Develop Reference

How to parse data from a website using Jsoup in android

I am developing an application in which I want some data from a website to display in activity. For this I'm using Jsoup to parse data. But I am getting error at:
org.jsoup.nodes.Document document = Jsoup.connect(url).get();
Here it is my complete code below, I am not getting any idea about what is wrong I'm doing...
import java.io.IOException;
import org.jsoup.Jsoup;
import org.jsoup.select.Elements;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.DocumentsContract.Document;
import android.app.Activity;
import android.view.Menu;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.TextView;
public class Events extends Activity
{
//WebView web1;
TextView t1;
String url="https://sites.google.com/site/holyfamilychurchpestomsagar/notices-for-the-week";
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_events);
t1=(TextView)findViewById(R.id.textView1);
Title t2=new Title();
t2.execute();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.events, menu);
return true;
}
private class Title extends AsyncTask<Void, Void, Void> {
Elements title;
String desc;
#Override
protected void onPreExecute()
{
super.onPreExecute();
}
#Override
protected Void doInBackground(Void... params) {
try {
// Connect to the web site
org.jsoup.nodes.Document document = Jsoup.connect(url).get();
// Get the html document title
title = document.select("meta[name=title]");
desc = title.attr("content");
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result)
{
// Set title into TextView
t1.setText(desc);
}
}
}

Is the device online? Ok, im sure you thought of that ;-) Are you
sure its exactly this line? Are you running in your catch clause, or
does the app crash?
You should always add a null pointer check when working with jsoup,
because when the selecting process is unsuccessful, the method will
return null!
Can you post your stacktrace?
Ok when the app crashes then Im pretty shure its not the connection itself but one of the lines below. Add a check for null pointers, or add a catch clause.

Jsoup parsing with Android

I'm trying to parse html with Jsoup lib. However, I did not get what I want.
I want to bring to the screen of a mobile device the entire text of the tag <pre>
Please tell me, how do I get the text from web? How do I need to fix?
Web site: http://devanswers.ru/text.php
package com.example.devanswers;
import java.io.IOException;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.TextView;
public class MainActivity extends Activity {
TextView DevMainText;
ImageView DevMainImage;
MyTask DevMain;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DevMainText = (TextView) findViewById(R.id.DevMainText);
DevMainImage = (ImageView) findViewById(R.id.DevMainImage);
OnClickListener onClick = new OnClickListener() {
public void onClick(View v) {
DevMain = new MyTask();
DevMain.execute();
}
};
DevMainImage.setOnClickListener(onClick);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
class MyTask extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
DevMainImage.setEnabled(false);
}
#Override
protected Void doInBackground(Void... params) {
Document doc;
try {
doc = Jsoup.connect("http://devanswers.ru/text.php").get();
Elements links = doc.getElementsByTag("pre");
for (Element link : links) {
DevMainText.setText((link.text()));
}
} catch (IOException e) {
// TODO Auto-generated catch block
DevMainText.setText("Error");
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
DevMainImage.setEnabled(true);
}
}
}

I have never use the Jsoup before but what i can see from your code that you over write what in the DevMainText each time you get data from the page
so you should setText in your textview like this:
String maintext = "";
for (Element link : links) {
maintext += link.text() +"\n";
}
DevMainText.setText(maintext);

Infact the response is not wrapped in the <pre> tag. Its the browser who wraps the raw response in the <pre> tag when you view the source.
Instead of doc.getElementsByTag("pre") try doc.getElementsByTag("body")

You could also try using the Android WebView component, if you want to display the entire page.
http://developer.android.com/reference/android/webkit/WebView.html
You can easily parse the page using the URI class Uri uri = Uri.parse("http://devanswers.ru/text.php");and then display this in a WebView.

threads to AsyncTask( android, Modbus/TCP)

