//
//  UIDynamicAnimator.h
//  UIKit
//
//  Copyright (c) 2012-2015 Apple Inc. All rights reserved.
//

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

NS_ASSUME_NONNULL_BEGIN

@class UIDynamicBehavior;   // 動態(tài)行為
@class UIDynamicAnimator;   // 動態(tài)動畫管理者


// 動畫管理者的代理協(xié)議
@protocol UIDynamicAnimatorDelegate <NSObject>

@optional

// 動畫將要啟動
- (void)dynamicAnimatorWillResume:(UIDynamicAnimator *)animator;

// 動畫已經(jīng)暫停
- (void)dynamicAnimatorDidPause:(UIDynamicAnimator *)animator;

@end

// 動畫管理者
NS_CLASS_AVAILABLE_IOS(7_0) @interface UIDynamicAnimator: NSObject

// When you initialize a dynamic animator with this method, you should only associates views with your behaviors.
// the behaviors (and their dynamic items) that you add to the animator employ the reference view’s coordinate system.
// 通過傳遞引用視圖的方式來創(chuàng)建動畫管理者
// 引用視圖只是給動畫執(zhí)行者提供坐標(biāo)體系
- (instancetype)initWithReferenceView:(UIView *)view NS_DESIGNATED_INITIALIZER;

// 添加動畫行為
- (void)addBehavior:(UIDynamicBehavior *)behavior;
// 移除動畫行為
- (void)removeBehavior:(UIDynamicBehavior *)behavior;
// 移除所有動畫行為
- (void)removeAllBehaviors;


// 動畫執(zhí)行者引用的 View 
@property (nullable, nonatomic, readonly) UIView *referenceView;

// 獲取所有的動畫行為
@property (nonatomic, readonly, copy) NSArray<__kindof UIDynamicBehavior*> *behaviors;

// Returns the dynamic items associated with the animator’s behaviors that intersect a specified rectangle
// 獲取某個范圍內(nèi)的 item 
- (NSArray<id<UIDynamicItem>> *)itemsInRect:(CGRect)rect;

// Update the item state in the animator if an external change was made to this item 
// 更新項目狀態(tài)的動畫師如果外部改變了這個項目
- (void)updateItemUsingCurrentState:(id <UIDynamicItem>)item;

// 是否正在運(yùn)行
@property (nonatomic, readonly, getter = isRunning) BOOL running;

// 獲取已經(jīng)執(zhí)行的時間
#if UIKIT_DEFINE_AS_PROPERTIES
@property (nonatomic, readonly) NSTimeInterval elapsedTime;
#else
// elapsed : 過去的，已經(jīng)消失的躁垛。
- (NSTimeInterval)elapsedTime;
#endif

// 動畫管理者代理
@property (nullable, nonatomic, weak) id <UIDynamicAnimatorDelegate> delegate;

@end






// collectionView 附加的方法
@interface UIDynamicAnimator (UICollectionViewAdditions)

// When you initialize a dynamic animator with this method, you should only associate collection view layout attributes with your behaviors.
// The animator will employ thecollection view layout’s content size coordinate system.
// 通過傳遞布局對象的方式來創(chuàng)建動畫管理對象
// 主要是用來提供一個坐標(biāo)體系
- (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout *)layout;

// The three convenience methods returning layout attributes (if associated to behaviors in the animator) if the animator was configured with collection view layout
- (nullable UICollectionViewLayoutAttributes *)layoutAttributesForCellAtIndexPath:(NSIndexPath *)indexPath;
- (nullable UICollectionViewLayoutAttributes *)layoutAttributesForSupplementaryViewOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath;
- (nullable UICollectionViewLayoutAttributes *)layoutAttributesForDecorationViewOfKind:(NSString *)decorationViewKind atIndexPath:(NSIndexPath *)indexPath;

@end

NS_ASSUME_NONNULL_END