java_lang_IllegalArgumentException怎么办？

问题分析：
根据Android官方文档，当方法接收到了一个不合法或不正确的参数时会抛出此类异常。
解决方案：
因为参数不合法导致抛出IllegalArgumentException，请根据堆栈信息描述的出错的函数参数，按照要求传入正确的参数。
代码示例：

1. [backcolor=transparent]  [backcolor=transparent]public[backcolor=transparent] [backcolor=transparent]static[backcolor=transparent] [backcolor=transparent]void[backcolor=transparent] getUserAgent[backcolor=transparent]([backcolor=transparent]Context[backcolor=transparent] context[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]{
2. [backcolor=transparent]    [backcolor=transparent]WebView[backcolor=transparent] webview [backcolor=transparent]=[backcolor=transparent] [backcolor=transparent]new[backcolor=transparent] [backcolor=transparent]WebView[backcolor=transparent]([backcolor=transparent]context[backcolor=transparent]);
3. [backcolor=transparent]    [backcolor=transparent]WebSettings[backcolor=transparent] settings [backcolor=transparent]=[backcolor=transparent] webview[backcolor=transparent].[backcolor=transparent]getSettings[backcolor=transparent]();
4. [backcolor=transparent]    userAgent [backcolor=transparent]=[backcolor=transparent] settings[backcolor=transparent].[backcolor=transparent]getUserAgentString[backcolor=transparent]();
5. [backcolor=transparent]    [backcolor=transparent]Log[backcolor=transparent].[backcolor=transparent]i[backcolor=transparent]([backcolor=transparent]"UserAgent："[backcolor=transparent] [backcolor=transparent]+[backcolor=transparent] userAgent[backcolor=transparent]);
6. [backcolor=transparent]  [backcolor=transparent]}

1. [backcolor=transparent]  java[backcolor=transparent].[backcolor=transparent]lang[backcolor=transparent].[backcolor=transparent]IllegalArgumentException[backcolor=transparent]:[backcolor=transparent] HTTP parameters may [backcolor=transparent]not[backcolor=transparent] be [backcolor=transparent]null
2. [backcolor=transparent]    at org[backcolor=transparent].[backcolor=transparent]apache[backcolor=transparent].[backcolor=transparent]http[backcolor=transparent].[backcolor=transparent]params[backcolor=transparent].[backcolor=transparent]HttpProtocolParams[backcolor=transparent].[backcolor=transparent]getUserAgent[backcolor=transparent]([backcolor=transparent]HttpProtocolParams[backcolor=transparent].[backcolor=transparent]java[backcolor=transparent]:[backcolor=transparent]150[backcolor=transparent])
3. [backcolor=transparent]    at org[backcolor=transparent].[backcolor=transparent]apache[backcolor=transparent].[backcolor=transparent]http[backcolor=transparent].[backcolor=transparent]impl[backcolor=transparent].[backcolor=transparent]client[backcolor=transparent].[backcolor=transparent]AbstractHttpClient[backcolor=transparent].[backcolor=transparent]isMoMMS[backcolor=transparent]([backcolor=transparent]AbstractHttpClient[backcolor=transparent].[backcolor=transparent]java[backcolor=transparent]:[backcolor=transparent]790[backcolor=transparent])
4. [backcolor=transparent]    at org[backcolor=transparent].[backcolor=transparent]apache[backcolor=transparent].[backcolor=transparent]http[backcolor=transparent].[backcolor=transparent]impl[backcolor=transparent].[backcolor=transparent]client[backcolor=transparent].[backcolor=transparent]AbstractHttpClient[backcolor=transparent].[backcolor=transparent]execute[backcolor=transparent]([backcolor=transparent]AbstractHttpClient[backcolor=transparent].[backcolor=transparent]java[backcolor=transparent]:[backcolor=transparent]563[backcolor=transparent])
5. [backcolor=transparent]    at org[backcolor=transparent].[backcolor=transparent]apache[backcolor=transparent].[backcolor=transparent]http[backcolor=transparent].[backcolor=transparent]impl[backcolor=transparent].[backcolor=transparent]client[backcolor=transparent].[backcolor=transparent]AbstractHttpClient[backcolor=transparent].[backcolor=transparent]execute[backcolor=transparent]([backcolor=transparent]AbstractHttpClient[backcolor=transparent].[backcolor=transparent]java[backcolor=transparent]:[backcolor=transparent]520[backcolor=transparent])
6. [backcolor=transparent]    at org[backcolor=transparent].[backcolor=transparent]apache[backcolor=transparent].[backcolor=transparent]http[backcolor=transparent].[backcolor=transparent]impl[backcolor=transparent].[backcolor=transparent]client[backcolor=transparent].[backcolor=transparent]AbstractHttpClient[backcolor=transparent].[backcolor=transparent]execute[backcolor=transparent]([backcolor=transparent]AbstractHttpClient[backcolor=transparent].[backcolor=transparent]java[backcolor=transparent]:[backcolor=transparent]498[backcolor=transparent])
7. [backcolor=transparent]    at com[backcolor=transparent].[backcolor=transparent]g[backcolor=transparent].[backcolor=transparent]utils[backcolor=transparent].[backcolor=transparent]HttpClientUtil[backcolor=transparent].[backcolor=transparent]post[backcolor=transparent]([backcolor=transparent]HttpClientUtil[backcolor=transparent].[backcolor=transparent]java[backcolor=transparent]:[backcolor=transparent]99[backcolor=transparent])
8. [backcolor=transparent]    at com[backcolor=transparent].[backcolor=transparent]g[backcolor=transparent].[backcolor=transparent]utils[backcolor=transparent].[backcolor=transparent]LoadDataFromServer$2[backcolor=transparent].[backcolor=transparent]run[backcolor=transparent]([backcolor=transparent]LoadDataFromServer[backcolor=transparent].[backcolor=transparent]java[backcolor=transparent]:[backcolor=transparent]195[backcolor=transparent])