IOS-UI-UIDynamic（二）

UIPushBehavior :推动效果

UIAttachmentBehavior：附着效果

UISnapBehavior：迅速移动效果

一.重要的属性

UIPushBehavior :推动效果

typedef NS_ENUM(NSInteger, UIPushBehaviorMode) {

UIPushBehaviorModeContinuous, 持续的力

UIPushBehaviorModeInstantaneous 瞬间的力

} NS_ENUM_AVAILABLE_IOS(7_0);

@property (nonatomic, readonly) UIPushBehaviorMode mode; 推动效果的样式

@property (nonatomic, readwrite) BOOL active; 是否激活

@property (readwrite, nonatomic) CGFloat angle; 推动角度

@property (readwrite, nonatomic) CGFloat magnitude; 推动力量

@property (readwrite, nonatomic) CGVector pushDirection; 推动的方向

UISnapBehavior：迅速移动效果

// The point argument is expressed in the reference coordinate system

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

迅速移动效果 只能一次 添加到一个元素上  snapToPoint 让他移动到哪一个点

@property (nonatomic, assign) CGFloat damping; // damping value from 0.0 to 1.0. 0.0 is the least oscillation. damping 的范围是（0.0-1.0）

UIAttachmentBehavior：附着效果

吸附着一个视图 或者一个点  （也可以多个连接）

附着效果 一个视图与一个锚点或者另一个视图相连接的情况

附着行为描述的是两点之间的连接情况，可以模拟刚性或者弹性连接

在多个物体间设定多个UIAttachmentBehavior，可以模拟多物体连接

typedef NS_ENUM(NSInteger, UIAttachmentBehaviorType) {

UIAttachmentBehaviorTypeItems, 吸附一个元素

UIAttachmentBehaviorTypeAnchor 吸附一个点

} NS_ENUM_AVAILABLE_IOS(7_0);

设置吸附效果的样式

@property (readonly, nonatomic) UIAttachmentBehaviorType attachedBehaviorType;

@property (readwrite, nonatomic) CGPoint anchorPoint;锚点

@property (readwrite, nonatomic) CGFloat length;距离 与锚点的距离

@property (readwrite, nonatomic) CGFloat damping; // 1: critical damping  跳跃度

@property (readwrite, nonatomic) CGFloat frequency; // in Hertz   幅度

二.代码

1.推动效果

 #import "ViewController.h"

 @interface ViewController ()
 {
     UIDynamicAnimator * dynamicAnimator;
     UIView *view1;

 }
 @end

 @implementation ViewController

 - (void)viewDidLoad {
     [super viewDidLoad];
     dynamicAnimator = [[UIDynamicAnimator alloc]initWithReferenceView:self.view];
     view1 = [[UIView alloc]initWithFrame:CGRectMake(, , , )];
     view1.backgroundColor = [UIColor redColor];
     [self.view addSubview:view1];
     UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(pushView)];

     [view1 addGestureRecognizer:tap];

- (void)pushView{
    [dynamicAnimator removeAllBehaviors];//移除所有的效果
    UIPushBehavior * push = [[UIPushBehavior alloc]initWithItems:@[view1] mode:UIPushBehaviorModeContinuous];
//    mode的两个属性
    //    UIPushBehaviorModeContinuous,一直推动
//    UIPushBehaviorModeInstantaneous 瞬间推动
    push.pushDirection = CGVectorMake(, );
//    x是正右，负左。y是正下负上。
    push.magnitude = ;//量级：既是推动力大小
//设置成NO时就不再响应效果
    //    push.active = NO;
    [dynamicAnimator addBehavior:push];//把推动效果添加到效果器上
}

2.瞬间移动效果(viewDidLoad里面添加另一个点击手势)

 UITapGestureRecognizer *tap1 = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(snap:)];

    [self.view addGestureRecognizer:tap1];

之后

-(void)snap:(UITapGestureRecognizer *)send{
    [dynamicAnimator removeAllBehaviors];
//    迅速移动效果 只能一次 添加到一个元素上  snapToPoint 让他移动到哪一个点
    UISnapBehavior * snap = [[UISnapBehavior alloc]initWithItem:view1 snapToPoint:[send locationInView:self.view]];
//跳动幅度：0~1,值越小，跳动幅度越大
    snap.damping = ;
    [dynamicAnimator addBehavior:snap];

}

吸附效果

@interface ViewController ()
{
    UIDynamicAnimator * dynamicAnimator;
    UIView *view1;
     UIView *view2;
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    dynamicAnimator = [[UIDynamicAnimator alloc]initWithReferenceView:self.view];
    view1 = [[UIView alloc]initWithFrame:CGRectMake(, , , )];
    view1.backgroundColor = [UIColor redColor];

    [self.view addSubview:view1];

    view2 = [[UIView alloc]initWithFrame:CGRectMake(, , , )];
    view2.backgroundColor = [UIColor blueColor];
    [self.view addSubview:view2];

    UITapGestureRecognizer *tap2 = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(attachment:)];

    [self.view addGestureRecognizer:tap2];

}

-(void)attachment:(UITapGestureRecognizer *)send{
    [dynamicAnimator removeAllBehaviors];
//    吸附到视图的某个点
    UIAttachmentBehavior * attachment = [[UIAttachmentBehavior alloc]initWithItem:view1 offsetFromCenter:UIOffsetMake(, ) attachedToAnchor:[send locationInView:self.view]];
    attachment.length = ;//吸附范围
    attachment.damping = 0.5;
    attachment.frequency = ;
    [dynamicAnimator addBehavior:attachment];
//    两个元素吸附
//    UIAttachmentBehavior *attachment1 = [[UIAttachmentBehavior alloc]initWithItem:view1 offsetFromCenter:UIOffsetMake(50, 50) attachedToItem:view2 offsetFromCenter:UIOffsetMake(50, 50)];
//    attachment1.length = 50;//吸附范围
//    attachment1.damping = 0.5;
//    attachment1.frequency = 50;
//    [dynamicAnimator addBehavior:attachment1];

   }

另外，在iOS9之前这些效果只支持矩形。IOS9之后增加了新的属性UIDynamicItemCollisionBoundsType；因为本人的Xcode没升级，没法使用。