Stop working Error while getting data from url using Jsoup

Question

I am an amateur in android programming. I was using Jsoup for getting html from a website and putting it into a textview but I got error. How can I fix this?

My code:

package com.example.hashtag.asdasd;

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.select.Elements;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    Document siteDoc;
    String a;
    Elements p;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn= (Button) findViewById(R.id.button);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                new siteGetter().execute();
            }
        });
    }

    private class siteGetter extends AsyncTask < Void, Void, String>{

        @Override
        protected String doInBackground(Void... voids) {
            try {
                siteDoc = Jsoup.connect("http://hashtagedu.ir").get();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            return null;
        }
    }

    public void displaydata(){
        p = siteDoc.getElementsByTag("p");
        a=p.text();
        TextView tv= (TextView) findViewById(R.id.textView);
        tv.setText(a);
    }
}

My Errors:

java.lang.RuntimeException: An error occurred while executing doInBackground() at android.os.AsyncTask$3.done(AsyncTask.java:309) at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354) at java.util.concurrent.FutureTask.setException(FutureTask.java:223) at java.util.concurrent.FutureTask.run(FutureTask.java:242) at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588) at java.lang.Thread.run(Thread.java:818) Caused by: java.lang.SecurityException: Permission denied (missing INTERNET permission?) at java.net.InetAddress.lookupHostByName(InetAddress.java:464) at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252) at java.net.InetAddress.getAllByName(InetAddress.java:215) at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29) at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:188) at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:157) at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:100) at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:357) at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:340) at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:330) at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:248) at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:437) at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:114) at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:563) at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:540) at org.jsoup.helper.HttpConnection.execute(HttpConnection.java:227) at org.jsoup.helper.HttpConnection.get(HttpConnection.java:216) at com.example.hashtag.asdasd.MainActivity$siteGetter.doInBackground(MainActivity.java:46) at com.example.hashtag.asdasd.MainActivity$siteGetter.doInBackground(MainActivity.java:39) at android.os.AsyncTask$2.call(AsyncTask.java:295) at java.util.concurrent.FutureTask.run(FutureTask.java:237) at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)  at java.lang.Thread.run(Thread.java:818)  Caused by: android.system.GaiException: android_getaddrinfo failed: EAI_NODATA (No address associated with hostname) at libcore.io.Posix.android_getaddrinfo(Native Method) at libcore.io.ForwardingOs.android_getaddrinfo(ForwardingOs.java:55) at java.net.InetAddress.lookupHostByName(InetAddress.java:451) at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)  at java.net.InetAddress.getAllByName(InetAddress.java:215)  at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)  at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:188)  at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:157)  at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:100)  at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:357)  at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:340)  at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:330)  at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:248)  at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:437)  at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:114)  at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:563)  at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:540)  at org.jsoup.helper.HttpConnection.execute(HttpConnection.java:227)  at org.jsoup.helper.HttpConnection.get(HttpConnection.java:216)  at com.example.hashtag.asdasd.MainActivity$siteGetter.doInBackground(MainActivity.java:46)  at com.example.hashtag.asdasd.MainActivity$siteGetter.doInBackground(MainActivity.java:39)  at android.os.AsyncTask$2.call(AsyncTask.java:295)  at java.util.concurrent.FutureTask.run(FutureTask.java:237)  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)  at java.lang.Thread.run(Thread.java:818)  Caused by: android.system.ErrnoException: android_getaddrinfo failed: EACCES (Permission denied) at libcore.io.Posix.android_getaddrinfo(Native Method)  at libcore.io.ForwardingOs.android_getaddrinfo(ForwardingOs.java:55)  at java.net.InetAddress.lookupHostByName(InetAddress.java:451)  at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)  at java.net.InetAddress.getAllByName(InetAddress.java:215)  at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)  at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:188)  at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:157)  at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:100)  at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:357)  at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:340)  at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:330)  at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:248)  at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:437)  at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:114)  at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:563)  at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:540)  at org.jsoup.helper.HttpConnection.execute(HttpConnection.java:227)  at org.jsoup.helper.HttpConnection.get(HttpConnection.java:216)  at com.example.hashtag.asdasd.MainActivity$siteGetter.doInBackground(MainActivity.java:46)  at com.example.hashtag.asdasd.MainActivity$siteGetter.doInBackground(MainActivity.java:39)  at android.os.AsyncTask$2.call(AsyncTask.java:295)  at java.util.concurrent.FutureTask.run(FutureTask.java:237)  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)  at java.lang.Thread.run(Thread.java:818)

Answer 1

Besides setting up the permission <uses-permission android:name="android.permission.INTERNET" /> you currently don't call displaydata() and if you do so from your background task, you should set up a handler for invoking the changes on the ui thread:

public class MainActivity extends AppCompatActivity {

    Handler uiHandler = new Handler();

    Document siteDoc;
    String a;
    Elements p;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn= (Button) findViewById(R.id.button);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                new siteGetter().execute();
            }
        });

    }

    private class siteGetter extends AsyncTask < Void, Void, String>{

        @Override
        protected String doInBackground(Void... voids) {
            try {
                siteDoc = Jsoup.connect("http://hashtagedu.ir").get();
                displaydata();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            return null;
        }
    }

    public void displaydata(){
        p = siteDoc.getElementsByTag("p");
        a=p.text();

        uiHandler.post(new Runnable() {
            @Override
            public void run() {
                TextView tv= (TextView) findViewById(R.id.textView);
                tv.setText(a);
            }
        });
    }
}

Regarding adding a downloaded image (as asked in removed question) to an ImageView (assuming id is R.id.imageView)

Bitmap bitmap;

public void displaydata(){
    p = siteDoc.getElementsByTag("p");
    a=p.text();
    String imageUrl = siteDoc.select("img").first().attr("abs:src");
    bitmap = BitmapFactory.decodeStream((InputStream)new URL(imageUrl).getContent());
    uiHandler.post(new Runnable() {
        @Override
        public void run() {
            TextView tv= (TextView) findViewById(R.id.textView);
            tv.setText(a);

            ImageView i = (ImageView)findViewById(R.id.imageView);
            i.setImageBitmap(bitmap);
        }
    });
}

Answer 2

You must add internet permission to your manifest.

<uses-permission android:name="android.permission.INTERNET" />