談?wù)刬OS中的動(dòng)力學(xué)?。。?！

UIDynamic物理仿真 下面介紹一下各種屬性

一、簡(jiǎn)單介紹

1.什么是UIDynamic

UIDynamic是從iOS 7開(kāi)始引入的一種新技術(shù)，隸屬于UIKit框架,可以認(rèn)為是一種物理引擎，能模擬和仿真現(xiàn)實(shí)生活中的物理現(xiàn)象
如：重力、彈性碰撞等現(xiàn)象

2.物理引擎的價(jià)值

廣泛用于游戲開(kāi)發(fā)，經(jīng)典成功案例是“憤怒的小鳥(niǎo)”
讓開(kāi)發(fā)人員可以在遠(yuǎn)離物理學(xué)公式的情況下，實(shí)現(xiàn)炫酷的物理仿真效果
提高了游戲開(kāi)發(fā)效率，產(chǎn)生更多優(yōu)秀好玩的物理仿真游戲

3.知名的2D物理引擎

Box2d
Chipmunk

二、使用步驟

要想使用UIDynamic來(lái)實(shí)現(xiàn)物理仿真效果，大致的步驟如下

（1）創(chuàng)建一個(gè)物理仿真器（順便設(shè)置仿真范圍）
（2）創(chuàng)建相應(yīng)的物理仿真行為（順便添加物理仿真元素）
（3）將物理仿真行為添加到物理仿真器中 ? 開(kāi)始仿真

三、相關(guān)說(shuō)明

1.三個(gè)概念
（1）誰(shuí)要進(jìn)行物理仿真？
　　物理仿真元素（Dynamic Item）
 
（2）執(zhí)行怎樣的物理仿真效果？怎樣的動(dòng)畫(huà)效果？
　　物理仿真行為（Dynamic Behavior） 
 
（3）讓物理仿真元素執(zhí)行具體的物理仿真行為
　　物理仿真器（Dynamic Animator）
2.物理仿真元素
注意：

不是任何對(duì)象都能做物理仿真元素
不是任何對(duì)象都能進(jìn)行物理仿真

物理仿真元素要素：
任何遵守了UIDynamicItem協(xié)議的對(duì)象
UIView默認(rèn)已經(jīng)遵守了UIDynamicItem協(xié)議，因此任何UI控件都能做物理仿真
UICollectionViewLayoutAttributes類默認(rèn)也遵守UIDynamicItem協(xié)議

四、物理仿真器 ------------UIDynamicAnimator

須知：它可以讓物理仿真元素執(zhí)行物理仿真行為，它是UIDynamicAnimator類型的對(duì)象

    物理仿真器屬性方法說(shuō)明

（1）UIDynamicAnimator的常見(jiàn)方法
- (instancetype)initWithReferenceView:(UIView *)view; //初始化一個(gè)仿真器。view參數(shù)：是一個(gè)參照視圖，表示物理仿真的范圍
　　- (void)addBehavior:(UIDynamicBehavior *)behavior; 　　//添加1個(gè)物理仿真行為
　　- (void)removeBehavior:(UIDynamicBehavior *)behavior;　　//移除1個(gè)物理仿真行為
　　- (void)removeAllBehaviors; 　　//移除之前添加過(guò)的所有物理仿真行為

   - (NSArray<id<UIDynamicItem>> *)itemsInRect:(CGRect)rect; 
   - (void)updateItemUsingCurrentState:(id <UIDynamicItem>)item;//(更新dynamic item在UIDynamicAnimator內(nèi)部的代表的狀態(tài))，dynamic item被加入到UIDynamicAnimator后，你更改了dynamic item的狀態(tài)，你應(yīng)該使用這個(gè)方法更新dynamic item的狀態(tài)。
   - (NSTimeInterval)elapsedTime;   //返回動(dòng)畫(huà)開(kāi)始到現(xiàn)在的時(shí)間間隔

（2）UIDynamicAnimator的常見(jiàn)屬性

　　@property (nonatomic, readonly) UIView* referenceView;  //參照視圖 
　　@property (nonatomic, readonly, copy) NSArray* behaviors;//添加到物理仿真器中的所有物理仿真行為
　　@property (nonatomic, readonly, getter = isRunning) BOOL running;//是否正在進(jìn)行物理仿真
　　@property (nonatomic, assign) id <UIDynamicAnimatorDelegate> delegate;//代理對(duì)象（能監(jiān)聽(tīng)物理仿真器的仿真過(guò)程，比如開(kāi)始和結(jié)束）{ 
        @optional
       - (void)dynamicAnimatorWillResume:(UIDynamicAnimator *)animator;
       - (void)dynamicAnimatorDidPause:(UIDynamicAnimator *)animator;
   }

