如何解析XML文件使用DOM解析？ [英] How to Parse XML file Using Dom Parsing?
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问题描述
我的问题是我使用DOM解析来解析下面的XML文件，但这个给我NullPointerException异常的错误。
任何帮助，将鸭preciated。
MainActivity.java
公共类MainActivity延伸活动{
@覆盖
公共无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
滚动型mScrView1 =新的滚动型（本）;
/ **创建一个新的布局，以显示视图* /
的LinearLayout布局=新的LinearLayout（本）;
layout.setOrientation（1）;
/ **创建一个新的TextView数组来显示结果* /
TextView的ID [];
TextView中发表[];
TextView的内容[];
TextView的标题[];
TextView的mediacontent [];
TextView的mediathumbnail [];
尝试 {
网址URL =新的URL（
http://gdata.youtube.com/feeds/api/users/estudiosabiertostv/uploads）;
DocumentBuilderFactory的DBF = DocumentBuilderFactory.newInstance（）;
DocumentBuilder的DB = dbf.newDocumentBuilder（）;
文档的文档= db.parse（新的InputSource（url.openStream（）））;
doc.getDocumentElement（）归（）。
节点列表节点列表= doc.getElementsByTagName（输入）;
/ **由ArrayList的大小分配的TextView数组长度* /
ID =新的TextView [nodeList.getLength（）];
出版=新的TextView [nodeList.getLength（）];
内容=新的TextView [nodeList.getLength（）];
标题=新的TextView [nodeList.getLength（）];
mediacontent =新的TextView [nodeList.getLength（）];
mediathumbnail =新的TextView [nodeList.getLength（）];
的for（int i = 0; I＆LT; nodeList.getLength（）;我++）{
节点node = nodeList.item（ⅰ）;
ID [i] =新的TextView（本）;
发表[我] =新的TextView（本）;
内容[我] =新的TextView（本）;
标题[i] =新的TextView（本）;
元素fstElmnt =（元）节点;
节点列表IDLIST = fstElmnt.getElementsByTagName（ID）;
元件idElement =（元件）idList.item（0）;
IDLIST = idElement.getChildNodes（）;
ID [I] .setText（ID是=
+（（节点）idList.item（0））getNodeValue（））。
节点列表publishedList = fstElmnt
.getElementsByTagName（发布）;
元件publishedElement =（元件）publishedList.item（0）;
publishedList = publishedElement.getChildNodes（）;
发表[我] .setText（上发表的=
+（（节点）publishedList.item（0））getNodeValue（））。
节点列表contentList = fstElmnt.getElementsByTagName（内容）;
元素ContentElement的=（元）contentList.item（0）;
contentList = contentElement.getChildNodes（）;
内容[我] .setText（内容=
+（（节点）contentList.item（0））getNodeValue（））。
节点列表titleList = fstElmnt.getElementsByTagName（标题）;
元件titleElement =（元件）titleList.item（0）;
titleList = titleElement.getChildNodes（）;
标题[I] .setText（标题=
+（（节点）titleList.item（0））getNodeValue（））。
节点列表nodeList1 = fstElmnt.getElementsByTagName（媒体：集团）;
的System.out.println（尺寸是： - + nodeList1.getLength（））;
对于（INT J = 0; J＆LT; nodeList1.getLength（）; J ++）{
节点节点1 = nodeList1.item（J）;
mediacontent [J] =新的TextView（本）;
mediathumbnail [J] =新的TextView（本）;
元素secondElmnt =（元）节点1;
节点列表mediacontentList = secondElmnt.getElementsByTagName（媒体：内容）;
元件mediacontentElement =（元件）mediacontentList.item（0）;
mediacontentList = mediacontentElement.getChildNodes（）;
mediacontent [J] .setText（mediacontent是=
+（（节点）mediacontentList.item（0））getNodeValue（））。
layout.addView（mediacontent [J]）;
}
layout.addView（ID [I]）;
layout.addView（公布[I]）;
layout.addView（内容[我]）;
layout.addView（标题[I]）;
}
}赶上（例外五）{
的System.out.println（XML帕兴Excpetion =+ E）;
}
/ **设置布局视图中显示* /
mScrView1.addView（布局）;
的setContentView（mScrView1）;
}
}
解决方案
试试这个：
公共类DomParserSampleActivity延伸活动{
@覆盖
公共无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
滚动型mScrView1 =新的滚动型（本）;
/ **创建一个新的布局，以显示视图* /
的LinearLayout布局=新的LinearLayout（本）;
layout.setOrientation（1）;
/ **创建一个新的TextView数组来显示结果* /
TextView的ID [];
TextView中发表[];
