How do I size a UITextView to its content?

Question

Is there a good way to adjust the size of a UITextView to conform to its content? Say for instance I have a UITextView that contains one line of text:

"Hello world"

I then add another line of text:

"Goodbye world"

Is there a good way in Cocoa Touch to get the rect that will hold all of the lines in the text view so that I can adjust the parent view accordingly?

As another example, look at the notes' field for events in the Calendar application - note how the cell (and the UITextView it contains) expands to hold all lines of text in the notes' string.

Answer 1

To make a dynamically sizing UITextView inside a UITableViewCell, I found the following combination works in Xcode 6 with the iOS 8 SDK:

• Add a UITextView to a UITableViewCell and constrain it to the sides
• Set the UITextView's scrollEnabled property to NO. With scrolling enabled, the frame of the UITextView is independent of its content size, but with scrolling disabled, there is a relationship between the two.

• If your table is using the original default row height of 44 then it will automatically calculate row heights, but if you changed the default row height to something else, you may need to manually switch on auto-calculation of row heights in viewDidLoad:

  tableView.estimatedRowHeight = 150;
  tableView.rowHeight = UITableViewAutomaticDimension;
  

For read-only dynamically sizing UITextViews, that’s it. If you’re allowing users to edit the text in your UITextView, you also need to:

• Implement the textViewDidChange: method of the UITextViewDelegate protocol, and tell the tableView to repaint itself every time the text is edited:

  - (void)textViewDidChange:(UITextView *)textView;
  {
      [tableView beginUpdates];
      [tableView endUpdates];
  }
  

• And don’t forget to set the UITextView delegate somewhere, either in Storyboard or in tableView:cellForRowAtIndexPath:

Answer 2

Swift answer: The following code computes the height of your textView.

                let maximumLabelSize = CGSize(width: Double(textView.frame.size.width-100.0), height: DBL_MAX)
                let options = NSStringDrawingOptions.TruncatesLastVisibleLine | NSStringDrawingOptions.UsesLineFragmentOrigin
                let attribute = [NSFontAttributeName: textView.font!]
                let str = NSString(string: message)
                let labelBounds = str.boundingRectWithSize(maximumLabelSize,
                    options: NSStringDrawingOptions.UsesLineFragmentOrigin,
                    attributes: attribute,
                    context: nil)
                let myTextHeight = CGFloat(ceilf(Float(labelBounds.height)))

Now you can set the height of your textView to myTextHeight

Answer 3

The following things are enough:

1. Just remember to set scrolling enabled to NO for your UITextView:

2. Properly set Auto Layout Constraints.

You may even use UITableViewAutomaticDimension.

Answer 4

In my (limited) experience,

- (CGSize)sizeWithFont:(UIFont *)font forWidth:(CGFloat)width lineBreakMode:(UILineBreakMode)lineBreakMode

does not respect newline characters, so you can end up with a lot shorter CGSize than is actually required.

- (CGSize)sizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size

does seem to respect the newlines.

Also, the text isn't actually rendered at the top of the UITextView. In my code, I set the new height of the UITextView to be 24 pixels larger than the height returned by the sizeOfFont methods.

Answer 5

In iOS6, you can check the contentSize property of UITextView right after you set the text. In iOS7, this will no longer work. If you want to restore this behavior for iOS7, place the following code in a subclass of UITextView.

- (void)setText:(NSString *)text
{
    [super setText:text];

    if (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_6_1) {
        CGRect rect = [self.textContainer.layoutManager usedRectForTextContainer:self.textContainer];
        UIEdgeInsets inset = self.textContainerInset;
        self.contentSize = UIEdgeInsetsInsetRect(rect, inset).size;
    }
}

Answer 6

I will post right solution at the bottom of the page in case someone is brave (or despaired enough) to read to this point.

Here is gitHub repo for those, who don't want to read all that text: resizableTextView

This works with iOs7 (and I do believe it will work with iOs8) and with autolayout. You don't need magic numbers, disable layout and stuff like that. Short and elegant solution.

I think, that all constraint-related code should go to updateConstraints method. So, let's make our own ResizableTextView.

The first problem we meet here is that don't know real content size before viewDidLoad method. We can take long and buggy road and calculate it based on font size, line breaks, etc. But we need robust solution, so we'll do:

CGSize contentSize = [self sizeThatFits:CGSizeMake(self.frame.size.width, FLT_MAX)];

So now we know real contentSize no matter where we are: before or after viewDidLoad. Now add height constraint on textView (via storyboard or code, no matter how). We'll adjust that value with our contentSize.height:

[self.constraints enumerateObjectsUsingBlock:^(NSLayoutConstraint *constraint, NSUInteger idx, BOOL *stop) {
    if (constraint.firstAttribute == NSLayoutAttributeHeight) {
        constraint.constant = contentSize.height;
        *stop = YES;
    }
}];

The last thing to do is to tell superclass to updateConstraints.

[super updateConstraints];

Now our class looks like:

ResizableTextView.m

- (void) updateConstraints {
    CGSize contentSize = [self sizeThatFits:CGSizeMake(self.frame.size.width, FLT_MAX)];

    [self.constraints enumerateObjectsUsingBlock:^(NSLayoutConstraint *constraint, NSUInteger idx, BOOL *stop) {
        if (constraint.firstAttribute == NSLayoutAttributeHeight) {
            constraint.constant = contentSize.height;
            *stop = YES;
        }
    }];

    [super updateConstraints];
}

Pretty and clean, right? And you don't have to deal with that code in your controllers!

But wait! Y NO ANIMATION!

You can easily animate changes to make textView stretch smoothly. Here is an example:

    [self.view layoutIfNeeded];
    // do your own text change here.
    self.infoTextView.text = [NSString stringWithFormat:@"%@, %@", self.infoTextView.text, self.infoTextView.text];
    [self.infoTextView setNeedsUpdateConstraints];
    [self.infoTextView updateConstraintsIfNeeded];
    [UIView animateWithDuration:1 delay:0 options:UIViewAnimationOptionLayoutSubviews animations:^{
        [self.view layoutIfNeeded];
    } completion:nil];