如何在NSObject类中添加动态行为: Swift

Question

我正在尝试使用UIDynamicAnimator在NSObject类中使用NSObject类使用UISnapBehaviour创建一个动态行为的自定义警报视图，同时将UISnapBehaviour添加到NSObject类中的视图中，init方法snap行为不起作用，例如，查看下面的代码

import UIKit

class DynamicBehaviour: NSObject {

var Animator:UIDynamicAnimator!
var TargetView:UIView!
var TestView:UIView!

override init() {
    super.init()
}

init(SourceViews:UIView) {
    super.init()

    TestView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
    TestView.backgroundColor = UIColor.blueColor()
    TargetView.addSubview(TestView)

    Animator = UIDynamicAnimator(referenceView: TargetView)
    let snapBehavior: UISnapBehavior = UISnapBehavior(item: TestView, snapToPoint: TargetView.center)
    Animator.addBehavior(snapBehavior)

  }
}

"TestView“作为子视图添加到”目标“中，但是快照行为不起作用。

我在ObjectiveC中尝试了相同的代码

#import "DynamicBehaviour.h"
#import <UIKit/UIKit.h>

@interface DynamicBehaviour ()
@property(nonatomic,strong)UISnapBehavior * Snap_behaviour;
@property (nonatomic,strong)UIDynamicAnimator * Animator;


@end
@implementation DynamicBehaviour

-(instancetype)initWithSourceView:(UIView *)TargetView{
   if (self = [super init]) {
      UIView * TestView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100,     100)];
      TestView.backgroundColor = [UIColor blueColor];
      [TargetView addSubview:TestView];

      self.Animator = [[UIDynamicAnimator    alloc]initWithReferenceView:TargetView];
       self.Snap_behaviour = [[UISnapBehavior alloc]initWithItem:TestView snapToPoint:TargetView.center];
       [self.Animator addBehavior:self.Snap_behaviour];
   }
  return self;
  }


 @end

它工作得很好，"TestView“冲到了TargetView.I的中心，我不知道快速代码有什么问题。

以下是我尝试过的：

1. 在UIViewController类中编码时，动态效果很好，只有在NSObject子类中才存在问题。
2. 我尝试过其他的动态行为，如UIGravityBehavior，同样的问题也在迅速地存在。
3. 在ObjectiveC对象类中完成相同的示例工作--它的工作很好--我也附加了工作的ObjC代码。

似乎这个问题可能存在于init方法或变量解密不确定，但我不知道如何解决这个问题。我在网上读过很多文章。我还搜索过StackOverflow。请帮帮忙。

Answer 1

Swift中的代码与Objective代码不完全相同:Objective代码有很强的引用Snap_behaviour，但是Swift代码只有本地只读变量。以下是Swift的等价物：

class DynamicBehaviour: NSObject {

    var Animator:UIDynamicAnimator!
    var snapBehaviour:UISnapBehavior!
    var TargetView:UIView!
    var TestView:UIView!

    override init() {
        super.init()
    }

    init(SourceViews:UIView) {
        super.init()

        TestView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
        TestView.backgroundColor = UIColor.blueColor()
        TargetView.addSubview(TestView)

        Animator = UIDynamicAnimator(referenceView: TargetView)
        snapBehaviour = UISnapBehavior(item: TestView, snapToPoint: TargetView.center)
        Animator.addBehavior(snapBehaviour)

    }
}

通常，我使用UIDynamicBehaviour作为组合行为的基类，如

class CombinedBehavior: UIDynamicBehavior {

    lazy var collider: UICollisionBehavior = {
        let lazilyCreatedCollider = UICollisionBehavior()
        lazilyCreatedCollider.translatesReferenceBoundsIntoBoundary = true
        lazilyCreatedCollider.collisionMode = UICollisionBehaviorMode.Everything
        return lazilyCreatedCollider
    }()

    lazy var itemBehavior: UIDynamicItemBehavior = {
        let lazilyCreatedBehavior = UIDynamicItemBehavior()
        lazilyCreatedBehavior.allowsRotation = true
        lazilyCreatedBehavior.elasticity = 0
        lazilyCreatedBehavior.resistance = 100
        lazilyCreatedBehavior.angularResistance = 100
        lazilyCreatedBehavior.friction = 100
        return lazilyCreatedBehavior
    }()

    override init() {
        super.init()
        addChildBehavior(collider)
        addChildBehavior(itemBehavior)
    }

    func addBarrier(path: UIBezierPath, named name: String) {
        collider.removeBoundaryWithIdentifier(name)
        collider.addBoundaryWithIdentifier(name, forPath: path)
    }

    func addView(view: UIView) {
        dynamicAnimator?.referenceView?.addSubview(view)
        collider.addItem(view)
        itemBehavior.addItem(view)
    }

    func removeView(view: UIView) {
        collider.removeItem(view)
        itemBehavior.removeItem(view)
        view.removeFromSuperview()
    }
}

将此代码放入控制器中。

lazy var animator: UIDynamicAnimator = {
    let lazilyCreatedDynamicAnimator = UIDynamicAnimator(referenceView: self.view) // or any view you needed
    // if you need delegate in your controller uncomment this
    //        lazilyCreatedDynamicAnimator.delegate = self
    return lazilyCreatedDynamicAnimator
}()

var combinedBehavior = CombinedBehavior()

override func viewDidLoad() {
    // your other code
    animator.addBehavior(combinedBehavior)
}