（3）UIDynamicAnimator中的Collection View Additions：     
    ?    - (UICollectionViewLayoutAttributes *)layoutAttributesForCellAtIndexPath:(NSIndexPath *)indexPath；//返回指定位置collection view cell的布局屬性
    ?    - (UICollectionViewLayoutAttributes *)layoutAttributesForDecorationViewOfKind:(NSString *)decorationViewKind atIndexPath:(NSIndexPath *)indexPath； //返回indexPath位置上collection view cell的指定(用decorationViewKind指定)decorationView的布局屬性。
    ?    - (UICollectionViewLayoutAttributes *)layoutAttributesForSupplementaryViewOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath；//返回indexPath位置上collection view cell的指定(用kind指定)SupplementaryView的布局屬性。

五、物理仿真行為 ------------UIDynamicBehavior

（1）UIDynamic提供了以下幾種物理仿真行為
UIGravityBehavior：重力行為
UICollisionBehavior：碰撞行為
UISnapBehavior：捕捉行為
UIPushBehavior：推動(dòng)行為
UIAttachmentBehavior：附著行為
UIDynamicItemBehavior：動(dòng)力元素行為

（2）物理仿真行為須知

上述所有物理仿真行為都繼承自UIDynamicBehavior，所有的UIDynamicBehavior都可以獨(dú)立進(jìn)行，組合使用多種行為時(shí)，可以實(shí)現(xiàn)一些比較復(fù)雜的效果。

（3）UIDynamicBehavior屬性方法介紹

- (void)addChildBehavior:(UIDynamicBehavior *)behavior;
- (void)removeChildBehavior:(UIDynamicBehavior *)behavior;

@property (nonatomic, readonly, copy) NSArray<__kindof UIDynamicBehavior *> *childBehaviors;

@property (nullable, nonatomic,copy) void (^action)(void);

- (void)willMoveToAnimator:(nullable UIDynamicAnimator *)dynamicAnimator; 

@property (nullable, nonatomic, readonly) UIDynamicAnimator *dynamicAnimator;

UIGravityBehavior（重力）

         - (instancetype)initWithItems:(NSArray<id <UIDynamicItem>> *)items;//初始化

        - (void)addItem:(id <UIDynamicItem>)item;//添加
        - (void)removeItem:(id <UIDynamicItem>)item;//移除
        @property (nonatomic, readonly, copy) NSArray<id <UIDynamicItem>> *items;//行為數(shù)組

        @property (readwrite, nonatomic) CGVector gravityDirection;//運(yùn)動(dòng)方向，默認(rèn)是(0.0f, 1.0f)。dx為-1.0f時(shí)向左運(yùn)動(dòng)，dy為-1.0時(shí)向上運(yùn)動(dòng)，所以根據(jù)0.0~1.0可以定位所有的方向。

        @property (readwrite, nonatomic) CGFloat angle;//重力方向（是一個(gè)角度，以x軸正方向?yàn)?°，順時(shí)針正數(shù)，逆時(shí)針負(fù)數(shù)）
        @property (readwrite, nonatomic) CGFloat magnitude;/量級(jí)（用來(lái)控制加速度，1.0代表加速度是1000 points /second2）可以去負(fù)數(shù)
       - (void)setAngle:(CGFloat)angle magnitude:(CGFloat)magnitude;//

UICollisionBehavior（碰撞）

- (instancetype)initWithItems:(NSArray<id <UIDynamicItem>> *)items;//初始化

- (void)addItem:(id <UIDynamicItem>)item;//添加
- (void)removeItem:(id <UIDynamicItem>)item;//移除

@property (nonatomic, readonly, copy) NSArray<id <UIDynamicItem>> *items;//碰撞行為數(shù)組

@property (nonatomic, readwrite) UICollisionBehaviorMode collisionMode;//碰撞模式（分三種，   
        UICollisionBehaviorModeItems        = 1 << 0,元素碰撞
        UICollisionBehaviorModeBoundaries   = 1 << 1, 邊界碰撞
        UICollisionBehaviorModeEverything   = NSUIntegerMax 全體碰撞）

@property (nonatomic, readwrite) BOOL translatesReferenceBoundsIntoBoundary;//是否以參照視圖的bounds為邊界

@property (nullable, nonatomic, weak, readwrite) id <UICollisionBehaviorDelegate> collisionDelegate;//代理
{-------------------------------------代理方法
- (void)collisionBehavior:(UICollisionBehavior *)behavior beganContactForItem:(id <UIDynamicItem>)item1 withItem:(id <UIDynamicItem>)item2 atPoint:(CGPoint)p;
- (void)collisionBehavior:(UICollisionBehavior *)behavior endedContactForItem:(id <UIDynamicItem>)item1 withItem:(id <UIDynamicItem>)item2;

// The identifier of a boundary created with translatesReferenceBoundsIntoBoundary or setTranslatesReferenceBoundsIntoBoundaryWithInsets is nil
- (void)collisionBehavior:(UICollisionBehavior*)behavior beganContactForItem:(id <UIDynamicItem>)item withBoundaryIdentifier:(nullable id <NSCopying>)identifier atPoint:(CGPoint)p;
- (void)collisionBehavior:(UICollisionBehavior*)behavior endedContactForItem:(id <UIDynamicItem>)item withBoundaryIdentifier:(nullable id <NSCopying>)identifier;
}
 - (void)setTranslatesReferenceBoundsIntoBoundaryWithInsets:(UIEdgeInsets)insets;//

- (void)addBoundaryWithIdentifier:(id <NSCopying>)identifier forPath:(UIBezierPath *)bezierPath;//添加一個(gè)path作為碰撞邊界
- (void)addBoundaryWithIdentifier:(id <NSCopying>)identifier fromPoint:(CGPoint)p1 toPoint:(CGPoint)p2;//添加一條線作為碰撞邊界
- (nullable UIBezierPath *)boundaryWithIdentifier:(id <NSCopying>)identifier;//
- (void)removeBoundaryWithIdentifier:(id <NSCopying>)identifier; //移除某個(gè)的
@property (nullable, nonatomic, readonly, copy) NSArray<id <NSCopying>> *boundaryIdentifiers;//
- (void)removeAllBoundaries;//移除所有

UISnapBehavior（捕捉）

- (instancetype)initWithItem:(id <UIDynamicItem>)item snapToPoint:(CGPoint)point;//初始化

@property (nonatomic, assign) CGPoint snapPoint;
@property (nonatomic, assign) CGFloat damping;//用于減幅、減震（取值范圍是0.0 ~ 1.0，值越大，震動(dòng)幅度越?。?注意：
//2.執(zhí)行捕捉行為
43     //注意：這個(gè)控件只能用在一個(gè)仿真行為上，如果要擁有持續(xù)的仿真行為，那么需要把之前的所有仿真行為刪除
44     //刪除之前的所有仿真行為
45     [self.animator removeAllBehaviors];
46     [self.animator addBehavior:snap];

UIPushBehavior（推動(dòng)）

- (instancetype)initWithItems:(NSArray<id <UIDynamicItem>> *)items mode:(UIPushBehaviorMode)mode;
- (void)addItem:(id <UIDynamicItem>)item;
- (void)removeItem:(id <UIDynamicItem>)item;
@property (nonatomic, readonly, copy) NSArray<id <UIDynamicItem>> *items;

- (UIOffset)targetOffsetFromCenterForItem:(id <UIDynamicItem>)item;//
- (void)setTargetOffsetFromCenter:(UIOffset)o forItem:(id <UIDynamicItem>)item;//

@property (nonatomic, readonly) UIPushBehaviorMode mode;//{
    UIPushBehaviorModeContinuous,//持續(xù)的力
    UIPushBehaviorModeInstantaneous //一次性的力
}
@property (nonatomic, readwrite) BOOL active;//默認(rèn)值是YES，將其設(shè)置為NO，可以將行為停止。

@property (readwrite, nonatomic) CGFloat angle;//角度
@property (readwrite, nonatomic) CGFloat magnitude;//加速度
@property (readwrite, nonatomic) CGVector pushDirection;//運(yùn)動(dòng)方向

- (void)setAngle:(CGFloat)angle magnitude:(CGFloat)magnitude;//

UIAttachmentBehavior(附著)

- (instancetype)initWithItem:(id <UIDynamicItem>)item attachedToAnchor:(CGPoint)point;
- (instancetype)initWithItem:(id <UIDynamicItem>)item offsetFromCenter:(UIOffset)offset attachedToAnchor:(CGPoint)point;

- (instancetype)initWithItem:(id <UIDynamicItem>)item1 attachedToItem:(id <UIDynamicItem>)item2;
- (instancetype)initWithItem:(id <UIDynamicItem>)item1 offsetFromCenter:(UIOffset)offset1 attachedToItem:(id <UIDynamicItem>)item2 offsetFromCenter:(UIOffset)offset2;


+ (instancetype)slidingAttachmentWithItem:(id <UIDynamicItem>)item1 attachedToItem:(id <UIDynamicItem>)item2 attachmentAnchor:(CGPoint)point axisOfTranslation:(CGVector)axis;

