[英]How do parse xml in android using SAX Parser?
我是android的菜鳥,我正在嘗試學習如何使用SAX解析器解析xml。 我已經編寫了一個測試應用程序來嘗試實現它,但是我似乎無法使其工作。 我希望我的textview顯示來自xml的相應值,但是它不起作用。 有人可以幫忙嗎?
解析器
public class ParseTestActivity extends Activity implements View.OnClickListener {
/** Called when the activity is first created. */
final static String TAG = "spotxml";
TextView tv;
WebView xml;
Button help, help2;
int livespot = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tv = (TextView) findViewById(R.id.textView1parsed);
help = (Button) findViewById(R.id.button1);
help2 = (Button) findViewById(R.id.button2);
help.setOnClickListener(this);
help2.setOnClickListener(this);
xml = (WebView) findViewById(R.id.webView1);
try{
xml.loadUrl("http://www.xmlcharts.com/cache/precious-metals.xml");
}catch (Exception e){
e.printStackTrace();
}
try{
URL xmlcharts = new URL("http://www.xmlcharts.com/cache/precious-metals.xml");
//InputSource local = new InputSource(getResources().openRawResource(R.raw.preciousmetals));
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
HandlingXMLStuff doingWork = new HandlingXMLStuff();
xr.setContentHandler(doingWork);
xr.parse(new InputSource(xmlcharts.openStream()));
//xr.parse(local);
XMLDataCollected information = doingWork.getInformation();
//String information = doingWork.getInformation();
tv.setText(information.toString());
livespot = Integer.parseInt(information.toString());
}catch(Exception e){
Toast.makeText(ParseTestActivity.this, "Error", Toast.LENGTH_LONG).show();
Log.e(TAG, "WeatherQueryError", e);
}
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch(v.getId()){
case R.id.button1:
try{
URL xmlcharts = new URL("http://www.xmlcharts.com/cache/precious-metals.xml");
//InputSource local = new InputSource(getResources().openRawResource(R.raw.preciousmetals));
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
HandlingXMLStuff doingWork = new HandlingXMLStuff();
xr.setContentHandler(doingWork);
xr.parse(new InputSource(xmlcharts.openStream()));
//xr.parse(local);
XMLDataCollected information = doingWork.getInformation();
//String information = doingWork.getInformation();
tv.setText(information.toString());
livespot = Integer.parseInt(information.toString());
}catch(Exception e){
Toast.makeText(ParseTestActivity.this, "Error", Toast.LENGTH_LONG).show();
Log.e(TAG, "WeatherQueryError", e);
}
break;
case R.id.button2:
try{
//URL xmlcharts = new URL("http://www.xmlcharts.com/cache/precious-metals.xml");
InputSource local = new InputSource(getResources().openRawResource(R.raw.preciousmetals));
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
HandlingXMLStuff doingWork = new HandlingXMLStuff();
xr.setContentHandler(doingWork);
//xr.parse(new InputSource(xmlcharts.openStream()));
xr.parse(local);
XMLDataCollected information = doingWork.getInformation();
//String information = doingWork.getInformation();
tv.setText(information.toString());
livespot = Integer.parseInt(information.toString());
}catch(Exception e){
Toast.makeText(ParseTestActivity.this, "Error", Toast.LENGTH_LONG).show();
Log.e(TAG, "WeatherQueryError", e);
}
break;
}
}}
內容處理程序
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class HandlingXMLStuff extends DefaultHandler {
private boolean in_prices = false;
private boolean in_pricelist = false;
private boolean in_uspricegold = false;
private boolean in_uspricesilver = false;
String gs = null;
String ss = null;
private XMLDataCollected info = new XMLDataCollected();
//public String getInformation(){
// return info.datatoString();
//}
public XMLDataCollected getInformation(){
return this.info;
}
@Override
public void startDocument() throws SAXException {
this.info = new XMLDataCollected();
}
@Override
public void endDocument() throws SAXException {
// Nothing to do
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
// TODO Auto-generated method stub
if (localName.equalsIgnoreCase("prices")) {
this.in_prices = true ;
}else if (localName.equalsIgnoreCase("pricelist")) {
