Chinese characters interline spacing in UITextView - ios

Question

I have translated an app into Simplified Chinese.
The app is using a UITextView and the contents of it is Simplified Chinese text.
I have noticed that (sometimes not always) the interline spacing is wrong, the lines are practically touching each other :
I am setting the contents of the UITextview via an attributed string that I create based on a required pointsize like this:
-(NSMutableAttributedString*) textWithPointSize:(CGFloat)pointSize
{
UIFont * myFontDescr = [UIFont systemFontOfSize:pointSize];
NSMutableAttributedString * description = [[NSMutableAttributedString alloc] initWithString:self.exercise.descr attributes:#{NSFontAttributeName:myFontDescr}];
UIFont * myFontTips = [UIFont italicSystemFontOfSize:pointSize];
NSMutableAttributedString * tips = [[NSMutableAttributedString alloc] initWithString:self.exercise.tips attributes:#{NSFontAttributeName:myFontTips}];
NSMutableAttributedString * text = [[NSMutableAttributedString alloc] initWithAttributedString:description];
[text appendAttributedString:[[NSAttributedString alloc] initWithString:#"\n\n"]];
[text appendAttributedString:tips];
return text;
}
I am using the systemFontOfSize: function, I guess this should handle Chinese characters correctly? Any ideas why this could be happening?

Answer 1

I did not find out why but I implemented a work around by explicitly setting the interline spacing (only when language is Chinese) like this:
//for chinese language we have detected a problem with the interline spacing
//it does happen randomly, and so to workaround this we set the linespacing explicitly
if ( [NSLocalizedString(#"__CurrentLanguage",#"zh-Hans") isEqualToString:#"zh-Hans"] ) {
//make paragraph styl with interline spacing
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.lineSpacing = 0.25 * pointSize;
//font for description
UIFont * myFontDescr = [UIFont systemFontOfSize:pointSize];
NSMutableAttributedString * description = [[NSMutableAttributedString alloc] initWithString:self.exercise.descr attributes:#{NSFontAttributeName:myFontDescr, NSParagraphStyleAttributeName:paragraphStyle}];
//font for tips
UIFont * myFontTips = [UIFont italicSystemFontOfSize:pointSize];
NSMutableAttributedString * tips = [[NSMutableAttributedString alloc] initWithString:self.exercise.tips attributes:#{NSFontAttributeName:myFontTips,NSParagraphStyleAttributeName:paragraphStyle}];
//add description then...
NSMutableAttributedString * text = [[NSMutableAttributedString alloc] initWithAttributedString:description];
//concat the tips (with 2x newline in between)
[text appendAttributedString:[[NSAttributedString alloc] initWithString:#"\n\n"]];
[text appendAttributedString:tips];
//return value
return text;
}
//its not chinese, so do "normal" stuff