如何在Swift中设置速度

下面是 Swift中Sprite Kit中的Enemy节点.我已经为节点设置了速度,但是当它产生时没有移动. Xcode没有给我任何错误,有什么我在这里做错了吗？

class Enemy: SKSpriteNode {

    init(imageNamed: String) {

        let imageTexture = SKTexture(imageNamed: imageNamed)
        super.init(texture: imageTexture, color: nil, size: imageTexture.size())

        self.name = "Enemy"

        self.physicsBody = SKPhysicsBody(rectangleOfSize: imageTexture.size())
        self.physicsBody?.dynamic = false
        self.physicsBody?.velocity = CGVectorMake(10.0,10.0)

    }
}

来自Apple的 SpriteKit documentation：

A Boolean value that indicates whether the physics body is moved by the physics simulation.

Declaration

Swift

var dynamic: Bool

Objective-C

@property(nonatomic, getter=isDynamic) BOOL dynamic

Discussion

If the value is NO, the physics body ignores all forces and impulses applied to it. This property is ignored on edge-based bodies; they are automatically static.

正如0x141E所说,你必须使你的SKPhysicsBody动态,否则它不会移动.