ScrollView not updated with imageview - ios

Question

I have 20 images in my main bundle and i want to display it in my scroll view horizontally.
I am doing it successfully but now the problem is images are visible in scrollview after all imageview are set in scroll view and it takes time.
For resolve that I create one nsoperation.
-(BOOL)sync:(NSError**)error
{
float imageLeftPosition = 0;
for (int imageCount = 1; imageCount<=syncObject.syncNumberOfImages; imageCount++) {
UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(imageLeftPosition, 0, syncObject.syncImageWidth, syncObject.syncImageHeight)];
[imgView setImage:[UIImage imageNamed:[NSString stringWithFormat:#"%d_%d.jpg",syncObject.syncChapterNumber,imageCount]]];
imgView.tag = imageCount;
// NSDictionary *dictionary = [NSDictionary new];
//
// [dictionary setValue:imgView forKey:CHAPTER_IMAGE];
imageLeftPosition = imageLeftPosition+syncObject.syncImageWidth;
//[dictionary setValue:[NSString stringWithFormat:#"%f",imageLeftPosition] forKey:CHAPTER_SCROLL_LEFT_POSITION];
NSDictionary *dictionary = [[NSDictionary alloc] initWithObjects:[NSArray arrayWithObjects:imgView,[NSString stringWithFormat:#"%f",imageLeftPosition], nil] forKeys:[NSArray arrayWithObjects:CHAPTER_IMAGE,CHAPTER_SCROLL_LEFT_POSITION, nil]];
[self sendNotification:dictionary];
imgView = nil;
dictionary = nil;
}
return YES;
}
what i am doing here is add create one image view and post it to main view using notification
-(void)addImageView:(NSNotification*)notification
{
NSInteger thread = [NSThread isMainThread]?CVC_MainThread:CVC_BackgroundThread;
switch (thread) {
case CVC_MainThread:
{
NSDictionary *dictionary = notification.userInfo;
if(dictionary != nil)
{
NSLog(#"image view : %#",(UIImageView*)[dictionary valueForKey:CHAPTER_IMAGE]);
NSLog(#"leftposition: %f",[[dictionary valueForKey:CHAPTER_SCROLL_LEFT_POSITION] floatValue]);
[_scrChapters addSubview:((UIImageView*)[dictionary valueForKey:CHAPTER_IMAGE])];
_scrChapters.contentSize = CGSizeMake([[dictionary valueForKey:CHAPTER_SCROLL_LEFT_POSITION] floatValue], 0);
}
dictionary = nil;
}
break;
case CVC_BackgroundThread:
{
dispatch_async(dispatch_get_main_queue(), ^(void) {
NSDictionary *dictionary = notification.userInfo;
if(dictionary != nil)
{
NSLog(#"image view : %#",(UIImageView*)[dictionary valueForKey:CHAPTER_IMAGE]);
NSLog(#"leftposition: %f",[[dictionary valueForKey:CHAPTER_SCROLL_LEFT_POSITION] floatValue]);
[_scrChapters addSubview:((UIImageView*)[dictionary valueForKey:CHAPTER_IMAGE])];
_scrChapters.contentSize = CGSizeMake([[dictionary valueForKey:CHAPTER_SCROLL_LEFT_POSITION] floatValue], 0);
}
dictionary = nil;
});
}
break;
default:
break;
}
}
this is the notification handler method where i set the content size and image view in scroll view for each loop on main thread still scroll view are visible after all the images are load.
What I am doing wrong?

Answer 1

Try to use pagedflowview. This will load only the visible items into the Scrollview and is easy to customize. You can also search for iCarousel.
https://www.cocoacontrols.com/controls/pagedflowview

Answer 2

Try this
-(void)showimagesasSlide:(int) totalimagesCount
{
int xAxisofimageView=0;
for (int initialimagesCount=0;initialimagesCount<totalimagesCount; initialimagesCount++) {
UIImageView *detailedImageview=[[UIImageView alloc] init];
detailedImageview.userInteractionEnabled=YES;
UIImage *dynamicImage=[ScaleImageSize squareImageWithImage:[images objectAtIndex:initialimagesCount] scaledToSize:CGSizeMake(300, 500) ];
if (IS_IPHONE_5) {
detailedImageview.frame=CGRectMake(xAxisofimageView, 0, 320, 568);
}
else
{
detailedImageview.frame=CGRectMake(xAxisofimageView, 0, 320, 460);
}
// detailedImageview.contentMode=UIViewContentModeCenter;
detailedImageview.backgroundColor=[UIColor clearColor];
detailedImageview.image=dynamicImage;
detailedImageview.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin|UIViewAutoresizingFlexibleRightMargin ;
detailedImageview.tag=initialimagesCount+12;
[mainScrollview addSubview:detailedImageview];
xAxisofimageView=xAxisofimageView+320;
}
mainScrollview.contentSize=CGSizeMake(320*images.count, 0);
}