我想开始我的异步任务：
package com.androidhive.xmlparsing;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.NameValuePair;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.params.ConnManagerParams;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import android.app.Notification;
import android.app.NotificationManager;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
public class onoff extends AsyncTask<String, Void, String> {
private static final int REGISTRATION_TIMEOUT = 3 * 1000;
private static final int WAIT_TIMEOUT = 30 * 1000;
private final HttpClient httpclient = new DefaultHttpClient();
final HttpParams params = httpclient.getParams();
HttpResponse response;
private String content = null;
private boolean error = false;
private Context mContext;
private int NOTIFICATION_ID = 1;
private Notification mNotification;
private NotificationManager mNotificationManager;
public onoff(Context context){
this.mContext = context;
//Get the notification manager
mNotificationManager = (NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);
}
protected void onPreExecute() {
createNotification("Data download is in progress","");
}
protected String doInBackground(String... urls) {
String URL = null;
String param1 = null;
String param2 = null;
String param3 = null;
try {
//URL passed to the AsyncTask
URL = urls[0];
param1 = urls[1];
param2 = urls[2];
param3 = urls[3];
HttpConnectionParams.setConnectionTimeout(params, REGISTRATION_TIMEOUT);
HttpConnectionParams.setSoTimeout(params, WAIT_TIMEOUT);
ConnManagerParams.setTimeout(params, WAIT_TIMEOUT);
HttpPost httpPost = new HttpPost(URL);
//Any other parameters you would like to set
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(3);
nameValuePairs.add(new BasicNameValuePair("token",param1));
nameValuePairs.add(new BasicNameValuePair("deviceid",param2));
nameValuePairs.add(new BasicNameValuePair("actionid",param3));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
//Response from the Http Request
response = httpclient.execute(httpPost);
StatusLine statusLine = response.getStatusLine();
//Check the Http Request for success
if(statusLine.getStatusCode() == HttpStatus.SC_OK){
ByteArrayOutputStream out = new ByteArrayOutputStream();
response.getEntity().writeTo(out);
out.close();
content = out.toString();
Log.d("test", content);
}
else{
//Closes the connection.
Log.w("HTTP1:",statusLine.getReasonPhrase());
response.getEntity().getContent().close();
throw new IOException(statusLine.getReasonPhrase());
}
} catch (ClientProtocolException e) {
Log.w("HTTP2:",e );
content = e.getMessage();
error = true;
cancel(true);
} catch (IOException e) {
Log.w("HTTP3:",e );
content = e.getMessage();
error = true;
cancel(true);
}catch (Exception e) {
Log.w("HTTP4:",e );
content = e.getMessage();
error = true;
cancel(true);
}
return content;
}
protected void onCancelled() {
createNotification("Es ist ein Problem aufgetreten(2)!",content);
}
protected void onPostExecute(String content) {
if (error) {
createNotification("Es ist ein Problem aufgetreten(1)!",content);
} else {
createNotification("Gerät erfolgreich geschaltet(3)!","");
}
}
private void createNotification(String contentTitle, String contentText) {
//Build the notification using Notification.Builder
Notification.Builder builder = new Notification.Builder(mContext)
.setSmallIcon(android.R.drawable.stat_sys_download)
.setAutoCancel(true)
.setContentTitle(contentTitle)
.setContentText(contentText);
//Get current notification
mNotification = builder.getNotification();
//Show the notification
mNotificationManager.notify(NOTIFICATION_ID, mNotification);
}
}
在 ListActivity 的 onclicklistener 中：
package com.androidhive.xmlparsing;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class SingleMenuItemActivity extends Activity {
// XML node keys
static final String KEY_NAME = "name";
static final String KEY_COST = "cost";
static final String KEY_DESC = "description";
static final String KEY_ID = "deviceid";
static final String KEY_texton = "texton";
static final String KEY_textoff = "textoff";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.single_list_item);
// getting intent data
Intent in = getIntent();
// Get XML values from previous intent
String name = in.getStringExtra(KEY_NAME);
String cost = in.getStringExtra(KEY_COST);
String description = in.getStringExtra(KEY_DESC);
String deviceid = in.getStringExtra(KEY_ID);
String on = in.getStringExtra(KEY_texton);
String off = in.getStringExtra(KEY_textoff);
// Displaying all values on the screen
TextView lblName = (TextView) findViewById(R.id.name_label);
TextView lblCost = (TextView) findViewById(R.id.cost_label);
TextView lblDesc = (TextView) findViewById(R.id.description_label);
TextView lblid = (TextView) findViewById(R.id.id_label);
// TextView lblon = (Button) findViewById(R.id.on);
// TextView lbloff = (Button) findViewById(R.id.off);
Button lblon = (Button)findViewById(R.id.on);
lblon.getText().toString();
lblon.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String[] url={"http://url.de/", "url","/" + KEY_ID,"/" + KEY_COST};
new onoff(this).execute(url);
}
});
Button lbloff = (Button)findViewById(R.id.off);
lbloff.getText().toString();
lbloff.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
}
});
lblName.setText(name);
lblCost.setText(cost);
lblDesc.setText(description);
lblid.setText(deviceid);
lblon.setText(on);
lbloff.setText(off);
}
}
xml解析器：
package com.androidhive.xmlparsing;
import java.io.IOException;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import android.util.Log;
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));
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));
}
}
但我在 onoff（这个）时出错了？构造函数 onoff 未定义我想在单击按钮时启动 http 请求。有人能帮我吗？