String attrValue = attributes.getValue("currency");
if (attrValue.equalsIgnoreCase("usd")){
this.in_pricelist = true;
}else if (localName.equalsIgnoreCase("price")){
String attrValue2 = attributes.getValue("commodity");
if (attrValue2.equalsIgnoreCase("gold")){
this.in_uspricegold = true;
}else if (localName.equalsIgnoreCase("price")){
String attrValue3 = attributes.getValue("commodity");
if (attrValue3.equalsIgnoreCase("silver")){
this.in_uspricesilver = true;
}
}}}
}
@Override
public void endElement(String namespaceURI, String localName, String qName)
throws SAXException {
if (localName.equalsIgnoreCase("prices")) {
this.in_prices = false;
}else if (localName.equalsIgnoreCase("pricelist")) {
this.in_pricelist = false;
}else if (localName.equalsIgnoreCase("price")) {
this.in_uspricegold = false;
}else if (localName.equalsIgnoreCase("price")) {
this.in_uspricesilver = false;
}
}
@Override
public void characters(char[] ch, int start, int length)throws SAXException {
if(this.in_uspricegold) {
//info.setSpotGold(new String (ch, start, length));
//}
int spotgold = Integer.parseInt(new String (ch, start, length));
info.setSpotGold(spotgold);
this.in_uspricegold = false;
}else{}
if(this.in_uspricesilver){
//info.setSpotSilver(new String(ch, start, length));
// }
int spotsilver = Integer.parseInt(new String(ch, start, length));
info.setSpotSilver(spotsilver);
this.in_uspricesilver = false;
}else{}
}
}
收集的數據集
public class XMLDataCollected{
private int spotsilver = 0;
private int spotgold = 0;
public int getSpotGold() {
return spotgold;
}
public void setSpotGold(int spotgold){
this.spotgold = spotgold;
}
public int getSpotSilver() {
return spotsilver;
}
public void setSpotSilver(int spotsilver){
this.spotsilver = spotsilver;
}
public String toString(){
return "gold " + spotgold + " silver "+ spotsilver;
}
}
首先,您的方法字符必須簡單得多。 唯一要做的就是讀取標簽之間的字符。 它將是這樣的:
public void characters(char[] ch, int start, int end) {
buffer.append(new String(ch, start, end));
}
如您所見,我將StringBuffer用作私有字段。 它在startElement方法的開頭實例化,並在endElement的開頭“重置”。
value = buffer.toString();
buffer.setLength(0);
字段值實際上將保留字段的實際值。
我全班供參考:
private String value;
private StringBuffer buffer;
@Override
public void startElement(
String nameSpaceURI,
String localName,
String qName,
Attributes atts
) {
buffer = new StringBuffer();
if(localName.equals("myTag"))
bean = new Bean();
}
public void endElement(
String uri,
String localName,
String qName) {
value = buffer.toString();
buffer.setLength(0);
if(localName.equals("myTag") {
bean.setSomething(value);
}
}
public void characters(char[] ch, int start, int end) {
buffer.append(new String(ch, start, end));
}
希望這可以幫助。 :)
編輯
這里的代碼適用於op xml。 我沒有嘗試過,但應該可以。 ;)
private String value;
private StringBuffer buffer;
private XMLCOllected info;
private boolean inPriceList;
private boolean inGold;
private boolean inSilver;
@Override
public void startElement(
String nameSpaceURI,
String localName,
String qName,
Attributes atts
) {
buffer = new StringBuffer();
if(localName.equals("prices")) {
this.info = new XMLCollected();
} else if(localName.equals("pricelist")) {
String attr = atts.getValue("currency");
if(attr.equals("usd")) {
this.inPriceList = true;
}
} else if(localName.equals("price") && inPrices) {
String attr = atts.getValue("commodity");
if(attr.equals("gold")) {
this.inGold = true;
} else if(attr.equals("silver")) {
this.inSilver = true;
}
}
}
public void endElement(
String uri,
String localName,
String qName) {
value = buffer.toString();
buffer.setLength(0);
if(localName.equals("price") && inGold && inPriceList) {
this.info.setSpotGold(value);
this.inGold = false;
} else if(localName.equals("price") && inSilver && inPriceList) {
this.info.setSpotSilver(value);
this.inSilver = false;
} else if(localName.equals("pricelist")) {
this.inPriceList = false;
}
}
public void characters(char[] ch, int start, int end) {
buffer.append(new String(ch, start, end));
}
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