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测试节点是否连接到physicsBody swift

skphysicsbody skspritenode sprite-kit swift

gamer12 · 技术社区 · 7 年前

我将节点连接到一个contact body(SKPhysicsBody),在检测到SKSpriteNode之间的接触时调用该函数。有时,我会出错,因为它无法将节点连接到接触体,所以我测试是否存在节点以避免此类错误。但是一个警告告诉我它永远不会返回false。自从我测试之后,我再也没有出现过这样的错误,但我不确定它是否工作良好,或者它是否仍然可以发生。你知道吗?

//The actual code
func didBegin(_ contact: SKPhysicsContact) {
    if (contact.bodyA.categoryBitMask == enemyCategory) && (contact.bodyB.categoryBitMask == shootCategory){ //test if it is the contact with I want to catch
        let shootNode = contact.bodyB.node, shootNode != nil { // I test if there's a node attached to the enemyShootNode but it's supposed never to return false
            let enemyNode = contact.bodyA.node, enemyNode != nil { // I test if there's a node attached to the shootNode but it's supposed never to return false
                let enemySKNode = enemyNode as? SKSpriteNode
                let shootSKNode = shootNode as? SKSpriteNode
                // code
            }
        }
    }
}

   // The code with error
func didBegin(_ contact: SKPhysicsContact) {
    if (contact.bodyA.categoryBitMask == enemyCategory) && (contact.bodyB.categoryBitMask == shootCategory){
        let shootNode = contact.bodyB.node!
        let enemyNode = contact.bodyA.node! // The error occurs here : "fatal error: unexpectedly found nil while unwrapping an Optional value"
        let enemySKNode = enemyNode as? SKSpriteNode
        let shootSKNode = shootNode as? SKSpriteNode
     }
}

1 回复 | 直到 7 年前

gamer12 7 年前

谢谢你的建议,这个错误确实来自SKPhysics属性(didbegen函数被多次调用),但我没有设法修复。

func didBegin(_ contact: SKPhysicsContact) {
    if (contact.bodyA.categoryBitMask == enemyCategory) && (contact.bodyB.categoryBitMask == shootCategory) || (contact.bodyA.categoryBitMask == shootCategory) && (contact.bodyB.categoryBitMask == enemyCategory){
        if var shootNode = contact.bodyB.node{
            if var enemyNode = contact.bodyA.node{
                // If the enemyNode and the shootNode don't respectively correspond to 
                if contact.bodyA.categoryBitMask == shootCategory {
                    shootNode = contact.bodyA.node!
                    enemyNode = contact.bodyB.node!
                }
                let enemySKNode = enemyNode as? SKSpriteNode
                let shootSKNode = shootNode as? SKSpriteNode
            }
        }
    }
}