UIScrollView updating/loading wrongly

Question

Im making a preview in my ViewController that all my Picked images in imagePicker will be in my scrollView, Yes, I was able to make a preview of it in thumbnail, But when I'm logging it in my debugger, it seems to be that everytime my viewDidAppear, it also reAdds the scrollView, so the images count is being added again, making it harder to delete in view due to overlaping of the images. What I needed is to just refresh the scrollview whenever the view appears and when I'm adding a new image/s.

Here is a sneak preview of those codes I'm having problems for a long time:

- (id) initWithCoder:(NSCoder *)aDecoder {
    if ((self = [super initWithCoder:aDecoder])) {
        _images =  [[NSMutableArray alloc] init];
        _thumbs =  [[NSMutableArray alloc] init];
    }
    return self;
}
- (void)addImage:(UIImage *)image {
    [_images addObject:image];
    [_thumbs addObject:[image imageByScalingAndCroppingForSize:CGSizeMake(60, 60)]];
    [self createScrollView];
}        
- (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)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];
}


- (void)viewDidAppear:(BOOL)animated
{    
    [_thumbs removeAllObjects];
    for(int i = 0; i <= 100; i++) 
    { 
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDir = [paths objectAtIndex:0];

        NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:@"Images%d.png", i]]; 
        if([[NSFileManager defaultManager] fileExistsAtPath:savedImagePath]){ 
            [self addImage:[UIImage imageWithContentsOfFile:savedImagePath]]; 
        } 
    }
}

Help would be much appreciated.

And would using this be much of help, removing then adding. Or is this a way to just completely remove/delete all those subview completely, then REadd? Thanks for those whose gonna help.

And could this be helpful? Thankyou

for(UIView *subview in [scrollView subviews]) {
    if([subview isKindOfClass:[UIView class]]) {
        [subview removeFromSuperview];
    } else {

    }
}    

DELETE:

- (void)deleteItem:(id)sender {
        _clickedButton = (UIButton *)sender;
        UIAlertView *saveMessage = [[UIAlertView alloc] initWithTitle:@""
                                                              message:@"DELETE？"
                                                             delegate:self
                                                    cancelButtonTitle:@"NO"
                                                    otherButtonTitles:@"YES", nil];
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    NSString *title = [alertView buttonTitleAtIndex:buttonIndex];
if([title isEqualToString:@"YES"]) {
        NSLog(@"YES was selected.");
            UIButton *button = _clickedButton;
            [button removeFromSuperview];
            [_images objectAtIndex:button.tag];
            [_images removeObjectAtIndex:button.tag];
            [_images removeObject:button];

            NSFileManager *fileManager = [NSFileManager defaultManager];
            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentsDirectory = [paths objectAtIndex:0];
            NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"Images%lu.png", button.tag]];
            [fileManager removeItemAtPath: fullPath error:NULL];
            NSLog(@"image removed");
    }
}

Answer 1

Here is a working example : Google Code

I wrote out the code, and I have this. It will align the view to be 5 wide, and however tall it has to be, and the scrollview will change height.

You will need to create a new NSMutableArray named _buttons that will contain a list of your buttons.

- (void)addImage:(UIImage *)imageToAdd {
    [_images addObject:imageToAdd];
    [_thumbs addObject:[imageToAdd imageByScalingAndCroppingForSize:CGSizeMake(60, 60)]];

    int row = floor(([views count] - 1) / 5);
    int column = (([views count] - 1) - (row * 5));

    UIImage *thumb = [_thumbs objectAtIndex:[_thumbs count]-1];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(column*60+10, row*60+10, 60, 60);
    [button setImage:thumb forState:UIControlStateNormal];
    [button addTarget:self action:@selector(deleteItem:) forControlEvents:UIControlEventTouchUpInside];
    button.tag = [views count] - 1;
    // This is the title of where they were created, so we can see them move.s
    [button setTitle:[NSString stringWithFormat:@"%d, %d", row, column] forState:UIControlStateNormal];

    [_buttons addObject:button];
    [scrollView addSubview:button];
        // This will add 10px padding on the bottom as well as the top and left.
    [scrollView setContentSize:CGSizeMake(300, row*60+20+60)];
}

- (void)deleteItem:(id)sender {
    UIButton *button = (UIButton *)sender;
    [button removeFromSuperview];
    [views removeObjectAtIndex:button.tag];
    [_buttons removeObjectAtIndex:button.tag];

    [self rearrangeButtons:button.tag];
}

- (void)rearrangeButtons:(int)fromTag {
    for (UIButton *button in _buttons) {
        // Shift the tags down one
        if (button.tag > fromTag) {
            button.tag -= 1;
        }
        // Recalculate Position
        int row = floor(button.tag / 5);
        int column = (button.tag - (row * 5));
        // Move
        button.frame = CGRectMake(column*60+10, row*60+10, 60, 60);
        if (button.tag == [_buttons count] - 1) {
            [scrollView setContentSize:CGSizeMake(300, row*60+20+60)];
        }
    }
}

Note: In the rearrangeButtons method, it is possible to animate the changes.

Here is the code to rearrange the files:

- (void)rearrangeButtons:(int)fromTag {
    for (UIButton *button in _buttons) {
        // Shift the tags down one
        if (button.tag > fromTag) {
            // Create name string
            NSString *imageName = [NSString stringWithFormat:@"images%i.png", button.tag];
            // Load image
            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentFile = [paths objectAtIndex:0];
            NSSting *oldFilePath = [documentFile stringByAppendingPathComponent:imageName];
            NSData *data = [[NSData alloc] initWithContentsOfFile:oldFilePath];
            button.tag -= 1;
            // Save the image with the new tag/name
            NSString *newImageName = [NSString stringWithFormat:@"images%i.png", button.tag];
            NSString *newFilePath = [documentFile stringByAppendingPathComponent:newImageName];
            [data writeToFile:newFilePath atomically:YES];
            // Delete the old one
            NSFileManager *fileManager = [NSFileManager defaultManager];
            NSError *err = nil;
            if (![fileManager removeItemAtPath:file error:&err]) {
                // Error deleting file
            }
        }
        // Recalculate Position
        int row = floor(button.tag / 5);
        int column = (button.tag - (row * 5));
        // Move
        button.frame = CGRectMake(column*60+10, row*60+10, 60, 60);
        if (button.tag == [_buttons count] - 1) {
            [scrollView setContentSize:CGSizeMake(300, row*60+20+60)];
        }
    }
}