UIDynamicAnimator - 仿真物理学

UIDynamicAnimator - 运动管理

UIDynamicBehavior - 运动行为（基类）

• UIGravityBehavior *gravity； - 重力
• UICollisionBehavior *collision; - 碰撞
• UIAttachmentBehavior *attach; - 吸附
• UISnapBehavior *snap; - 振动
• UIPushBehavior *push; - 推

基本流程

• 1 创建运动管理
• 2 创建运动行为
• 3 运动管理 添加 运动行为
• 4 使用的时候，运动行为添加 运动物体。
• 5 注意remove

分开的比较简单，复合就比较多变。

UIGravityBehavior 重力

• 1 UIDynamicAnimator 运动管理者

    // 注：运动参照物 self.testView.
    self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.testView];
    self.animator.delegate = self;
    ...

- (void)dynamicAnimatorWillResume:(UIDynamicAnimator *)animator {
    // 开始运动    
}
- (void)dynamicAnimatorDidPause:(UIDynamicAnimator *)animator {
    // 运动结束
}

• 2 UIGravityBehavior 重力行为

    self.gravity = [[UIGravityBehavior alloc] init];
    
    self.gravity.gravityDirection = CGVectorMake(0.1, 0.3);// 方向 和 速度大小 的 矢量

    self.gravity.angle = M_PI;// 方向 弧度
    self.gravity.magnitude = 1.;// 重力加速度（速度大小）1000 point/s2  举例：y=gt2

    [self.gravity setAngle:M_PI magnitude:0.8];// 动态修改
    
    [self.animator addBehavior:self.gravity];

• 3 添加 item

- (void)toucheTest {
    UIView *vvv = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 30, 30)];
    vvv.backgroundColor = [UIColor redColor];
    [self.testView addSubview:vvv];
    
    [self.gravity addItem:vvv];
}

• 4 必要的时候 remove

    NSArray *items = self.gravity.items;
   [self.gravity removeItem:vvv];// 注意必要的时候remove

UICollisionBehavior 碰撞

基本步骤与上面的一样，下面直接 运动行为。

// 一般设置
    self.collision = [[UICollisionBehavior alloc] init];
    self.collision.collisionDelegate = self;
    [self.animator addBehavior:self.collision];

// 边界设置
    self.collision.collisionMode = UICollisionBehaviorModeEverything;// 碰撞 内容
    /*
     typedef NS_OPTIONS(NSUInteger, UICollisionBehaviorMode) {
     UICollisionBehaviorModeItems        = 1 << 0,
     UICollisionBehaviorModeBoundaries   = 1 << 1,
     UICollisionBehaviorModeEverything   = NSUIntegerMax
     } NS_ENUM_AVAILABLE_IOS(7_0);
     */
    
    self.collision.translatesReferenceBoundsIntoBoundary = YES;// 使用 参考边界
    [self.collision setTranslatesReferenceBoundsIntoBoundaryWithInsets:UIEdgeInsetsMake(10, 20, 30, 40)];// 边界 调整
    
    // 1 bezierPath 边界
    UIBezierPath *bezierPath1 = [UIBezierPath bezierPathWithArcCenter:CGPointMake(CGRectGetWidth(self.view.bounds)/2, CGRectGetHeight(self.view.bounds)) radius:CGRectGetWidth(self.view.bounds)/2 startAngle:0 endAngle:2*M_PI clockwise:YES];
    [self.collision addBoundaryWithIdentifier:@"bezierPath1" forPath:bezierPath1];
    
    // 2 point1 - point2 边界
    [self.collision addBoundaryWithIdentifier:@"point1_point2" fromPoint:CGPointMake(0, 300) toPoint:CGPointMake(CGRectGetWidth(self.view.bounds), 400)];
    

// 注意 获取 和 remove
    NSArray *boundarys = self.collision.boundaryIdentifiers;
    [self.collision removeAllBoundaries];
    

