Override automatic scrolling in UITextView? - iphone

Question

I have a view in a note-taking application I'm creating that is composed of a UITableView with a UITextView as a custom UITableViewCell (among other things). I know that having a UIScrollView within another UIScrollView is generally not recommended but I don't see a better way to do it for my purposes.
At any rate, the issue I'm having right now is that the UITextView, despite having scrolling disabled, is still affecting the scrolling of the UITableView itself. In other words, when I enter text into the UITextView or select it, the UITableView is scrolled automatically by the UITextView. Sometimes it works as desired, scrolling appropriately to the selected text, but more often than not it does not, generally scrolling to the bottom of the UITextView cell (which is not at all what I want). So I've been trying to handle the scrolling manually or finding a way to make it work automatically, but so far I've had no luck.
I've been searching for solutions here and on Google for days but I haven't come up with anything that works. I've tried simply scrolling to the desired area in the textViewDidBeginEditing method or by intercepting the UIKeyboardWillShowNotification notification, but neither produces the desired effect - the former scrolls after the UITextView has already automatically scrolled, the latter before (and so the automatic scrolling still occurs either way).
I've also tried subclassing the UITextView being used in the cell and overriding all scroll methods (ie. scrollRectToVisible), but this does not appear to prevent the automatic scrolling either. I've tried adjusting the frame of the UITableView when the UITextView is in use, which only made things worse.
So the conclusion I've come to is that I have to somehow disable all automatic scrolling in the UITextView, or prevent the two from communicating somehow. I've been trying to find a way to do this though and I haven't had any luck so far. Does anyone know how to do this or have an alternative solution to my issue? I'd really appreciate any help possible here.
Below is the code I think pertains to this issue. I'd be happy to provide any more if it helps. Also, this is my first iOS application, so forgive me if there is some poor technique in my code or if there is something I've overlooked.
UITableViewController:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell;
switch (indexPath.row) {
case 0:
cell = [self cellForTitleCell:indexPath withTableView:tableView];
break;
case 1:
cell = [self cellForBodyCell:indexPath withTableView:tableView];
break;
default:
cell = [self cellForListCell:indexPath withTableView:tableView];
break;
}
return cell;
}
- (UITableViewCell *)cellForBodyCell:(NSIndexPath *)indexPath withTableView: (UITableView *) tableView
{
static NSString *CellIdentifier = #"NoteViewBodyCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
NSString *bodyText = note.Body;
float frameHeight = [self tableView:tableView heightForRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0]];
frameHeight += self.navigationController.navigationBar.frame.size.height;
frameHeight += self.navigationController.toolbar.frame.size.height;
if (bodyTextView == nil)
{
bodyTextView = [[BodyTextView alloc] initWithFrame:CGRectMake(0, 0, 320, 460 - frameHeight)];
bodyTextView.font = [UIFont systemFontOfSize:17.0];
bodyTextView.text = bodyText;
bodyTextView.textColor = [UIColor blackColor];
bodyTextView.editable = YES;
bodyTextView.delegate = self;
bodyTextView.tag = 6;
CGSize bodySize = [bodyTextView.text sizeWithFont:bodyTextView.font
constrainedToSize:CGSizeMake(self.tableView.bounds.size.width-20, 9999)
lineBreakMode:UILineBreakModeWordWrap];
CGRect bodyFrame = bodyTextView.frame;
if (bodySize.height < 460 - frameHeight)
bodySize.height = 460 - frameHeight;
bodyFrame.size.height = bodySize.height;
bodyTextView.frame = bodyFrame;
bodyTextView.scrollEnabled = NO;
}
[cell.contentView addSubview:bodyTextView];
cell.frame = bodyTextView.frame;
bodyTextView.inputAccessoryView = keyboardToolbar;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
CGFloat rowHeight;
CGSize bodyTextSize;
switch (indexPath.row) {
case 0:
rowHeight = 40;
break;
case 1:
if ([self isStringEmpty:bodyTextView.text])
bodyTextSize = [note.Body sizeWithFont:[UIFont systemFontOfSize:17.0] constrainedToSize:CGSizeMake(self.tableView.bounds.size.width-20, 9999) lineBreakMode:UILineBreakModeWordWrap];
else
bodyTextSize = bodyTextView.contentSize;
if (bodyTextSize.height < 460 - 128)
rowHeight = 460 - 128;
else
rowHeight = bodyTextSize.height;
break;
default:
rowHeight = 40;
break;
}
return rowHeight;
}
- (void)textViewDidChange:(UITextView *)textView
{
[self.tableView beginUpdates];
[self.tableView endUpdates];
