exposing the focused underline color

Author: louoso

MaterialTextField/MFTextField.h

@@ -60,6 +60,11 @@ IB_DESIGNABLE
  */
 @property (nonatomic) IBInspectable UIColor *underlineColor;
 
+/**
+ * The color of the underline when the text field is in focus.
+ */
+@property (nonatomic) IBInspectable UIColor *focusedUnderlineColor;
+
 /**
  * To display an error under the text field, provide an NSError with a localized description.
  *

MaterialTextField/MFTextField.m

@@ -357,7 +357,8 @@ - (void)updateUnderlineColor
         underlineColor = self.errorColor;
     }
     else {
-        underlineColor = self.isFirstResponder ? self.tintColor : self.underlineColor;
+        UIColor * focusedUnderlineColor = self.focusedUnderlineColor ?: self.tintColor;
+        underlineColor = self.isFirstResponder ? focusedUnderlineColor : self.underlineColor;
     }
 
     self.underlineLayer.backgroundColor = underlineColor.CGColor;