TextView的内容[];
TextView的标题[];
TextView的mediacontent [];
TextView的mediathumbnail [];
尝试 {
网址URL =新的URL（
http://gdata.youtube.com/feeds/api/users/estudiosabiertostv/uploads）;
DocumentBuilderFactory的DBF = DocumentBuilderFactory.newInstance（）;
DocumentBuilder的DB = dbf.newDocumentBuilder（）;
文档的文档= db.parse（新的InputSource（url.openStream（）））;
doc.getDocumentElement（）归（）。
节点列表节点列表= doc.getElementsByTagName（输入）;
/ **由ArrayList的大小分配的TextView数组长度* /
ID =新的TextView [nodeList.getLength（）];
出版=新的TextView [nodeList.getLength（）];
内容=新的TextView [nodeList.getLength（）];
标题=新的TextView [nodeList.getLength（）];
mediacontent =新的TextView [nodeList.getLength（）];
mediathumbnail =新的TextView [nodeList.getLength（）];
的for（int i = 0; I＆LT; nodeList.getLength（）;我++）{
节点node = nodeList.item（ⅰ）;
ID [i] =新的TextView（本）;
发表[我] =新的TextView（本）;
内容[我] =新的TextView（本）;
标题[i] =新的TextView（本）;
元素fstElmnt =（元）节点;
节点列表IDLIST = fstElmnt.getElementsByTagName（ID）;
元件idElement =（元件）idList.item（0）;
IDLIST = idElement.getChildNodes（）;
ID [I] .setText（ID是=
+（（节点）idList.item（0））getNodeValue（））。
Log.v（TAG，ID：+ idList.item（0）.getNodeValue（））;
节点列表publishedList = fstElmnt
.getElementsByTagName（发布）;
元件publishedElement =（元件）publishedList.item（0）;
publishedList = publishedElement.getChildNodes（）;
发表[我] .setText（上发表的=
+（（节点）publishedList.item（0））getNodeValue（））。
Log.v（TAG，发表：+ publishedList.item（0）.getNodeValue（））;
节点列表contentList = fstElmnt.getElementsByTagName（内容）;
元素ContentElement的=（元）contentList.item（0）;
contentList = contentElement.getChildNodes（）;
内容[我] .setText（内容=
+（（节点）contentList.item（0））getNodeValue（））。
Log.v（TAG，内容：+ contentList.item（0）.getNodeValue（））;
节点列表titleList = fstElmnt.getElementsByTagName（标题）;
元件titleElement =（元件）titleList.item（0）;
titleList = titleElement.getChildNodes（）;
标题[I] .setText（标题=
+（（节点）titleList.item（0））getNodeValue（））。
Log.v（TAG，TITULO：+ titleList.item（0）.getNodeValue（））;
节点列表nodeList1 = fstElmnt
.getElementsByTagName（媒体：集团）;
对于（INT J = 0; J＆LT; nodeList1.getLength（）; J ++）{
节点节点1 = nodeList1.item（J）;
mediacontent [J] =新的TextView（本）;
mediathumbnail [J] =新的TextView（本）;
元素secondElmnt =（元）节点1;
节点列表mediacontentList = secondElmnt
.getElementsByTagName（媒体：内容）;
元素mediacontentElement =（元）mediacontentList
.item（0）;
mediacontent [J] .setText（mediacontent网址是=
+ mediacontentElement.getAttribute（URL））;
Log.v（TAG，MEDIACONTENT：+ mediacontentElement.getAttribute（URL））;
节点列表mediathumbnailList = secondElmnt
.getElementsByTagName（媒体：缩略图）;
元素mediathumbnailElement =（元）mediathumbnailList
.item（0）;
mediathumbnail [J] .setText（mediathumbnail网址是=
+ mediathumbnailElement.getAttribute（URL））;
Log.v（TAG，MEDIATHUMBNAIL：+ mediathumbnailElement.getAttribute（URL））;
layout.addView（mediacontent [J]）;
layout.addView（mediathumbnail [J]）;
}
layout.addView（ID [I]）;
layout.addView（公布[I]）;
layout.addView（内容[我]）;
layout.addView（标题[I]）;
}
}赶上（例外五）{
e.printStackTrace（）;
}
/ **设置布局视图中显示* /
mScrView1.addView（布局）;
的setContentView（mScrView1）;
}
}
不要忘了一根线，如果做不到这一点内这样做，用这些线 之后的onCreate（）
StrictMode.ThreadPolicy政策=新StrictMode.ThreadPolicy.Builder（）
.permitAll（）建立（）。
StrictMode.setThreadPolicy（政策）;
My Problem is I am Using Dom Parsing to parse below xml file but this give me error of NullPointerException.
