Long.getLong（）失败，返回null到有效的字符串

问题描述

我已经花了近两年的调试时间什么似乎极不可能。我已经剥离辅助机器人活动的方法，正是这一点：

I've spent the past two hours debugging what seems extremely unlikely. I've stripped the method of a secondary Android Activity to exactly this:

public void onClick(View v) {
        String str = "25";
        long my_long = Long.getLong(str);
} // onClick (v)

，是的，我得到了良好的醇崩溃NullPointerException异常：

And yeah, I get a crash with the good ol' NullPointerException:

二月九号至11号：02：50.444：ERROR / AndroidRuntime（1588）：未捕获的处理程序：螺纹主力退出，由于未捕获的异常二月九号至11日：02：50.464：ERROR / AndroidRuntime（1588）：显示java.lang.NullPointerException

09-11 02:02:50.444: ERROR/AndroidRuntime(1588): Uncaught handler: thread main exiting due to uncaught exception09-11 02:02:50.464: ERROR/AndroidRuntime(1588): java.lang.NullPointerException

它看起来像（其它测试）的Long.getLong（str）返回NULL，这是推动我疯狂。我在想什么？

It looks like (from other tests) that Long.getLong(str) returns NULL, which is driving me bonkers. WHAT AM I MISSING?

在此先感谢。我好与愚蠢缺少明显的，但我的神智就行了。

Thanks in advance. I'm okay with stupidly missing the obvious, but my sanity is on the line.

推荐答案

您丢失的事实， Long.getLong（字符串str）是不是应该分析字符串一个长，而是返回一个系统属性按该字符串psented重新$ P $的长期价值。正如其他人所说，你真正需要的是的Long.parseLong（字符串str）。

You are missing the fact that Long.getLong(String str) is not supposed to parse a String to a long, but rather to return a long value of a system property represented by that string. As others have suggested, what you actually need is Long.parseLong(String str).

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