UIScrollView not loading/updating properly - iphone

Question

Im having problem with my UISCrollView, UIScrollVIew is in my View2Controller, my UIScrollView has thumbnail of images, which I imported from my ImagePicker picked images(multiple/single images). I have put my [self createScrollView]; in viewDidAppear, So at my first load of the view only the UIScrollView, obviously because I havent picked images yet. So after I picked its not updating in my view. But my images.count are updating in the my debugger. It's not updating in View, but when I go to another ViewController then return again to View2Controller, it loads the images in my UIScrollView,then when I add again images it's not updating. Why is it like that?.
- (void)addImage:(UIImage *)image {
[_images addObject:image];
[_thumbs addObject:[image imageByScalingAndCroppingForSize:CGSizeMake(60, 60)]];
}
- (void) createScrollView {
[scrollView setNeedsDisplay];
int row = 0;
int column = 0;
for(int i = 0; i < _thumbs.count; ++i) {
UIImage *thumb = [_thumbs objectAtIndex:i];
UIButton * button = [UIButton buttonWithType:UIButtonTypeCustom];
button.frame = CGRectMake(column*60+10, row*60+10, 60, 75);
[button setImage:thumb forState:UIControlStateNormal];
[button addTarget:self
action:#selector(buttonClicked:)
forControlEvents:UIControlEventTouchUpInside];
button.tag = i;
[scrollView addSubview:button];
if (column == 4) {
column = 0;
row++;
} else {
column++;
}
}
[scrollView setContentSize:CGSizeMake(300, (row+1) * 60 + 10)];
}
- (void)viewDidAppear:(BOOL)animated
{
[self createScrollView];
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.slotBg = [[UIView alloc] initWithFrame:CGRectMake(43, 370, 310, 143)];
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = self.slotBg.bounds;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor grayColor] CGColor], (id)[[UIColor whiteColor] CGColor], nil];
[self.slotBg.layer insertSublayer:gradient atIndex:0];
[self.view addSubview:self.slotBg];
self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0.0f,0.0f,300.0f,130.0f)];
[slotBg addSubview:self.scrollView];
for(int i = 0; i <= 100; i++)
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:#"oneSlotImages%d.png", i]];
NSLog(#"savedImagePath=%#",savedImagePath);
if([[NSFileManager defaultManager] fileExistsAtPath:savedImagePath]){
[self addImage:[UIImage imageWithContentsOfFile:savedImagePath]];
NSLog(#"file exists");
}
}
NSLog(#"Count : %d", [_images count]);
}
EDIT: (In this part, the image can't be deleted from the view. But in my NSDocumentDirectory it is deleted, )
- (IBAction)buttonClicked:(id)sender {
_clickedButton = (UIButton *)sender;
UIAlertView *saveMessage = [[UIAlertView alloc] initWithTitle:#""
message:#"DELETE IMAGE？"
delegate:self
cancelButtonTitle:#"NO"
otherButtonTitles:#"YES", nil];
[saveMessage show];
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
NSString *title = [alertView buttonTitleAtIndex:buttonIndex];
if([title isEqualToString:#"YES"]) {
NSLog(#"YES was selected.");
UIButton *button = _clickedButton1;
[button removeFromSuperview];
[_images1 objectAtIndex:button.tag];
[_images1 removeObjectAtIndex:button.tag];
NSFileManager *fileManager = [NSFileManager defaultManager];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:#"firstSlotImages%lu.png", button.tag]];
[fileManager removeItemAtPath: fullPath error:NULL];
NSLog(#"image removed");
}

Answer 1

viewDidAppear: is only called once you go to a view. So when you are 'adding' the images you are only adding them to the _images array, they are not displayed because you are not adding them to the screen. They are displayed when you leave the view and come back because viewDidAppear: is called again.
To fix this, use addImage: to also add it to the current view.
- (void)addImage:(UIImage *)image {
int row = ?;
int column = ?;
[_images addObject:image];
[_thumbs addObject:[image imageByScalingAndCroppingForSize:CGSizeMake(60, 60)]];
UIImage *thumb = [_thumbs objectAtIndex:_thumbs.count-1];
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
button.frame = CGRectMake(column*60+10, row*60+10, 60, 75);
[button setImage:thumb
forState:UIControlStateNormal];
[button addTarget:self
action:#selector(buttonClicked:)
forControlEvents:UIControlEventTouchUpInside];
button.tag = _thumbs.count-1;
[scrollView addSubview:button];
}
Only problem of course is how to determine the placement, aka column and row. You can do this by getting the last thumb's frame and figuring out where to place it according to screen bounds.
Another Fix
- (void)addImage:(UIImage *)image {
[_images addObject:image];
[_thumbs addObject:[image imageByScalingAndCroppingForSize:CGSizeMake(60, 60)]];
[self createScrollView];
}

Answer 2

You need to call createScrollView after you have updated your array of images. Maybe try moving [self createScrollView]; to the end of your viewDidLoad method? Either way, you need to call createScrollView after you have added all of your images.