我尝试了一个解析和显示xml文件数据的例子，因此我遵循了parsexml教程。我用我自己的xml文件替换了这个xml文件，我存储在我的服务器上。我的xml文件是有效的，我通过加载我的chrome来检查这个。我的问题是在运行我的项目时它抛出一个错误，因为零点错误当我在xml文件附近调试我的应用程序时，它给出了找不到页面的错误。有了这个，我附上了我的logcat。任何人都可以告诉我为什么会收到此错误。我提到this但没有用。我的logcat是
12-26 02:34:20.230: E/Error:(1734): expected: /META read: HEAD (position:END_TAG </HEAD>@11:8 in java.io.StringReader@41829778)
12-26 02:34:20.230: D/AndroidRuntime(1734): Shutting down VM
12-26 02:34:20.230: W/dalvikvm(1734): threadid=1: thread exiting with uncaught exception (group=0x414c4700)
12-26 02:34:20.240: E/AndroidRuntime(1734): FATAL EXCEPTION: main
12-26 02:34:20.240: E/AndroidRuntime(1734): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.testing.mypractise/com.practise.loadimagefromxml.AndroidXMLParsingActivity}: java.lang.NullPointerException
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.app.ActivityThread.access$600(ActivityThread.java:141)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.os.Handler.dispatchMessage(Handler.java:99)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.os.Looper.loop(Looper.java:137)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.app.ActivityThread.main(ActivityThread.java:5103)
12-26 02:34:20.240: E/AndroidRuntime(1734): at java.lang.reflect.Method.invokeNative(Native Method)
12-26 02:34:20.240: E/AndroidRuntime(1734): at java.lang.reflect.Method.invoke(Method.java:525)
12-26 02:34:20.240: E/AndroidRuntime(1734): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
12-26 02:34:20.240: E/AndroidRuntime(1734): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-26 02:34:20.240: E/AndroidRuntime(1734): at dalvik.system.NativeStart.main(Native Method)
12-26 02:34:20.240: E/AndroidRuntime(1734): Caused by: java.lang.NullPointerException
12-26 02:34:20.240: E/AndroidRuntime(1734): at com.testing.mypractise.AndroidXMLParsingActivity.onCreate(AndroidXMLParsingActivity.java:55)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.app.Activity.performCreate(Activity.java:5133)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
12-26 02:34:20.240: E/AndroidRuntime(1734): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
12-26 02:34:20.240: E/AndroidRuntime(1734): ... 11 more
AndroidXmlParsingActivity：
public class AndroidXMLParsingActivity extends ListActivity {
// All static variables
static final String URL = "http://....../.../Images/testing.xml";
// XML node keys
static final String KEY_ITEM = "item"; // parent node
static final String KEY_CATEGORY = "category";
static final String KEY_CHANNELNAME = "channelname";
//Intent imgvw;
@Override
public void onCreate(Bundle savedInstanceState) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
super.onCreate(savedInstanceState);
setContentView(R.layout.tv_main);
ArrayList<HashMap<String, String>> channellist = new ArrayList<HashMap<String, String>>();
XMLParser parser = new XMLParser();
String xml = parser.getXmlFromUrl(URL);
Document doc = parser.getDomElement(xml);
**NodeList nl = doc.getElementsByTagName(KEY_ITEM);** => this is 55th line
for (int i = 0; i < nl.getLength(); i++) {
HashMap<String, String> listmap = new HashMap<String, String>();
Element e = (Element) nl.item(i);
listmap.put(KEY_CATEGORY, parser.getValue(e, KEY_CATEGORY));
listmap.put(KEY_CHANNELNAME, parser.getValue(e, KEY_CHANNELNAME));
// adding HashList to ArrayList
channellist.add(listmap);
}
// Adding menuItems to ListView
ListAdapter adapter = new SimpleAdapter(this, channellist,
R.layout.list_item,
new String[] { KEY_CATEGORY, KEY_CHANNELNAME}, new int[] {
R.id.category, R.id.cahnnel_name});
setListAdapter(adapter);
// selecting single ListView item
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String category = ((TextView) view.findViewById(R.id.category)).getText().toString();
String channelname = ((TextView) view.findViewById(R.id.cahnnel_name)).getText().toString();
try {
ImageView imgvw = (ImageView) findViewById (R.id.image_logo);
Bitmap bitmap;
bitmap = BitmapFactory.decodeStream((InputStream)new URL("http://192.168.2.57:8080/Iptvtest/Images/bnews1.png").getContent());
imgvw.setImageBitmap(bitmap);
}
catch (MalformedURLException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
// Starting new intent
Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
in.putExtra(KEY_CATEGORY, category);
in.putExtra(KEY_CHANNELNAME, channelname);
//in.putExtras(imgvw);
startActivity(in);
}
});
}
}
在xmlparser类的getDomElement中遇到此错误：
public class XMLParser {
// constructor
public XMLParser() {
}
/**
* Getting XML from URL making HTTP request
* @param url string
* */
public String getXmlFromUrl(String url) {
String xml = null;
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
xml = EntityUtils.toString(httpEntity);
}
catch (UnsupportedEncodingException e)
{
e.printStackTrace();
}
catch (ClientProtocolException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
// return XML
return xml;
}
/**
* Getting XML DOM element
* @param XML string
* */
public Document getDomElement(String xml){
Document doc = null;
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder db = dbf.newDocumentBuilder();
InputSource is = new InputSource();
is.setCharacterStream(new StringReader(xml)); // error here.
doc = db.parse(is);
}
catch (ParserConfigurationException e)
{
Log.e("Error: ", e.getMessage());
return null;
}
catch (SAXException e)
{
Log.e("Error: ", e.getMessage());
return null;
}
catch (IOException e)
{
Log.e("Error: ", e.getMessage());
return null;
}
return doc;
}
/** Getting node value
* @param elem element
*/
public final String getElementValue( Node elem )
{
Node child;
if( elem != null)
{
if (elem.hasChildNodes())
{
for( child = elem.getFirstChild(); child != null; child = child.getNextSibling() )
{
if( child.getNodeType() == Node.TEXT_NODE )
{
return child.getNodeValue();
}
}
}
}
return "";
}
/**
* Getting node value
* @param Element node
* @param key string
* */
public String getValue(Element item, String str) {
NodeList n = item.getElementsByTagName(str);
return this.getElementValue(n.item(0));
}
}
，错误是
HTTP Error 405 - The HTTP verb used to access this page is not allowed.<br>Internet Information Services (IIS)
答案 0 :(得分：1)
最后我解决了我的空指针异常错误和元读取错误。 而不是HTTPPost我声明HTTPGET。这解决了我的错误。原因是
托管该内容的HTTP应用程序期待其他东西 - 很可能是GET。 Apache HTTP Client有一个类 - HTTPGet ......很自然。至于两者的区别。那么主要区别在于GET方法将参数编码为URL的一部分（例如，您可能会注意到？apiAccessCode = api＆amp; parameter2 = something），而POST将内容作为HTTP消息体的一部分。 HTTP GET也限制为256个字符。用例也是不同的。 HTTP GET应仅用于数据检索，HTTP Post可用于更新内容。
我的代码是
XMLParser:
public String getXmlFromUrl(String url) {
String xml = null;
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpget = new HttpGet (url);
HttpResponse httpResponse = httpClient.execute(httpget); // here i changed my httppost to httpget.
HttpEntity httpEntity = httpResponse.getEntity();
xml = EntityUtils.toString(httpEntity);
}
希望这可能对某人有所帮助： - ）