Fixes and changes.

Author: ajsecord

components/Buttons/Buttons/ViewController.m

@@ -24,7 +24,6 @@ - (void)viewDidLoad {
   [super viewDidLoad];
   self.view.backgroundColor = [UIColor whiteColor];
 
-  // Load your Material Component here.
   MDCRaisedButton *raisedButton = [MDCRaisedButton new];
   [raisedButton setTitle:@"Raised Button" forState:UIControlStateNormal];
   [raisedButton sizeToFit];
@@ -82,7 +81,7 @@ - (void)viewDidLoad {
 }
 
 - (void)didTap:(id)sender {
-  NSLog(@"Did tap %@!", NSStringFromClass([sender class]));
+  NSLog(@"%@ was tapped.", NSStringFromClass([sender class]));
 }
 
 @end

components/Buttons/ButtonsTests/ButtonsTests.m

@@ -161,7 +161,7 @@ - (void)testCurrentBackgroundColor {
 
     // Then
     XCTAssertEqual(button.state, controlState);
-    XCTAssertEqualObjects(button.currentBackgroundColor, color);
+    XCTAssertEqualObjects([button backgroundColorForState:button.state], color);
   }
 }
 
@@ -179,7 +179,7 @@ - (void)testCurrentBackgroundColorFallbackToNormal {
 
   // Then
   XCTAssertEqual(button.state, controlState);
-  XCTAssertEqualObjects(button.currentBackgroundColor, color);
+  XCTAssertEqualObjects([button backgroundColorForState:button.state], color);
 }
 
 - (void)testInkColors {
@@ -204,7 +204,7 @@ - (void)testDefaultColors {
   // Colors chosen from: https://www.google.com/design/spec/style/color.html#color-color-palette
   UIColor *blue500 = MDCColorFromRGB(0x2196F3);
   UIColor *blue300 = MDCColorFromRGB(0x64B5F6);
-  XCTAssertEqualObjects([button currentBackgroundColor], blue500);
+  XCTAssertEqualObjects([button backgroundColorForState:button.state], blue500);
   UIColor *lightBlueInk = [blue300 colorWithAlphaComponent:0.25f];
   XCTAssertEqualObjects(button.inkColor, lightBlueInk);
 }

components/Buttons/src/MDCButton.h

@@ -17,38 +17,42 @@
 #import <CoreGraphics/CoreGraphics.h>
 #import <UIKit/UIKit.h>
 
-@interface MDCButton : UIButton
-
 /**
- * The background color given this UIControl's @c state.
- * @c setBackgroundColorForState: to set the valid background colors for a given state.
+ A Material flat, raised or floating button.
+ 
+ All buttons display animated ink splashes when the user interacts with the button.
+ 
+ The title color of the button set to have an accessible contrast ratio with the button's
+ background color. To ensure this works for flat buttons (with transparent background), the caller
+ is responsible for setting (and updating, if necessary) the button's underlyingColor property.
+ 
+ All buttons set the exclusiveTouch property to YES by default, which prevents users from
+ simultaneously interacting with a button and other UI elements.
+ 
+ @see http://www.google.com/design/spec/components/buttons.html#buttons-main-buttons
  */
-@property(nullable, nonatomic, readonly, strong) UIColor *currentBackgroundColor;
+@interface MDCButton : UIButton
 
 /**
- * A color used as the button's @c backgroundColor.
- * If left unset or reset to nil for a given state, then an appropriate default color is used.
+ A color used as the button's @c backgroundColor.
+ The default value is nil, which results in a transparent background color.
+
+ @param state The state.
+ @return The background color.
  */
 - (nonnull UIColor *)backgroundColorForState:(UIControlState)state;
 
 /**
- * A color used as the button's @c backgroundColor.
- *
- * @param elevation The elevation to set.
- * @param state The state to set.
+ A color used as the button's @c backgroundColor.
+
+ @param backgroundColor The background color.
+ @param state The state.
  */
 - (void)setBackgroundColor:(nullable UIColor *)backgroundColor forState:(UIControlState)state;
 
-/**
- The ink color of the button.
- If left unset or reset to nil an appropriate default color is used.
- */
+/** The ink color of the button. */
 @property(null_resettable, nonatomic, strong) UIColor *inkColor;
 
