[Slider] Add appearance properties and enable UIAppearance. (#2796)

* Add Slider appearance properties and enable UIAppearance.

Adds `thumbRadius` and `thumbElevation` as UIAppearance properties.

Makes `color`, `disabledColor`, and `trackBackgroundColor` UIAppearance-compatible.

* Added unit tests for slider.

* Remove infeasible coding unit test for now.

* Line-length formatting.

* Rename and condense color tests, sort by order that they appear in the header.

* Rename tests and mark the thumb section.

* Replace `_thumbTrack.thumbRadius` usage with `self.thumbRadius`.

* Remove NSCoding-related helper, moved to another branch.

* Search-and-replace mixup.

* Line-length fixups.

MaterialComponents.podspec

@@ -472,6 +472,7 @@ Pod::Spec.new do |mdc|
     component.source_files = "components/#{component.base_name}/src/*.{h,m}", "components/#{component.base_name}/src/private/*.{h,m}"
 
     component.dependency "MaterialComponents/Palettes"
+    component.dependency "MaterialComponents/ShadowElevations"
     component.dependency "MaterialComponents/private/ThumbTrack"
   end
 

components/Slider/src/MDCSlider.h

@@ -17,6 +17,8 @@
 #import <UIKit/UIKit.h>
 #import <CoreGraphics/CoreGraphics.h>
 
+#import "MaterialShadowElevations.h"
+
 @protocol MDCSliderDelegate;
 
 /**
@@ -31,7 +33,7 @@
      set the right and left track images (if you wanted a custom track)
      set the right (background track) color
    Same features
-     set color for thumb via @c thumbColor
+     set color for thumb via @c color
      set color of track via @c trackColor
    New features
      making the slider a snap to discrete values via @c numberOfDiscreteValues.
@@ -47,22 +49,35 @@ IB_DESIGNABLE
 
  Default color is blue.
  */
-@property(nonatomic, strong, null_resettable) UIColor *color;
+@property(nonatomic, strong, null_resettable) UIColor *color UI_APPEARANCE_SELECTOR;
 
 /**
  The color of the cursor (thumb) and track while the slider is disabled.
 
  Default color is gray.
  */
-@property(nonatomic, strong, null_resettable) UIColor *disabledColor;
+@property(nonatomic, strong, null_resettable) UIColor *disabledColor UI_APPEARANCE_SELECTOR;
 
-/*
+/**
  The color of the unfilled track that the cursor moves along (right side).
 
  Default color is gray.
  */
-@property(nonatomic, strong, null_resettable) UIColor *trackBackgroundColor;
+@property(nonatomic, strong, null_resettable) UIColor *trackBackgroundColor UI_APPEARANCE_SELECTOR;
+
+/**
+ The radius of the cursor (thumb).
+
+ Default value is 6 points.
+ */
+@property(nonatomic, assign) CGFloat thumbRadius UI_APPEARANCE_SELECTOR;
 
+/**
+ The elevation of the cursor (thumb).
+
+ Default value is MDCElevationNone.
+ */
+@property(nonatomic, assign) MDCShadowElevation thumbElevation UI_APPEARANCE_SELECTOR;
 /**
  The number of discrete values that the slider can take.
 

components/Slider/src/MDCSlider.m

@@ -23,7 +23,7 @@
 static const CGFloat kSliderDefaultWidth = 100.0f;
 static const CGFloat kSliderFrameHeight = 27.0f;
 static const CGFloat kSliderMinTouchSize = 48.0f;
-static const CGFloat kSliderThumbRadius = 6.0f;
+static const CGFloat kSliderDefaultThumbRadius = 6.0f;
 static const CGFloat kSliderAccessibilityIncrement = 0.1f;  // Matches UISlider's percent increment.
 static const CGFloat kSliderLightThemeTrackAlpha = 0.26f;
 
@@ -59,7 +59,7 @@ - (void)commonMDCSliderInit {
   _thumbTrack.delegate = self;
   _thumbTrack.disabledTrackHasThumbGaps = YES;
   _thumbTrack.trackEndsAreInset = YES;
-  _thumbTrack.thumbRadius = kSliderThumbRadius;
+  _thumbTrack.thumbRadius = kSliderDefaultThumbRadius;
   _thumbTrack.thumbIsSmallerWhenDisabled = YES;
   _thumbTrack.thumbIsHollowAtStart = YES;
   _thumbTrack.thumbGrowsWhenDragging = YES;
@@ -117,6 +117,22 @@ - (UIColor *)color {
   return _thumbTrack.primaryColor;
 }
 
+- (void)setThumbRadius:(CGFloat)thumbRadius {
+  _thumbTrack.thumbRadius = thumbRadius;
+}
+
+- (CGFloat)thumbRadius {
+  return _thumbTrack.thumbRadius;
+}
+
+- (void)setThumbElevation:(MDCShadowElevation)thumbElevation {
+  _thumbTrack.thumbElevation = thumbElevation;
+}
+
+- (MDCShadowElevation)thumbElevation {
+  return _thumbTrack.thumbElevation;
+}
+
 - (NSUInteger)numberOfDiscreteValues {
   return _thumbTrack.numDiscreteValues;
 }
@@ -227,7 +243,7 @@ - (CGSize)intrinsicContentSize {
 }
 
 - (BOOL)pointInside:(CGPoint)point withEvent:(__unused UIEvent *)event {
-  CGFloat dx = MIN(0, kSliderThumbRadius - kSliderMinTouchSize / 2);
+  CGFloat dx = MIN(0, self.thumbRadius - kSliderMinTouchSize / 2);
   CGFloat dy = MIN(0, (self.bounds.size.height - kSliderMinTouchSize) / 2);
   CGRect rect = CGRectInset(self.bounds, dx, dy);
   return CGRectContainsPoint(rect, point);