• delegate

- (void)collisionBehavior:(UICollisionBehavior *)behavior beganContactForItem:(id )item1 withItem:(id )item2 atPoint:(CGPoint)p {
    
}
- (void)collisionBehavior:(UICollisionBehavior *)behavior endedContactForItem:(id )item1 withItem:(id )item2 {
    
}
- (void)collisionBehavior:(UICollisionBehavior*)behavior beganContactForItem:(id )item withBoundaryIdentifier:(nullable id )identifier atPoint:(CGPoint)p {
    
}
- (void)collisionBehavior:(UICollisionBehavior*)behavior endedContactForItem:(id )item withBoundaryIdentifier:(nullable id )identifier {
    
}

UIAttachmentBehavior 依附，跟随

• 正常使用

    // 1 可以跟锚点 2 可以item 与 item
    self.attach = [[UIAttachmentBehavior alloc] initWithItem:self.view1 attachedToItem:self.view2];
    self.attach.length = 100;// 距离
    self.attach.damping = 0.3;// 阻尼系数（阻碍变化）
    self.attach.frequency = 0.5;// 振动频率，（变化速度）
    
//    self.attach.anchorPoint = CGPointMake(100, 100);

    [self.animator addBehavior:self.attach];
// 2者在其他动画作用下保持相互作用力，比如某一个添加重力效果。

• iOS 9

UIKIT_EXTERN const UIFloatRange UIFloatRangeZero NS_AVAILABLE_IOS(9_0);
UIKIT_EXTERN const UIFloatRange UIFloatRangeInfinite NS_AVAILABLE_IOS(9_0);
UIKIT_EXTERN BOOL UIFloatRangeIsInfinite(UIFloatRange range) NS_AVAILABLE_IOS(9_0);
UIKIT_EXTERN BOOL UIFloatRangeIsEqualToRange(UIFloatRange range, UIFloatRange otherRange) NS_AVAILABLE_IOS(9_0);

+ (instancetype)slidingAttachmentWithItem:(id )item1 attachedToItem:(id )item2 attachmentAnchor:(CGPoint)point axisOfTranslation:(CGVector)axis NS_AVAILABLE_IOS(9_0);

+ (instancetype)slidingAttachmentWithItem:(id )item attachmentAnchor:(CGPoint)point axisOfTranslation:(CGVector)axis NS_AVAILABLE_IOS(9_0);

+ (instancetype)limitAttachmentWithItem:(id )item1 offsetFromCenter:(UIOffset)offset1 attachedToItem:(id )item2 offsetFromCenter:(UIOffset)offset2 NS_AVAILABLE_IOS(9_0);

+ (instancetype)fixedAttachmentWithItem:(id )item1 attachedToItem:(id )item2 attachmentAnchor:(CGPoint)point NS_AVAILABLE_IOS(9_0);

+ (instancetype)pinAttachmentWithItem:(id )item1 attachedToItem:(id )item2 attachmentAnchor:(CGPoint)point NS_AVAILABLE_IOS(9_0);

@property (readwrite, nonatomic) CGFloat frictionTorque NS_AVAILABLE_IOS(9_0); // default is 0.0
@property (readwrite, nonatomic) UIFloatRange attachmentRange NS_AVAILABLE_IOS(9_0); // default is UIFloatRangeInfinite

UISnapBehavior

   self.snap = [[UISnapBehavior alloc] initWithItem:self.view1 snapToPoint:CGPointMake(100, 100)];
   self.snap.damping = 0.3;// 振动频率

UIPushBehavior

    self.push = [[UIPushBehavior alloc] init];
    
    self.push.active = YES;// 是否激活
    self.push.angle = M_PI/4;// 方向
    self.push.magnitude = 0.5;// 力
    
//    self.push.pushDirection = CGVectorMake(1, 2);// 矢量
    

UIDynamicBehavior 以上运动行为的 父类

可以整合上面几种行为到一起

• (void)addChildBehavior:(UIDynamicBehavior *)behavior;

其他

直接使用好像确实很少。简单使用如上。

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