react-native/React/Modules/RCTKeyboardObserver.m

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#import "RCTKeyboardObserver.h"

#import "RCTEventDispatcher.h"

static NSDictionary *RCTParseKeyboardNotification(NSNotification *notification);

@implementation RCTKeyboardObserver

RCT_EXPORT_MODULE()

- (void)startObserving
{
#if !TARGET_OS_TV

  NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];

#define ADD_KEYBOARD_HANDLER(NAME, SELECTOR) \
  [nc addObserver:self selector:@selector(SELECTOR:) name:NAME object:nil]

  ADD_KEYBOARD_HANDLER(UIKeyboardWillShowNotification, keyboardWillShow);
  ADD_KEYBOARD_HANDLER(UIKeyboardDidShowNotification, keyboardDidShow);
  ADD_KEYBOARD_HANDLER(UIKeyboardWillHideNotification, keyboardWillHide);
  ADD_KEYBOARD_HANDLER(UIKeyboardDidHideNotification, keyboardDidHide);
  ADD_KEYBOARD_HANDLER(UIKeyboardWillChangeFrameNotification, keyboardWillChangeFrame);
  ADD_KEYBOARD_HANDLER(UIKeyboardDidChangeFrameNotification, keyboardDidChangeFrame);

#undef ADD_KEYBOARD_HANDLER

#endif

}

- (NSArray<NSString *> *)supportedEvents
{
  return @[@"keyboardWillShow",
           @"keyboardDidShow",
           @"keyboardWillHide",
           @"keyboardDidHide",
           @"keyboardWillChangeFrame",
           @"keyboardDidChangeFrame"];
}

- (void)stopObserving
{
  [[NSNotificationCenter defaultCenter] removeObserver:self];
}

// Bridge might be already invalidated by the time the keyboard is about to be dismissed.
// This might happen, for example, when reload from the packager is performed.
// Thus we need to check against nil here.
#define IMPLEMENT_KEYBOARD_HANDLER(EVENT) \
- (void)EVENT:(NSNotification *)notification \
{ \
  if (!self.bridge) { \
    return; \
  } \
  [self sendEventWithName:@#EVENT \
    body:RCTParseKeyboardNotification(notification)]; \
}

IMPLEMENT_KEYBOARD_HANDLER(keyboardWillShow)
IMPLEMENT_KEYBOARD_HANDLER(keyboardDidShow)
IMPLEMENT_KEYBOARD_HANDLER(keyboardWillHide)
IMPLEMENT_KEYBOARD_HANDLER(keyboardDidHide)
IMPLEMENT_KEYBOARD_HANDLER(keyboardWillChangeFrame)
IMPLEMENT_KEYBOARD_HANDLER(keyboardDidChangeFrame)

@end

NS_INLINE NSDictionary *RCTRectDictionaryValue(CGRect rect)
{
  return @{
    @"screenX": @(rect.origin.x),
    @"screenY": @(rect.origin.y),
    @"width": @(rect.size.width),
    @"height": @(rect.size.height),
  };
}

static NSString *RCTAnimationNameForCurve(UIViewAnimationCurve curve)
{
  switch (curve) {
    case UIViewAnimationCurveEaseIn:
      return @"easeIn";
    case UIViewAnimationCurveEaseInOut:
      return @"easeInEaseOut";
    case UIViewAnimationCurveEaseOut:
      return @"easeOut";
    case UIViewAnimationCurveLinear:
      return @"linear";
    default:
      return @"keyboard";
  }
}

static NSDictionary *RCTParseKeyboardNotification(NSNotification *notification)
{
#if TARGET_OS_TV
  return @{};
#else
  NSDictionary *userInfo = notification.userInfo;
  CGRect beginFrame = [userInfo[UIKeyboardFrameBeginUserInfoKey] CGRectValue];
  CGRect endFrame = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
  NSTimeInterval duration = [userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
  UIViewAnimationCurve curve = [userInfo[UIKeyboardAnimationCurveUserInfoKey] integerValue];

  return @{
    @"startCoordinates": RCTRectDictionaryValue(beginFrame),
    @"endCoordinates": RCTRectDictionaryValue(endFrame),
    @"duration": @(duration * 1000.0), // ms
    @"easing": RCTAnimationNameForCurve(curve),
  };
#endif
}