NullPointerException表示你传递的其中一个变量为null，但是代码试图使用它，就像它不是。

A NullPointerException means that one of the variables you are passing is null, but the code tries to use it like it is not.

例如，如果我这样做：

Integer myInteger = null;
int n = myInteger.intValue();

代码尝试获取myInteger的intValue，但由于它为null，因此它没有：发生空指针异常。

The code tries to grab the intValue of myInteger, but since it is null, it does not have one: a null pointer exception happens.

这意味着你的getTask方法期望某些东西不是null，但你传递的是null。弄清楚getTask需要什么并传递它想要的东西！

What this means is that your getTask method is expecting something that is not a null, but you are passing a null. Figure out what getTask needs and pass what it wants!