MonoBehaviour.IsInvoking 是否调用

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
	public Rigidbody projectile;
	void Update() {
		if (Input.GetKeyDown(KeyCode.Space) && !IsInvoking("LaunchProjectile"))
			Invoke("LaunchProjectile", 2);

	}
	void LaunchProjectile() {
		Rigidbody instance = Instantiate(projectile);
		instance.velocity = Random.insideUnitSphere * 5;
	}
}

// Instantiates a project after 2 seconds when Space key was pressed
// and it will only call the function after the function has ended its execution
// 按下空格键2秒后实例化一个炮弹,在该函数执行完毕之前仅调用此函数
var projectile : Rigidbody;

function Update() {
	if(Input.GetKeyDown(KeyCode.Space) && !IsInvoking("LaunchProjectile"))
		Invoke("LaunchProjectile", 2);
}

function LaunchProjectile () {
	var instance : Rigidbody = Instantiate(projectile);
	instance.velocity = Random.insideUnitSphere * 5;
}