我不断收到一个空引用异常

Question

尝试创建实例化游戏对象的方法，然后存储该新游戏对象的PowerUp脚本组件。

    private void CreatePowerUp(float spawnPosX, float spawnPosZ)
    {
        PowerUp[] temp = powerUpList;

        Debug.Log("powerUpCount: " + powerUpCount);
        powerUpCount++;
        powerUpList = new PowerUp[powerUpCount];

        Debug.Log("powerUpCount: " + powerUpCount);
        for (int i = 0; i < powerUpCount - 1; i++)
        {
            powerUpList[i] = temp[i];
        }
        Debug.Log("lastPowerUp " + lastPowerUp);

        GameObject newObject = Instantiate(powerUpPrefab, new Vector3(spawnPosX, 0, spawnPosZ), powerUpPrefab.transform.rotation);
        powerUpList[0] = newObject.GetComponent<PowerUp>();

        powerUpList[0].existIndex = lastPowerUp; //FIX ME: NULL REFERENCE EXCEPTION
    }