Question

我似乎无法弄清楚它正在讨论哪个可选值或为什么我收到此错误。我检查了我的分数整数，并确保我宣布它的值为0，直到它与敌人接触。在模拟器中，计数器计算前4或5个敌人然后崩溃。

var score = Int? ()
var scoreLabel = UILabel ()
 override func didMoveToView(view: SKView) {

    scoreLabel.text = "\(score)"
    scoreLabel = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 
    20))
    scoreLabel.textColor = UIColor.blackColor()

    score = nil
    if score == nil {
        score = 0
        scoreLabel.text = "\(score!)"
}
func didBeginContact(contact: SKPhysicsContact) {

    let firstBody : SKPhysicsBody = contact.bodyA
    let secondBody : SKPhysicsBody = contact.bodyB

    if ((firstBody.categoryBitMask == PhysicsCategory.bullet) &&  
(secondBody.categoryBitMask == PhysicsCategory.enemy) ||
        (firstBody.categoryBitMask == PhysicsCategory.enemy) && 
(secondBody.categoryBitMask == PhysicsCategory.bullet)) {
 //i get the error next line            
collisionWithBullet((firstBody.node as! SKSpriteNode), 
bullet: (secondBody.node as! SKSpriteNode))
    }
}

func collisionWithBullet(enemy: SKSpriteNode, bullet: SKSpriteNode){

    score? += 1
    scoreLabel.text = "\(score!)"
    enemy.removeFromParent ()
    bullet.removeFromParent ()

}

Answer 1

将分数设为非可选，并将0设为默认分数

var score = 0
var scoreLabel = UILabel ()

override func didMoveToView(view: SKView) {

scoreLabel.text = "\(score)"
scoreLabel = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 
20))
scoreLabel.textColor = UIColor.blackColor()

//指定nil得分并检查nil ???

//score = nil
//if score == nil {
 //   score = 0
 //  scoreLabel.text = "\(score!)"
//}

score = 0
scoreLabel.text = "\(score!)"

func didBeginContact(contact: SKPhysicsContact) {

let firstBody : SKPhysicsBody = contact.bodyA
let secondBody : SKPhysicsBody = contact.bodyB

if ((firstBody.categoryBitMask == PhysicsCategory.bullet) &&  
(secondBody.categoryBitMask == PhysicsCategory.enemy) ||
    (firstBody.categoryBitMask == PhysicsCategory.enemy) && 
(secondBody.categoryBitMask == PhysicsCategory.bullet)) {
//i get the error next line            
collisionWithBullet((firstBody.node as! SKSpriteNode), 
bullet: (secondBody.node as! SKSpriteNode))
}
}

func collisionWithBullet(enemy: SKSpriteNode, bullet: SKSpriteNode){

score += 1 // score is no more optional. default score is 0
scoreLabel.text = "\(score!)"
enemy.removeFromParent ()
bullet.removeFromParent ()

}

致命错误：在物理联系人中展开可选值时意外发现nil

1 个答案: