我正在使用以下网站查找海拔：

这以XML格式提供了93.7665481567383格式的结果.

有人知道为我的Android程序提取此数据的快速简单的方法吗？

我尝试了以下操作,但输出一直为“ null”.

HttpURLConnection connection = null;

URL serverAddress = null;

serverAddress = new URL("http://gisdata.usgs.gov/xmlwebservices2/elevation_service.asmx/getElevation?X_Value=-78.85834070853889&Y_Value=43.869369104504585&Elevation_Units=METERS&Source_Layer=-1&Elevation_Only=true");

connection = null;

connection = (HttpURLConnection)serverAddress.openConnection();

connection.setRequestMethod("GET");

connection.setDoOutput(true);

connection.setReadTimeout(10000);

connection.connect();

BufferedReader rd = new BufferedReader(new

InputStreamReader(connection.getInputStream()));

StringBuilder sb = new StringBuilder();

String line = null;

line = rd.readLine();

while ((line = rd.readLine()) != null)

{

sb.append(line + '\n');

}

当我输出sb.toString()我得到Null

有任何想法吗？

解决方法:

我建议自己尝试解析XML,而不是尝试从Buffer中读取它,而无需自己亲自尝试.为此,您将需要了解XML树结构,因为您将基于Node进行阅读.例如：

// Data members

private URL URL;

private InputStream stream;

private DocumentBuilder builder;

private Document document;

private Element root;

private NodeList nodeList;

URL = new URL(url); // The URL of the site you posted goes here.

stream = URL.openStream();

// Set up and initialize the document.

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

dbf.setIgnoringElementContentWhitespace(true);

builder = dbf.newDocumentBuilder();

document = builder.parse(stream);

document.getDocumentElement().normalize();

root = document.getDocumentElement();

nodeList = root.getChildNodes();

// The number of calls to 'getFirstChild()' will vary with the complexity of

// your XML tree. Also, 'i' could vary as well, depending on which Node off

// of the root you want to access.

String number = nodeList.item(i).getFirstChild().getFirstChild().getNodeValue();

这似乎很令人困惑,但是让我给您一个XML示例.

Train Station

8 Main Street

Blue

Drugstore

14 Howard Boulevard

Yellow

每个建筑物代表一个不同的值,该值作为参数传递给“ .item(i)”.要访问有关第一个Building的信息,请传递一个值0.使用’.getFirstChild()’方法访问Building的子级,但是仅返回Node.如果需要文本“ Drugstore”,则必须遍历XML树到第二个项目的第一个孩子的数据. nodeList.item(1).getFirstChild().getNodeValue();

希望对您有所帮助！！

标签：xml,android,xml-parsing

来源： https://codeday.me/bug/20191101/1986151.html