-///** Please use @c backgroundColorForState: instead. */
-//- (void)setBackgroundColor:(nullable UIColor *)backgroundColor NS_UNAVAILABLE;
-//- (nullable UIColor *)backgroundColor NS_UNAVAILABLE;
-
 /**
  * A custom title color for the non-disabled states. The default is nil, which means that the button
  * chooses its title color automatically based on |underlyingColor|, whether the button is opaque,

components/Buttons/src/MDCButton.m

@@ -41,19 +41,22 @@
 static NSString *const MDCButtonUserElevationsKey = @"MDCButtonUserElevationsKey";
 
 // MDCButtonUserZIndicesKey provides backward compatibility with old z-index shadows values.
+// TODO: Remove from MDC, it is only useful for internal clients.
 static NSString *const MDCButtonUserZIndicesKey = @"MDCButtonUserZIndicesKey";
 
 static const NSTimeInterval MDCButtonAnimationDuration = 0.2;
 
 // http://www.google.com/design/spec/components/buttons.html#buttons-main-buttons
 static const CGFloat MDCButtonDisabledAlpha = 0.1f;
+static const uint32_t MDCButtonDefaultBackgroundColor = 0x2196F3;
 
 // Checks whether the provided floating point number is exactly zero.
 static inline BOOL MDCButtonFloatIsExactlyZero(CGFloat value) {
   return (value == 0.f);
 }
 
-static inline UIColor *MDCColorFromRGB(NSInteger rgbValue) {
+// Creates a UIColor from a 24-bit RGB color encoded as an integer.
+static inline UIColor *MDCColorFromRGB(uint32_t rgbValue) {
   return [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16)) / 255.0
                          green:((float)((rgbValue & 0x00FF00) >> 8)) / 255.0
                           blue:((float)((rgbValue & 0x0000FF) >> 0)) / 255.0
@@ -134,9 +137,11 @@ - (void)commonInit {
   // Block users from activating multiple buttons simultaneously by default.
   self.exclusiveTouch = YES;
 
-  //default background colors
-  [self setBackgroundColor:MDCColorFromRGB(0x2196F3) forState:UIControlStateNormal];
-  self.inkColor = [MDCColorFromRGB(0x64B5F6) colorWithAlphaComponent:0.25f];
+  // Default background colors.
+  [self setBackgroundColor:MDCColorFromRGB(MDCButtonDefaultBackgroundColor)
+                  forState:UIControlStateNormal];
+
+  self.inkColor = [UIColor colorWithWhite:1 alpha:CGColorGetAlpha(self.inkView.inkColor.CGColor)];
 }
 
 - (void)dealloc {
@@ -455,6 +460,8 @@ - (CGFloat)elevationForState:(UIControlState)state {
   }
   if (state & UIControlStateSelected) {
     CGFloat elevationForNormal = [self elevationForState:UIControlStateNormal];
+    // TODO(ajsecord): Why is this using the raised button values for all buttons?
+    // This should just be a factor of 2, I believe.
     if (MDCButtonFloatIsExactlyZero(elevationForNormal)) {
       return MDCShadowElevationRaisedButtonPressed;
     } else {
@@ -482,8 +489,11 @@ - (void)setElevation:(CGFloat)elevation forState:(UIControlState)state {
 
 - (void)resetElevationForState:(UIControlState)state {
   [_userElevations removeObjectForKey:@(state)];
+  [self shadowLayer].elevation = [self elevationForState:self.state];
 }
 
+#pragma mark - Private methods
+
 - (UIColor *)currentBackgroundColor {
   UIColor *color = _backgroundColors[@(self.state)];
   if (color) {
@@ -492,8 +502,6 @@ - (UIColor *)currentBackgroundColor {
   return [self backgroundColorForState:UIControlStateNormal];
 }
 
-#pragma mark - Private methods
-
 /**
  * The background color that a user would see for this button. If self.backgroundColor is not
  * transparent, then returns that. Otherwise, returns self.underlyingColor.

components/Buttons/src/MDCFlatButton.m

@@ -31,6 +31,7 @@ - (instancetype)initWithFrame:(CGRect)frame {
   if (self) {
     self.shouldRaiseOnTouch = NO;
     self.backgroundColor = nil;
+    self.inkColor = [UIColor colorWithWhite:0 alpha:CGColorGetAlpha(self.inkColor.CGColor)];
   }
   return self;
 }