What is the power effect?

What is the power effect?

First, a UIDynamicAnimator animated painter will give him a UIDynamicBehavior power effect, and add the UIDynamicItem (UIView) power element to the power effect.

Dynamic elements: all elements that comply with the UIDynamicItem protocol can be regarded as dynamic elements.

The painter of the UIDynamicAnimator animation needs a range ()

Their link structure is as follows:

Dynamic Behavior:

1. Introduction: belongs to UIKit

(1) What is dynamic behavior? -> Simulate mechanics-related animation and Interaction Systems in the real world

(2) Possible effects:-> gravity, collision, adsorption, push, capture, and combination

(3) iOS9 UIDynamicItemGroup can uniformly Add dynamic behavior to a group of elements

(4) iOS9 can be defined as a spherical contact with another border or element.

2. Class Name introduction:

(1) UIDynamicAnimator: animation creator of the Dynamic Effect

Attribute introduction:

① InitWithReferenceView: initialize a power effect consumer and create a reference View

② AddBehavior: Add dynamic behavior

③ RemoveBehavior: Remove a dynamic behavior.

④ RemoveAllBehaviors remove all dynamic behaviors

⑤ Delegate proxy

(2) UIDynamicBehavior: the animation action of the dynamic effect. The animation action of the dynamic effect will affect the attribute of the dynamic element (frame)

There are six major dynamic behaviors:

1 UIGravityBehavior gravity effect Behavior

① InitWithItems: initializes the gravity effect behavior and specifies the target object

② AddItem: add the target object of gravity effect

③ RemoveItem: remove the target object.

④ GravityDirection direction of gravity

CGVector: struct value of the vector: 0-1

X: horizontal gravity

Y: vertical gravity

The number of pixels dropped by 1000 per second due to acceleration and radians

⑤ Angle: change the angle of gravity effect

6 magn133: The acceleration level is 1.0, which indicates that the acceleration is 1000 points/second 2.

7. setAngle: magnangle: Set the angle and speed of the gravity direction.

2 UICollisionBehavior collision Behavior

① InitWithItems: initialization

② CollisionMode: collision style (Mode)

UICollisionBehaviorModeItems element collision

UICollisionBehaviorModeBoundaries border collision

UICollisionBehaviorModeEverything

③ CollisionDelegate: proxy

④ Proxy method called during element collision

-(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;

⑤ Proxy method called when the elements collide with the border

-(Void) collisionBehavior :( UICollisionBehavior *) behavior beganContactForItem :( id <UIDynamicItem>) item identifier :( nullable id <NSCopying>) identifier atPoint :( CGPoint) p;

-(Void) collisionBehavior :( UICollisionBehavior *) behavior endedContactForItem :( id <UIDynamicItem>) item withBoundaryIdentifier :( nullable id <NSCopying>) identifier;

⑥ AddBoundaryWithIdentifier: forPath: Add path as border

7-(nullable UIBezierPath *) boundaryWithIdentifier :( id <NSCopying>) identifier

⑧ AddBoundaryWithIdentifier: fromPoint: toPoint: add a line as the border

⑨ RemoveBoundaryWithIdentifier

Whether ⑩ translatesReferenceBoundsIntoBoundary uses the reference view as the Boundary

⑪ SetTranslatesReferenceBoundsIntoBoundaryWithInsets: Set the inner distance of the reference view.

3 uipus?havior promotes Behavior

4 UISnapBehavior moved fast

5 UIAttachmentBehavior appendix and Behavior

6 UIDynamicItemBehavior Element Behavior

(3) UIDynamicItem dynamic element

The above is an introduction to dynamic behaviors. The specific operations are as follows:

First, create a UIImageView in Main. sroryBoard, set the full screen attribute, allow user interaction, and image. Drag the ImageView to the ViewController. m file.

@ Interface

# Import "ViewController. h "@ interface ViewController () <UIDynamicAnimatorDelegate, UICollisionBehaviorDelegate> // The Force effect element @ property (nonatomic, strong) UIImageView * ballItem; @ property (weak, nonatomic) IBOutlet UIImageView * bgView; @ property (nonatomic, strong) UIDynamicAnimator * animatior; // the image that appears when it hits the border @ property (nonatomic, strong) UIImageView * dungView; @ end @ implementation ViewController-(void) viewDidLoad {[super viewDidLoad]; [self. bgView addSubview: self. ballItem];}-(void) touchesBegan :( NSSet <UITouch *> *) touches withEvent :( UIEvent *) event {self. ballItem. center = [[touches anyObject] locationInView: self. view];}-(void) touchesMoved :( NSSet <UITouch *> *) touches withEvent :( UIEvent *) event {self. ballItem. center = [[touches anyObject] locationInView: self. view];} // After dragging, let the ball drop-(void) touchesEnded :( NSSet <UITouch *> *) touches withEvent :( UIEvent *) event {NSLog (@ "Y: % f ", self. ballItem. frame. origin. y); [self gravityBehavior]; [self collisionBehavior];} # pragma mark ------- gravity effect-(void) gravityBehavior {// remove the previous effect [self. animatior removeAllBehaviors]; UIGravityBehavior * gravityBehavior = [[UIGravityBehavior alloc] initWithItems: @ [self. ballItem]; gravityBehavior. gravityDirection = CGVectorMake (0.0, 1.0); // gravity direction // gravityBehavior. angle = 30 * M_PI/180; // acceleration will affect the descent speed gravityBehavior. magn133 = 1.5; // Add the gravity effect to the operator of the dynamic effect [self. animatior addBehavior: gravityBehavior] ;}# pragma mark ----- collision detection behavior-(void) collisionBehavior {comment * collisionBehavior = [[UICollisionBehavior alloc] initWithItems: @ [self. ballItem]; // set the collision style (pattern) collisionBehavior. collisionMode = UICollisionBehaviorModeEverything; // whether to use the reference view as the boundary // collisionBehavior. inline = YES; // circle // UIBezierPath * path = [UIBezierPath paths: CGRectMake (20,300,300,300) cornerRadius: 150]; // [collisionBehavior addBoundaryWithIdentifier: @ "round" forPath: path]; // draw line [collisionBehavior addBoundaryWithIdentifier: @ "line" fromPoint: CGPointMake (0,680) toPoint: CGPointMake (414,680)]; collisionBehavior. collisionDelegate = self; [self. animatior addBehavior: collisionBehavior] ;}# pragma mark -------- collision behavior proxy method // collision between elements-(void) collisionBehavior :( behavior *) behavior beganContactForItem :( id <UIDynamicItem>) item1 withItem :( id <UIDynamicItem>) item2 atPoint :( CGPoint) p {}-(void) collisionBehavior :( UICollisionBehavior *) behavior endedContactForItem :( id <UIDynamicItem>) item1 withItem :( id <UIDynamicItem>) item2 {}// collision between the element and the border-(void) collisionBehavior :( UICollisionBehavior *) behavior beganContactForItem :( id <UIDynamicItem>) item withBoundaryIdentifier :( nullable id <NSCopying>) identifier atPoint :( CGPoint) p {NSLog (@ ""); self. dungView. center = CGPointMake (p. x-20, p. y-20); // [self. dungView addSubview: self. ballItem]; [self. bgView exchangeSubviewAtIndex: 1 withSubviewAtIndex: 0];}-(void) collisionBehavior :( behavior *) behavior :( id <UIDynamicItem>) item identifier :( nullable id <NSCopying>) identifier {NSLog (@ "end contact border"); [behavior removeBoundaryWithIdentifier: @ "line"]; [self collisionBehavior] ;}# pragma mark -------- operator (Power Effect operator) -(void) dynamicAnimatorWillResume :( UIDynamicAnimator *) animator {NSLog (@ "");}-(void) dynamicAnimatorDidPause :( UIDynamicAnimator *) animator {NSLog (@ "pause");}-(UIImageView *) ballItem {if (_ ballItem) {return _ ballItem;} _ ballItem = [[UIImageView alloc] initWithFrame: CGRectMake (100, 50, 50, 50)]; _ ballItem. image = [UIImage imageNamed: @ ""]; return _ ballItem;}-(UIDynamicAnimator *) animatior {if (_ animatior) {return _ animatior ;} _ animatior = [[UIDynamicAnimator alloc] initWithReferenceView: self. view]; _ animatior. delegate = self; return _ animatior;}-(UIImageView *) dungView {if (_ dungView) {return _ dungView;} UIImage * image = [UIImage imageNamed: @ "keng"]; _ dungView = [[UIImageView alloc] initWithFrame: CGRectMake (0,680, image. size. width/2.5, image. size. height/2.5)]; _ dungView. image = image; [self. bgView addSubview: _ dungView]; return _ dungView;} @ end

The running effect is that after you drag the ball, a pitfall will appear. ,

The effect is as follows:

Initial Location

Status of Drop completed