Any Help Would be Appreciated.
MainActivity.java
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ScrollView mScrView1 = new ScrollView(this);
/** Create a new layout to display the view */
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(1);
/** Create a new textview array to display the results */
TextView id[];
TextView published[];
TextView content[];
TextView title[];
TextView mediacontent[];
TextView mediathumbnail[];
try {
URL url = new URL(
"http://gdata.youtube.com/feeds/api/users/estudiosabiertostv/uploads");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new InputSource(url.openStream()));
doc.getDocumentElement().normalize();
NodeList nodeList = doc.getElementsByTagName("entry");
/** Assign textview array length by arraylist size */
id = new TextView[nodeList.getLength()];
published = new TextView[nodeList.getLength()];
content = new TextView[nodeList.getLength()];
title = new TextView[nodeList.getLength()];
mediacontent = new TextView[nodeList.getLength()];
mediathumbnail = new TextView[nodeList.getLength()];
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
id[i] = new TextView(this);
published[i] = new TextView(this);
content[i] = new TextView(this);
title[i] = new TextView(this);
Element fstElmnt = (Element) node;
NodeList idList = fstElmnt.getElementsByTagName("id");
Element idElement = (Element) idList.item(0);
idList = idElement.getChildNodes();
id[i].setText("Id is = "
+ ((Node) idList.item(0)).getNodeValue());
NodeList publishedList = fstElmnt
.getElementsByTagName("published");
Element publishedElement = (Element) publishedList.item(0);
publishedList = publishedElement.getChildNodes();
published[i].setText("published is = "
+ ((Node) publishedList.item(0)).getNodeValue());
NodeList contentList = fstElmnt.getElementsByTagName("content");
Element contentElement = (Element) contentList.item(0);
contentList = contentElement.getChildNodes();
content[i].setText("content is = "
+ ((Node) contentList.item(0)).getNodeValue());
NodeList titleList = fstElmnt.getElementsByTagName("title");
Element titleElement = (Element) titleList.item(0);
titleList = titleElement.getChildNodes();
title[i].setText("title is = "
+ ((Node) titleList.item(0)).getNodeValue());
NodeList nodeList1 = fstElmnt.getElementsByTagName("media:group");
System.out.println("Size is:- " +nodeList1.getLength());
for (int j = 0; j < nodeList1.getLength(); j++) {
Node node1 = nodeList1.item(j);
mediacontent[j] = new TextView(this);
mediathumbnail[j] = new TextView(this);
Element secondElmnt = (Element) node1;
NodeList mediacontentList = secondElmnt.getElementsByTagName("media:content");
Element mediacontentElement = (Element) mediacontentList.item(0);
mediacontentList = mediacontentElement.getChildNodes();
mediacontent[j].setText("mediacontent is = "
+ ((Node) mediacontentList.item(0)).getNodeValue());
layout.addView(mediacontent[j]);
}
layout.addView(id[i]);
layout.addView(published[i]);
layout.addView(content[i]);
layout.addView(title[i]);
}
} catch (Exception e) {
System.out.println("XML Pasing Excpetion = " + e);
}
/** Set the layout view to display */
mScrView1.addView(layout);
setContentView(mScrView1);
}
}
解决方案
Try this:
public class DomParserSampleActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ScrollView mScrView1 = new ScrollView(this);
/** Create a new layout to display the view */
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(1);
/** Create a new textview array to display the results */
TextView id[];
TextView published[];
TextView content[];
TextView title[];
TextView mediacontent[];
