THE INTERFACE

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="computervision.grewe.httpassynctask.MainActivity"> <TextView android:id="@+id/textDump" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="data to appear here" /> </RelativeLayout>

THE MANIFEST FILE

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="computervision.grewe.httpassynctask">

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

THE CODE

package computervision.grewe.httpassynctask;

import android.app.Activity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;

import android.app.Activity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;



public class MainActivity extends AppCompatActivity {

    TextView dumpText;

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

        //grab TextView
        dumpText = (TextView) findViewById(R.id.textDump);
        //grab data from Yelp only if we have connectivity
        ConnectivityManager connMgr = (ConnectivityManager)
                getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        if (networkInfo != null && networkInfo.isConnected()) {
            // fetch data
            getYelpdata();
        } else {
            // display error
            dumpText.setText("No Connection");
        }
    }

    //go to yelp api rest URL and grab data --initially no OAuth
    protected void getYelpdata() {
        //call ASync Task class to process getting data
        //String stringUrl = "http://api.yelp.com/v2/search?term=food&location=San+Francisco";
        String stringUrl = "https://www.yelp.com/san-jose";

        new DownloadWebpageTask().execute(stringUrl);

    }


    @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
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.textDump) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }



    //private class to do ASYNC getting of yelp data
    // Uses AsyncTask to create a task away from the main UI thread. This task takes a
    // URL string and uses it to create an HttpUrlConnection. Once the connection
    // has been established, the AsyncTask downloads the contents of the webpage as
    // an InputStream. Finally, the InputStream is converted into a string, which is
    // displayed in the UI by the AsyncTask's onPostExecute method.
    private class DownloadWebpageTask extends AsyncTask<String, Void, String> {
        @Override
        protected String doInBackground(String... urls) {

            // params comes from the execute() call: params[0] is the url.
            try {
                return downloadUrl(urls[0]);
            } catch (IOException e) {
                return "Unable to retrieve web page. URL may be invalid.";
            }
        }
        // onPostExecute displays the results of the AsyncTask.
        @Override
        protected void onPostExecute(String result) {
            dumpText.setText(result);
        }

        //this is the workhorse method that does the HTTPRequest
        // Given a URL, establishes an HttpUrlConnection and retrieves
        // the web page content as a InputStream, which it returns as
        // a string.
        private String downloadUrl(String myurl) throws IOException {
            InputStream is = null;
            // Only display the first 500 characters of the retrieved
            // web page content.
            int len = 500;

            try {
                URL url = new URL(myurl);
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setReadTimeout(10000 /* milliseconds */);
                conn.setConnectTimeout(15000 /* milliseconds */);
                conn.setRequestMethod("GET");
                conn.setDoInput(true);
                // Starts the query
                conn.connect();
                int response = conn.getResponseCode();
                Log.d("ASyncTask", "The response is: " + response);
                is = conn.getInputStream();

                // Convert the InputStream into a string
                String contentAsString = readIt(is, len);
                return contentAsString;

                // Makes sure that the InputStream is closed after the app is
                // finished using it.
            } finally {
                if (is != null) {
                    is.close();
                }
            }
        }

        // Reads an InputStream and converts it to a String.
        public String readIt(InputStream stream, int len) throws IOException, UnsupportedEncodingException {
            Reader reader = null;
            reader = new InputStreamReader(stream, "UTF-8");
            char[] buffer = new char[len];
            reader.read(buffer);
            return new String(buffer);
        }


    }


}