I'm working a connection to a PLC via TCP / Modbus and Jamod library, therefore I use and work with threads. I'm using to handle AsyncTask thread function, but when running my code the application is not responding and closes automatically. Thanks for the help in advance =)
package com.JR.scada;
import java.net.InetAddress;
import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.io.ModbusTCPTransaction;
import net.wimpi.modbus.msg.ReadInputDiscretesRequest;
import net.wimpi.modbus.msg.ReadInputDiscretesResponse;
import net.wimpi.modbus.net.TCPMasterConnection;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Main extends Activity{
TextView text, depurar;
EditText IP;
Button boton;
TCPMasterConnection con = null; //the TCP connection
ModbusTCPTransaction trans = null; //the Modbus transaction
InetAddress addr = null; //direccion del esclavo
int port = Modbus.DEFAULT_PORT;//puerto por defecto 502
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text = (TextView) findViewById(R.id.lblRegistro);
IP = (EditText) findViewById(R.id.txtIp);
depurar = (TextView) findViewById(R.id.txtdepurar);
boton = (Button)findViewById(R.id.btnVerRegistro);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
protected void onStop() {
super.onStop();
//Close the TCP connection
con.close();
}
public class conectar extends AsyncTask<String,String,Integer>{
protected Integer doInBackground(String... urls) {
try {
text.setText("Entro en el try");
//IP address;
addr = InetAddress.getByName("212.170.50.238");
// Open the connection
con = new TCPMasterConnection(addr);
con.setPort(port);
con.connect ();
} catch (Exception e) {
Log.d("MODBUS","connection error", e);
depurar.setText("no conecta");
return 1;
}
return 0;
}
protected void onPostExecute(Integer bytes) {
depurar.setText("conecta");
}
}
public void onClick(View v) {
conectar conectamos = new conectar();
conectamos.execute("hola");
}
see any errors?

We can't touch UI during onBackground()
depurar.setText("no conecta");
Use UI thread or put it on onPost().

global functions accessing system features android

hi i have created a global actions class and created functions inside this class which i'm trying to access inside another activity the problem i'm having is that in eclipse I'm getting coding errors around the functions that access system feature such as getSystemService() and getApplicationContext() does anyone know why or how to let a global class accept system features?
heres what i have so far heres my GloblActions.java
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;
public class GlobalActions{
Context mContext;
// constructor
public GlobalActions(Context context){
this.mContext = context;
}
public final static boolean isOnline (Context someContext){ {
Log.v("globals", "isonline");
ConnectivityManager cm = (ConnectivityManager) someContext.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting()) {
return true;
}
return false;
}
}
public final static void checkInternet(Context someContext){
isOnline(someContext);
if(isOnline(someContext) == false){
Log.v("globals", "isOnline = false");
Intent register = new Intent(someContext.getApplicationContext(), LoginForm.class);
someContext.startActivity(register);
}
}
}
heres where i'm using the function in an activity. my goal is is to check internet connection on every activity by just calling the global function and if no connection is found go to an activity that says no internet connection.
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.content.Intent;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.TextView;
import android.os.Handler;
import com.myApp.myApp.GlobalActions;
public class IntroLoader extends Activity {
public Handler handler;
public TextView loadText = null;
public Animation AniFadein = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.lo_introloader);
findViewById(R.id.progressBar1).setVisibility(View.GONE);
findViewById(R.id.loadTextView).setVisibility(View.GONE);
GlobalActions.isOnline(null);
GlobalActions.checkInternet(null);
handler = new Handler();
final Runnable fadeIn = new Runnable()
{
public void run()
{
animations();
findViewById(R.id.progressBar1).setVisibility(View.VISIBLE);
findViewById(R.id.loadTextView).setVisibility(View.VISIBLE);
}
};
handler.postDelayed(fadeIn, 3000);
final Runnable aSyncTask= new Runnable()
{
public void run()
{
PostTask posttask;
posttask = new PostTask();
posttask.execute();
}
};
handler.postDelayed(aSyncTask, 4000);
}
public void animations(){
loadText = (TextView)findViewById(R.id.loadTextView);
AniFadein = AnimationUtils.loadAnimation(this, R.anim.fadein);
loadText.startAnimation(AniFadein);
}
public class PostTask extends AsyncTask<Void, String, Boolean> {
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected Boolean doInBackground(Void... params) {
boolean result = false;
publishProgress("progress");
return result;
}
protected void onProgressUpdate(String... progress) {
StringBuilder str = new StringBuilder();
for (int i = 1; i < progress.length; i++) {
str.append(progress[i] + " ");
}
}
#Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
checkLoginData();
}
}
public void checkLoginData(){
Intent register = new Intent(getApplicationContext(), LoginForm.class);
startActivity(register);
}
}