TextView mediathumbnail[];
try {
URL url = new URL(
"http://gdata.youtube.com/feeds/api/users/estudiosabiertostv/uploads");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new InputSource(url.openStream()));
doc.getDocumentElement().normalize();
NodeList nodeList = doc.getElementsByTagName("entry");
/** Assign textview array length by arraylist size */
id = new TextView[nodeList.getLength()];
published = new TextView[nodeList.getLength()];
content = new TextView[nodeList.getLength()];
title = new TextView[nodeList.getLength()];
mediacontent = new TextView[nodeList.getLength()];
mediathumbnail = new TextView[nodeList.getLength()];
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
id[i] = new TextView(this);
published[i] = new TextView(this);
content[i] = new TextView(this);
title[i] = new TextView(this);
Element fstElmnt = (Element) node;
NodeList idList = fstElmnt.getElementsByTagName("id");
Element idElement = (Element) idList.item(0);
idList = idElement.getChildNodes();
id[i].setText("Id is = "
+ ((Node) idList.item(0)).getNodeValue());
Log.v("TAG","id: "+idList.item(0).getNodeValue());
NodeList publishedList = fstElmnt
.getElementsByTagName("published");
Element publishedElement = (Element) publishedList.item(0);
publishedList = publishedElement.getChildNodes();
published[i].setText("published is = "
+ ((Node) publishedList.item(0)).getNodeValue());
Log.v("TAG","published: "+publishedList.item(0).getNodeValue());
NodeList contentList = fstElmnt.getElementsByTagName("content");
Element contentElement = (Element) contentList.item(0);
contentList = contentElement.getChildNodes();
content[i].setText("content is = "
+ ((Node) contentList.item(0)).getNodeValue());
Log.v("TAG","content: "+contentList.item(0).getNodeValue());
NodeList titleList = fstElmnt.getElementsByTagName("title");
Element titleElement = (Element) titleList.item(0);
titleList = titleElement.getChildNodes();
title[i].setText("title is = "
+ ((Node) titleList.item(0)).getNodeValue());
Log.v("TAG","titulo: "+titleList.item(0).getNodeValue());
NodeList nodeList1 = fstElmnt
.getElementsByTagName("media:group");
for (int j = 0; j < nodeList1.getLength(); j++) {
Node node1 = nodeList1.item(j);
mediacontent[j] = new TextView(this);
mediathumbnail[j] = new TextView(this);
Element secondElmnt = (Element) node1;
NodeList mediacontentList = secondElmnt
.getElementsByTagName("media:content");
Element mediacontentElement = (Element) mediacontentList
.item(0);
mediacontent[j].setText("mediacontent url is = "
+ mediacontentElement.getAttribute("url"));
Log.v("TAG","MEDIACONTENT: "+mediacontentElement.getAttribute("url"));
NodeList mediathumbnailList = secondElmnt
.getElementsByTagName("media:thumbnail");
Element mediathumbnailElement = (Element) mediathumbnailList
.item(0);
mediathumbnail[j].setText("mediathumbnail url is = "
+ mediathumbnailElement.getAttribute("url"));
Log.v("TAG","MEDIATHUMBNAIL: "+mediathumbnailElement.getAttribute("url"));
layout.addView(mediacontent[j]);
layout.addView(mediathumbnail[j]);
}
layout.addView(id[i]);
layout.addView(published[i]);
layout.addView(content[i]);
layout.addView(title[i]);
}
} catch (Exception e) {
e.printStackTrace();
}
/** Set the layout view to display */
mScrView1.addView(layout);
setContentView(mScrView1);
}
}
Do not forget to do so within a thread or failing that, use these lines After the onCreate()
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
这篇关于如何解析XML文件使用DOM解析？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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