Change ScrollView height based on content of the View - ios

Question

I parse some Json Data and I show it using various UITextView, for now I used a ScrollView created via Storyboard that has a height of 1000px but sometimes I can't show the whole data since it's too long to fit the ScrollView, how can I update it programmatically in order to have a height based on the content the view has to show?

Answer 1

You may calculate the height of text:
CGRect textRect = [#"your text" boundingRectWithSize:CGSizeMake(yourScrollView.width, CGFLOAT_MAX)
options:(NSStringDrawingUsesLineFragmentOrigin)
attributes:#{NSFontAttributeName:[UIFont fontWithName:#"HelveticaNeue" size:18]}
context:nil];
And then update scrollView contentSize
[yourScrollView setContentSize:CGSizeMake(yourScrollView.frame.size.width,textRect.size.height)];

Answer 2

Go to your storyboard and remove all height constraint of your UITextViews. In order to avoid warnings in the storyboard, select Intrinsic Size -> Place Holder for each UITextView in your ScrollView. The option is located in the Size Inspector (right pane). This will tell XCode know that you don't want to specify a height, you rather want them to be based on its intrinsicContentSize.
Finally, create a new class 'FitContentTextView' that inherits from UITextView. In the storyboard make all your UITextView's that you want to have enough size to fit content of type FitContentTextView
- (void)setText:(NSString *)text {
[self setScrollEnabled:YES];
[super setText:text];
[self invalidateIntrinsicContentSize];
}
- (CGSize)intrinsicContentSize {
CGSize size = [self contentSize];
return size;
}
The setScrollEnabled thing in setText is important. The method contentSize only returns enough size to fit all text if srolling is enabled. Otherwise, will return the the TextView's bounds.
Also, calling invalidateIntrinsicContentSize every time we set the text makes sure autolayout will call the method intrinsicContentSize before drawing the TextView, and add this methods to it.
Lastly, remember to pin all ScrollView's subviews vertically to its superview from top to bottom. This is the only way AutoLayout can update the contentSize of the SrollView to fit all subviews.