This is what I want to achieve:
I'm thinking about having two separate attributed strings and combine them together. Not sure if this is the only way?
UPDATE
The button displays "(null)" if using setAttributedTitle. It can display the right string with no attributes if using setTitle.
Still cannot display in the intended way. Any idea?
// Set current bar button attributes
NSMutableAttributedString *currentBarAttributedString = [[NSMutableAttributedString alloc] init];
[currentBarAttributedString appendAttributedString:[[NSAttributedString alloc] initWithString:@"REQUEST\n"
attributes:@{NSUnderlineStyleAttributeName: @(NSUnderlineStyleNone)}]];
[currentBarAttributedString appendAttributedString:[[NSAttributedString alloc] initWithString:@"EQUIPMENT"
attributes:@{NSUnderlineStyleAttributeName: @(NSUnderlineStyleSingle)}]];
// Initialize buttons and set titles
UIButton *button1 = [UIButton buttonWithType:UIButtonTypeCustom];
[button1 setAttributedTitle:currentBarAttributedString forState:UIControlStateNormal];
// [button1 setTitle:[currentBarAttributedString string] forState:UIControlStateNormal];