A category or extension for UIButton to set solid background color as background image.
Add this to your Podfile
pod 'UIButton+BackgroundColor'
Import <UIButton+BackgroundColor.h>, then you can set background color with state for your UIButton using:
[self.blueButton setBackgroundColor:[UIColor blueColor] forState:UIControlStateNormal];You can also set background color default appearance for UIButton
[[UIButton appearance] setBackgroundColor:[UIColor blueColor] forState:UIControlStateNormal];