UITextView visually changing content position when pasting in text

Question

I have a UITextView which is designed to enlarge to fit the contentView when needed. When I paste in a paragraph of text, however, it puts the start and end points of the content vertically in the wrong places. Entering or deleting a character resets it back to the correct position.

Any ideas why this is?

-(void)textViewDidChange:(UITextView *)textView {
    self.textView.frame = CGRectMake(
        self.textView.frame.origin.x,
        self.textView.frame.origin.y,
        self.textView.frame.size.width,
        self.textView.contentSize.height + HEADER_ADDITIONAL_HEIGHT);

    self.textView.contentOffset = CGPointMake(0, 0);

    self.previousContentSize = textView.contentSize;
}

Answer 1

When I used:

textView.contentSize = textView.frame.size;  
textView.contentOffset = CGPointZero;  

It solved my issue, but created a new issue where we sometimes get weird scrolling while typing or deleting text. So, I used this:

textView.contentSize = CGSizeMake( textView.contentSize.width,
                                   textView.contentSize.height+1);  

This also solved the issue. I think what we all need here is the effect which we get whenever the contentSize of a textview is changed. Unfortunately, I do not know what this effect is. If somebody knows, please tell.

Update: I have found a method which you can use to solve your issue (I used this to resolve mine). You can ask NSLayoutMAnager to refresh the entire layout:

[textView.textStorage edited:NSTextStorageEditedCharacters range:NSMakeRange(0, textView.textStorage.length) changeInLength:0];

NSLayoutManager attempts to avoid refreshing the layout because it's time consuming and takes a lot of work, so it's set up to only do it when absolutely necessary (lazily). There are a number of invalidateLayout functions related to this class but none of them cause an actual re-layout when called.