandle = [myKolorEyesPlayer setRenderView: tsView withParams:fparams];
[myKolorEyesPlayer setCameraControlMode:kKE_CAMERA_MOTION forView:_tsViewHandle];
__block KolorEyes *player = myKolorEyesPlayer;
//error checking
eKEError err = [myKolorEyesPlayer setAssetURL: tsurl
withCompletionHandler:^{
// Media is loaded, play now
[player play];
}];
if (err != kKE_ERR_NONE) {
NSLog(@"Kolor Eyes setAssetURL failed with error");
}
}
}
