components/private/KeyboardWatcher/src/MDCKeyboardWatcher.h

/*
 Copyright 2016-present the Material Components for iOS authors. All Rights Reserved.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

// These notifications mirror their UIKeyboard* counterparts. They are posted after the keyboard
// watcher has updated its own internal state, so listeners are safe to query the keyboard watcher
// for its values.
OBJC_EXTERN NSString *const MDCKeyboardWatcherKeyboardWillShowNotification;
OBJC_EXTERN NSString *const MDCKeyboardWatcherKeyboardWillHideNotification;
OBJC_EXTERN NSString *const MDCKeyboardWatcherKeyboardWillChangeFrameNotification;

/**
 An object which will watch the state of the keyboard.

 The keyboard watcher calculates an offset representing the distance from the top of the keyboard to
 the bottom of the screen.
 */
@interface MDCKeyboardWatcher : NSObject

/**
 Shared singleton instance of MDCKeyboardWatcher.
 */
+ (instancetype)sharedKeyboardWatcher;

/** Extract the animation duration from the keyboard notification */
+ (NSTimeInterval)animationDurationFromKeyboardNotification:(NSNotification *)notification;

/** Extract the animation curve option from the keyboard notification */
+ (UIViewAnimationOptions)animationCurveOptionFromKeyboardNotification:
        (NSNotification *)notification;

/**
 The height of the visible keyboard view.

 Zero if the keyboard is not currently showing or is not docked.
 */
@property(nonatomic, readonly) CGFloat visibleKeyboardHeight;

#pragma mark deprecated

/**
 The distance from the top of the keyboard to the bottom of the screen.

 Zero if the keyboard is not currently showing or is not docked.
 */
@property(nonatomic, readonly) CGFloat keyboardOffset __deprecated_msg("Use visibleKeyboardHeight instead of keyboardOffset")
;

@end