如何在SpriteKit中让玩家节点在跳转后站立？

import SpriteKit

class GameScene: SKScene, SKPhysicsContactDelegate {
    var playerNode: SKSpriteNode!
    
    override func didMove(to view: SKView) {
        // 创建玩家节点
        playerNode = SKSpriteNode(color: .red, size: CGSize(width: 50, height: 50))
        playerNode.position = CGPoint(x: frame.midX, y: frame.midY)
        addChild(playerNode)
        
        // 添加物理体
        playerNode.physicsBody = SKPhysicsBody(rectangleOf: playerNode.size)
        playerNode.physicsBody?.isDynamic = true
        
        // 设置物理属性
        playerNode.physicsBody?.affectedByGravity = true
        playerNode.physicsBody?.restitution = 0.5
        playerNode.physicsBody?.friction = 0.2
        
        // 设置代理
        physicsWorld.contactDelegate = self
        
        // 执行跳跃动作
        let jumpAction = SKAction.sequence([
            SKAction.applyImpulse(CGVector(dx: 0, dy: 200), duration: 0.5),
            SKAction.wait(forDuration: 0.5)
        ])
        playerNode.run(jumpAction)
    }
    
    func didEnd(_ contact: SKPhysicsContact) {
        // 监听跳跃完成
        if contact.bodyA.node == playerNode || contact.bodyB.node == playerNode {
            // 执行站立动作
            let standAction = SKAction.sequence([
                SKAction.wait(forDuration: 1.0),
                SKAction.run {
                    // 在此处执行站立后的操作
                }
            ])
            playerNode.run(standAction)
        }
    }
}