UIDynamic - 推动行为: UIPushBehavior

用途:

从一个点移动到另外一个点;

相关属性:

mode : UIPushBehaviorModeContinuous  //推移模式

angle : setAngle  //推移角度

magnitude : setMagnitude  //速度   每1个magnigude将会引起100/平方秒的加速度

图片说明:

p1 : squareView的中心点  p2 : 单击的点

促使squareView朝着p2移动，因为加了UICollisionBehavior，所以移动时又不会超过边界

代码:

 //

 //  YFPushBehaviorViewController.m

 //  BigShow1949

 //

 //  Created by apple on 16/8/25.

 //  Copyright © 2016年 BigShowCompany. All rights reserved.

 //

 #import "YFPushBehaviorViewController.h"

 @interface YFPushBehaviorViewController ()

 @property(nonatomic,strong)UIDynamicAnimator *animator;

 @property (nonatomic, strong) UIView *squareView;

 @property (nonatomic, strong) UIPushBehavior *pushBehavior;

 @end

 @implementation YFPushBehaviorViewController

 - (void)viewDidLoad {

     [super viewDidLoad];

     self.view.backgroundColor = [UIColor whiteColor];

 }

 - (void)viewDidAppear:(BOOL)animated{

     [super viewDidAppear:animated];

     // 创建一个正方形

     self.squareView =[[UIView alloc] initWithFrame: CGRectMake(0.0f, 0.0f, 80.0f, 80.0f)];

     self.squareView.backgroundColor = [UIColor greenColor];

     self.squareView.center = self.view.center;

     [self.view addSubview:self.squareView];

     // 视图单机手势

     [self createGestureRecognizer];

     [self createAnimatorAndBehaviors];

 }

 - (void) createGestureRecognizer{

     UITapGestureRecognizer *tapGestureRecognizer =

     [[UITapGestureRecognizer alloc] initWithTarget:self  action:@selector(handleTap:)];

     [self.view addGestureRecognizer:tapGestureRecognizer];

 }

 - (void) handleTap:(UITapGestureRecognizer *)paramTap{

     CGPoint tapPoint = [paramTap locationInView:self.view];  //p2

     CGPoint squareViewCenterPoint = self.squareView.center;  //p1

     CGFloat deltaX = tapPoint.x - squareViewCenterPoint.x;

     CGFloat deltaY = tapPoint.y - squareViewCenterPoint.y;

     CGFloat angle = atan2(deltaY, deltaX);

     [self.pushBehavior setAngle:angle];  //推移的角度

     //勾股

     CGFloat distanceBetweenPoints =

     sqrt(pow(tapPoint.x - squareViewCenterPoint.x, 2.0) +

          pow(tapPoint.y - squareViewCenterPoint.y, 2.0));

     //double pow(double x, double y）;计算以x为底数的y次幂

     //double sqrt (double);开平方

     //推力的大小（移动速度）

     [self.pushBehavior setMagnitude:distanceBetweenPoints / 50.0f];

     //每1个magnigude将会引起100/平方秒的加速度，这里分母越大，速度越小

 }

 - (void) createSmallSquareView{

     self.squareView =[[UIView alloc] initWithFrame: CGRectMake(0.0f, 0.0f, 80.0f, 80.0f)];

     self.squareView.backgroundColor = [UIColor greenColor];

     self.squareView.center = self.view.center;

     [self.view addSubview:self.squareView];

 }

 - (void) createAnimatorAndBehaviors{

     self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];

     /* Create collision detection */

     UICollisionBehavior *collision = [[UICollisionBehavior alloc]

                                       initWithItems:@[self.squareView]];

     collision.translatesReferenceBoundsIntoBoundary = YES;

     self.pushBehavior = [[UIPushBehavior alloc]

                          initWithItems:@[self.squareView]

                          mode:UIPushBehaviorModeContinuous];

     [self.animator addBehavior:collision];

     [self.animator addBehavior:self.pushBehavior];

 }

 @end