Do
ConnectivityManager cm = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
Contexts can use the method getSystemService() but your class isn't a Context, you need to use your mContext variable.
This means that you can also replace getApplicationContext() with mContext. And if you really need getApplicationContext() (unlikely - normal Contexts should work fine), use
mContext.getApplicationContext()
Also, you declare your isOnline() method as static, but then you need to use a Context for checking and making the toast. Either don't make it static or change it so it accepts in a Context, eg
public final static boolean isOnline (Context someContext){
And replace calls there that need a Context with someContext. Static methods don't need an instance of the class, and so, you can't use mContext. Once you fix the getApplicationContext() issue you have now, the compiler should throw an error about accessing a non static field in a static way. Same with your checkInternet(). I suggest you revaluate your logic, there are multiple problems with your class - I suggest making everything a static method that accepts in a Context which will be given by the calling Activity.
Lastly be careful about showing Toasts and other UI Elements in a global non-ui class. Toasts should be fine since they run on top of windows, but a Dialog will need a window, and if mContext is not an instance of Activity, that will fail (Activities have a window, other Contexts (like getApplicationContext()), do not.

HTMLcleaner in AsyncTask

I am trying to get HTML cleaner to parse the info from a website and then use Xpath to find the data I'm looking for. I have the htmlcleaner stuff in a separate AsyncTask class and the app seems to work on my phone. However, when I push the button nothing happens. Here is my main activity class and my AsyncTask Class.
package ru.habrahabr.stackparser;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.htmlcleaner.TagNode;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.*;
public class stackParser extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button) findViewById(R.id.parse);
button.setOnClickListener(myListener);
}
private OnClickListener myListener = new OnClickListener() {
public void onClick(View v) {
new parseSite().execute("http://xjaphx.wordpress.com/");
}
};
private class parseSite extends AsyncTask<String, Void, String> {
protected String doInBackground(String... arg) {
String output = new String();
try {
htmlHelper hh = new htmlHelper();
} finally {
}
return output;
}
protected void onPostExecute(String output) {
TextView view = (TextView) findViewById(R.id.tv1);
view.setText((CharSequence) output);
}
}
}
And here's my referenced class. I'd really appreciate it if someone could look at this and tell me what's up. I tried to follow a working example and put my own Url and Xpath in but it's not working.
package ru.habrahabr.stackparser;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import org.htmlcleaner.HtmlCleaner;
import org.htmlcleaner.TagNode;
import org.htmlcleaner.XPatherException;
public class htmlHelper {
TagNode rootNode;
String stats;
static final String XPATH_STATS = "//div[#id='blog-stats']/ul/li";
public String htmlHelper(URL htmlPage) throws IOException, XPatherException {
HtmlCleaner cleaner = new HtmlCleaner();
rootNode = cleaner.clean(htmlPage);
// query XPath
Object[] statsNode = rootNode.evaluateXPath(XPATH_STATS);
// process data if found any node
if (statsNode.length > 0) {
TagNode resultNode = (TagNode) statsNode[0];
stats = resultNode.getText().toString();
}
return stats;
}
}

Change AsyncTask doInBackground method as :
#Override
protected String doInBackground(String... arg) {
String output "";
try {
htmlHelper hh = new htmlHelper();
output=hh.htmlHelper(arg[0]); //<< call htmlHelper method here
} finally {
}
return output;
}
because you are currently only creating an instance of htmlHelper class not calling htmlHelper method from htmlHelper class to get data from web url

Look , I will not care of the data is downloaded or not , but I will assume that the data is already downloaded and besides in the variable output , you just need to place this code inside onPostExecute
runOnUiThread(new Runnable() {
public void run() {
// update data into TextView.
TextView view = (TextView) findViewById(R.id.tv1);
view.setText((CharSequence) output);
}
});
because , sometimes the data is already downloaded but needed to be assigned into Textview or whatever view by using UIthread. Hope this works for you