Fabric: Add Fabric-compatible Slider component to iOS (ObjC code)

Summary: Objective-C side of the Fabric-compatible slider component for iOS.

Reviewed By: mdvacca

Differential Revision: D13745263

fbshipit-source-id: 647631d6fc86f81a5d4f735c507636ed9c468093

React/Fabric/Mounting/ComponentViews/Slider/RCTSliderComponentView.h

@@ -0,0 +1,21 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import <React/RCTViewComponentView.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * UIView class for root <Slider> component.
+ */
+@interface RCTSliderComponentView : RCTViewComponentView
+
+@end
+
+NS_ASSUME_NONNULL_END

React/Fabric/Mounting/ComponentViews/Slider/RCTSliderComponentView.mm

@@ -0,0 +1,92 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import "RCTSliderComponentView.h"
+
+#import <react/components/slider/SliderEventEmitter.h>
+#import <react/components/slider/SliderProps.h>
+#import <react/components/slider/SliderShadowNode.h>
+
+using namespace facebook::react;
+
+@implementation RCTSliderComponentView {
+  UISlider *_sliderView;
+  float _prevValue;
+}
+
+- (instancetype)initWithFrame:(CGRect)frame
+{
+  if (self = [super initWithFrame:frame]) {
+    static const auto defaultProps = std::make_shared<const SliderProps>();
+    _props = defaultProps;
+
+    _sliderView = [[UISlider alloc] initWithFrame:self.bounds];
+
+    [_sliderView addTarget:self
+                    action:@selector(onChange:)
+          forControlEvents:UIControlEventValueChanged];
+
+    _sliderView.value = defaultProps->value;
+
+    self.contentView = _sliderView;
+  }
+
+  return self;
+}
+
+#pragma mark - RCTComponentViewProtocol
+
++ (ComponentHandle)componentHandle
+{
+  return SliderShadowNode::Handle();
+}
+
+- (void)updateProps:(SharedProps)props oldProps:(SharedProps)oldProps
+{
+  const auto &oldSliderProps = *std::static_pointer_cast<const SliderProps>(oldProps ?: _props);
+  const auto &newSliderProps = *std::static_pointer_cast<const SliderProps>(props);
+
+  [super updateProps:props oldProps:oldProps];
+
+  // `value`
+  if (oldSliderProps.value != newSliderProps.value) {
+    _sliderView.value = newSliderProps.value;
+    _prevValue = newSliderProps.value;
+  }
+
+  // `disabled`
+  if (oldSliderProps.disabled != newSliderProps.disabled) {
+    _sliderView.enabled = !newSliderProps.disabled;
+  }
+
+  // `thumbTintColor`
+  if (oldSliderProps.thumbTintColor != newSliderProps.thumbTintColor) {
+    _sliderView.thumbTintColor = [UIColor colorWithCGColor:newSliderProps.thumbTintColor.get()];
+  }
+
+  // `minimumTrackTintColor`
+  if (oldSliderProps.minimumTrackTintColor != newSliderProps.minimumTrackTintColor) {
+    _sliderView.minimumTrackTintColor = [UIColor colorWithCGColor:newSliderProps.minimumTrackTintColor.get()];
+  }
+
+  // `maximumTrackTintColor`
+  if (oldSliderProps.maximumTrackTintColor != newSliderProps.maximumTrackTintColor) {
+    _sliderView.maximumTrackTintColor = [UIColor colorWithCGColor:newSliderProps.maximumTrackTintColor.get()];
+  }
+}
+
+- (void)onChange:(UISlider *)sender
+{
+  if (_prevValue == sender.value) {
+    return;
+  }
+  _prevValue = sender.value;
+
+  std::dynamic_pointer_cast<const SliderEventEmitter>(_eventEmitter)->onValueChange(sender.value);
+}
+
+@end

React/Fabric/Mounting/RCTComponentViewFactory.mm

@@ -16,6 +16,7 @@
 #import "RCTParagraphComponentView.h"
 #import "RCTRootComponentView.h"
 #import "RCTActivityIndicatorViewComponentView.h"
+#import "RCTSliderComponentView.h"
 #import "RCTSwitchComponentView.h"
 
 using namespace facebook::react;
@@ -37,6 +38,7 @@ + (RCTComponentViewFactory *)standardComponentViewFactory
   [componentViewFactory registerComponentViewClass:[RCTImageComponentView class]];
   [componentViewFactory registerComponentViewClass:[RCTParagraphComponentView class]];
   [componentViewFactory registerComponentViewClass:[RCTActivityIndicatorViewComponentView class]];
+  [componentViewFactory registerComponentViewClass:[RCTSliderComponentView class]];
   [componentViewFactory registerComponentViewClass:[RCTSwitchComponentView class]];
 
   return componentViewFactory;