Trying to use visibleCells when scrolling UITableView in iOS - ios

Question

I am building an app where a UIImageView traverses a UITableView programmatically. I have created two buttons ("up" and "down") that control which direction the UIImageView moves. What I am trying to do is programmatically scroll the UITableView if the UIImageView is moving up/down to a row that is not presently visible. I realize I need to use the UITableView method, "visibleCells" to check to see if the cell is within the array is returned. If the cell is not in the array, then I need to scroll the table up/down by precisely one row (each time the user clicks on the "up"/"down" button). Unfortunately I have not come across any good examples on how to use the method, and I need help. Here is the code that I have here:
- (IBAction)buttonClicked:(id)sender {
if([sender tag] == 1){
//here is where I will need to make the call to [_tableView visibleCells] to see if the cell that the UIImageView is about to scroll up to is within this array. If not, then programmatically scroll up one row.
if (_index.row == 0) {
_index = [NSIndexPath indexPathForRow:[_tableData count] - 1 inSection:_index.section];
[_table scrollToRowAtIndexPath:_index atScrollPosition:UITableViewScrollPositionTop animated:YES];
}
else
_index = [NSIndexPath indexPathForRow:_index.row - 1 inSection:_index.section];
[UIView animateWithDuration:.3 animations:^{
CGRect rect = [self.view convertRect:[_table rectForRowAtIndexPath:_index] fromView:_table];
CGFloat floatx = _imageView.frame.origin.x - rect.origin.x;
_imageView.frame = CGRectMake(rect.origin.x + floatx, rect.origin.y, _imageView.frame.size.width, _imageView.frame.size.height);
}];
}
else if([sender tag] == 2){
if (_index.row + 1 == [_tableData count]) {
_index = [NSIndexPath indexPathForRow:0 inSection:_index.section];
[_table scrollToRowAtIndexPath:_index atScrollPosition:UITableViewScrollPositionBottom animated:YES];
}
else
_index = [NSIndexPath indexPathForRow:_index.row + 1 inSection:_index.section];
[UIView animateWithDuration:.3 animations:^{
CGRect rect = [self.view convertRect:[_table rectForRowAtIndexPath:_index] fromView:_table];
CGFloat floatx = _imageView.frame.origin.x - rect.origin.x;
_imageView.frame = CGRectMake(rect.origin.x + floatx, rect.origin.y, _imageView.frame.size.width, _imageView.frame.size.height);
}];
}
}
Can anyone show me how to accomplish the functionality that I am trying to achieve?

Answer 1

If you have a little bit time to learn something new, i recommend you to try with iCarousel by #nick-lockwood. Yo can use a vertical iCarousel to achieve something like that:
It's like a UITableView, but for each item in the carousel you can set any UIView, and then you can show a specific item setting the currentItemIndex property!
Take a look if it fits to you. iCarousel saved me two days of work!