+ (instancetype)slidingAttachmentWithItem:(id <UIDynamicItem>)item attachmentAnchor:(CGPoint)point axisOfTranslation:(CGVector)axis;

+ (instancetype)limitAttachmentWithItem:(id <UIDynamicItem>)item1 offsetFromCenter:(UIOffset)offset1 attachedToItem:(id <UIDynamicItem>)item2 offsetFromCenter:(UIOffset)offset2;

+ (instancetype)fixedAttachmentWithItem:(id <UIDynamicItem>)item1 attachedToItem:(id <UIDynamicItem>)item2 attachmentAnchor:(CGPoint)point;

+ (instancetype)pinAttachmentWithItem:(id <UIDynamicItem>)item1 attachedToItem:(id <UIDynamicItem>)item2 attachmentAnchor:(CGPoint)point;

@property (nonatomic, readonly, copy) NSArray<id <UIDynamicItem>> *items;

@property (readonly, nonatomic) UIAttachmentBehaviorType attachedBehaviorType;//{
    UIAttachmentBehaviorTypeItems,
    UIAttachmentBehaviorTypeAnchor 
}
@property (readwrite, nonatomic) CGPoint anchorPoint;//

@property (readwrite, nonatomic) CGFloat length; //
@property (readwrite, nonatomic) CGFloat damping; //振幅
@property (readwrite, nonatomic) CGFloat frequency; //頻率
@property (readwrite, nonatomic) CGFloat frictionTorque;//
@property (readwrite, nonatomic) UIFloatRange attachmentRange; //

UIDynamicItemBehavior：動(dòng)力元素行為

- (instancetype)initWithItems:(NSArray<id <UIDynamicItem>> *)items;//

- (void)addItem:(id <UIDynamicItem>)item;//
- (void)removeItem:(id <UIDynamicItem>)item;//
@property (nonatomic, readonly, copy) NSArray<id <UIDynamicItem>> *items;//

@property (readwrite, nonatomic) CGFloat elasticity; //（彈性系數(shù)）決定了碰撞的彈性程度，比如碰撞時(shí)物體的彈性
@property (readwrite, nonatomic) CGFloat friction;//（摩擦系數(shù)）決定了沿接觸面滑動(dòng)時(shí)的摩擦力大小
@property (readwrite, nonatomic) CGFloat density;//（密度） 跟size結(jié)合使用，計(jì)算物體的總質(zhì)量。質(zhì)量越大，物體加速或減速就越困難
@property (readwrite, nonatomic) CGFloat resistance;//（阻力）：決定線性移動(dòng)的阻力大小，與摩擦系數(shù)不同，摩擦系數(shù)只作用于滑動(dòng)運(yùn)動(dòng)
@property (readwrite, nonatomic) CGFloat angularResistance;//（角阻力） ：決定旋轉(zhuǎn)運(yùn)動(dòng)時(shí)的阻力大小

@property (readwrite, nonatomic) CGFloat charge;//

@property (nonatomic, getter = isAnchored) BOOL anchored;//

@property (readwrite, nonatomic) BOOL allowsRotation; //（允許旋轉(zhuǎn)）：這個(gè)屬性很有意思，它在真實(shí)的物理世界沒(méi)有對(duì)應(yīng)的模型。設(shè)置這個(gè)屬性為 NO 物體就完全不會(huì)轉(zhuǎn)動(dòng)，而無(wú)論施加多大的轉(zhuǎn)動(dòng)力

- (void)addLinearVelocity:(CGPoint)velocity forItem:(id <UIDynamicItem>)item;//
- (CGPoint)linearVelocityForItem:(id <UIDynamicItem>)item;//

- (void)addAngularVelocity:(CGFloat)velocity forItem:(id <UIDynamicItem>)item;//
- (CGFloat)angularVelocityForItem:(id <UIDynamicItem>)item;/
最后編輯于 ：
?著作權(quán)歸作者所有,轉(zhuǎn)載或內(nèi)容合作請(qǐng)聯(lián)系作者
【社區(qū)內(nèi)容提示】社區(qū)部分內(nèi)容疑似由AI輔助生成，瀏覽時(shí)請(qǐng)結(jié)合常識(shí)與多方信息審慎甄別。
平臺(tái)聲明：文章內(nèi)容（如有圖片或視頻亦包括在內(nèi)）由作者上傳并發(fā)布，文章內(nèi)容僅代表作者本人觀點(diǎn)，簡(jiǎn)書(shū)系信息發(fā)布平臺(tái)，僅提供信息存儲(chǔ)服務(wù)。

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容