CGRect bodyFrame = bodyTextView.frame;
bodyFrame.size.height = bodyTextView.contentSize.height;
if (bodyFrame.size.height < 460 - 128)
bodyFrame.size.height = 460 - 128;
bodyTextView.frame = bodyFrame;
}
UITextView (subclass):
- (id)init
{
self = [super init];
if (self) {
// Initialization code here.
self.scrollEnabled = NO;
}
return self;
}
- (void) scrollRectToVisible:(CGRect)rect animated:(BOOL)animated
{
// do nothing
}
- (UIEdgeInsets) contentInset
{
return UIEdgeInsetsZero;
}
- (void)scrollRangeToVisible:(NSRange)range
{
// do nothing
}
- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated
{
// do nothing
}
- (BOOL) isScrollEnabled
{
return NO;
}
Some methods I've tried (found on StackOverflow):
// tried calling this method in both textViewDidBeginEditing and keyboardWillShow
- (BOOL)scrollToCursor
{
// if there is a selection cursor…
if(bodyTextView.selectedRange.location != NSNotFound)
{
NSLog(#"selectedRange: %d %d", bodyTextView.selectedRange.location, bodyTextView.selectedRange.length);
// work out how big the text view would be if the text only went up to the cursor
NSRange range;
range.location = bodyTextView.selectedRange.location;
range.length = bodyTextView.text.length - range.location;
NSString *string = [bodyTextView.text stringByReplacingCharactersInRange:range withString:#""];
CGSize size = [string sizeWithFont:bodyTextView.font constrainedToSize:bodyTextView.bounds.size lineBreakMode:UILineBreakModeWordWrap];
// work out where that position would be relative to the textView's frame
CGRect viewRect = bodyTextView.frame;
int scrollHeight = viewRect.origin.y + size.height;
CGRect finalRect = CGRectMake(1, scrollHeight, 1, 1);
// scroll to it
[self.tableView scrollRectToVisible:finalRect animated:YES];
return YES;
}
else
{
NSLog(#"NO CURSOR");
return NO;
}
}
- (void) keyboardWillShow:(NSNotification *)notification
{
if ([bodyTextView isFirstResponder])
{
NSLog(#"starting to change scroll view");
// Get the keyboard size
CGRect keyboardBounds;
[[notification.userInfo valueForKey:UIKeyboardFrameBeginUserInfoKey] getValue: &keyboardBounds];
// Detect orientation
UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
CGRect frame = self.tableView.frame;
// Start animation
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.3f];
// Reduce size of the Table view
if (orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown)
frame.size.height -= keyboardBounds.size.height;
else
frame.size.height -= keyboardBounds.size.width;
frame.size.height += keyboardToolbar.frame.size.height;
// Apply new size of table view
self.tableView.frame = frame;
// Scroll the table view to see the TextField just above the keyboard
if (self.bodyTextView)
{
CGRect textViewRect = [self.tableView convertRect:bodyTextView.bounds fromView:bodyTextView];
[self.tableView scrollRectToVisible:textViewRect animated:NO];
}
[UIView commitAnimations];
}
isKeyboardVisible = YES;
}
- (void) keyboardWillHide:(NSNotification *)notification
{
if ([bodyTextView isFirstResponder])
{
// Get the keyboard size
CGRect keyboardBounds;
[[notification.userInfo valueForKey:UIKeyboardFrameBeginUserInfoKey] getValue: &keyboardBounds];
// Detect orientation
UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
CGRect frame = self.tableView.frame;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.3f];
// Reduce size of the Table view
if (orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown)
frame.size.height += keyboardBounds.size.height;
else
frame.size.height += keyboardBounds.size.width;
// Apply new size of table view
self.tableView.frame = frame;
[UIView commitAnimations];
}
isKeyboardVisible = NO;
}

Answer 1

I believe most of the UITableView's automatic scrolling code resides in the UITableViewController. For example, if you have a UITextField in one of the table rows that is towards the bottom of the screen, the table automatically scrolls upwards to make way for the keyboard when the user taps on the UITextField. As you want to minimize auto-scrolling, I would suggest not using the UITableViewController. Instead, just subclass UIViewController & make it implement UITableViewDelegate & UITableViewDataSource. That being said, you would also miss out on some of the good things that UITableViewController provides.
HTH,
Akshay

Answer 2

Is bodyTextView the text view that you are trying to scroll/not scroll? If so, are you setting it's delegate somewhere else in your code? Meaning, do you have something like bodyTextView.delegate = self; somewhere? If you haven't set its delegate, that may be while it's not responding to some of your code. To be able to do this, subscribe to the text view delegate by adding <UITextViewDelegate> to your header file, along with setting its delegate as I explained.