MainActivity.java

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.example.helloworld.TwitterHelper.ApiException;

import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.inputmethod.InputMethodManager;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
	 static final private int EXIT_ID = Menu.FIRST;

	    private EditText m_search_key;
	    private ImageButton m_btn_ok;
	    private TextView m_header;
	    private ListView m_tweet_list;
	    private InputMethodManager im_ctrl;
	    private JSONArray jresult;

	    /** Called when the activity is first created. */
	    @Override
	    public void onCreate(Bundle savedInstanceState) {
	        super.onCreate(savedInstanceState);

	        /* Use res/layout/main.xml as the view of
	         * this Activity */
	        setContentView(R.layout.activity_main);
	        m_search_key = (EditText) findViewById(R.id.search_key);
	        m_btn_ok = (ImageButton) findViewById(R.id.btn_ok);
	        m_tweet_list = (ListView) findViewById(R.id.tweet_list);
	        m_header = (TextView) findViewById(R.id.tweet_header);
	        m_btn_ok.setOnClickListener(ok_handler);

	        im_ctrl = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
	    }

	    @Override
	    public boolean onCreateOptionsMenu(Menu menu) {
	        super.onCreateOptionsMenu(menu);

	        /* the context menu currently has only one option */
	        menu.add(0, EXIT_ID, 0, R.string.exit);
	        return true;
	    }

	    @Override
	    public boolean onOptionsItemSelected(MenuItem item) {
	        switch (item.getItemId()) {
	        case EXIT_ID:
	            finish(); /* terminate the application */
	            return true;
	        }
	        return super.onOptionsItemSelected(item);
	    }

	    OnClickListener ok_handler = new OnClickListener() {
	        @Override
	        public void onClick(View v) {
	            /* hide the soft keyboard */
	            im_ctrl.hideSoftInputFromWindow(m_search_key.getWindowToken(), 0);

	            new TwitterTask().execute(m_search_key.getText().toString());
	            /* show a brief message */
	            Toast.makeText(getApplicationContext(),
	                    getString(R.string.hello) + " " + m_search_key.getText(),
	                    Toast.LENGTH_LONG).show();
	        }
	    };

	    /* Params (String), Progress (Integer), Result (String) */
	    private class TwitterTask extends AsyncTask<String, Integer, String>
	    {

	        @Override
	        protected String doInBackground(String... params) {
	            String query = params[0];
	            if (query == null) return "";
	            try {
	                String result = TwitterHelper.downloadFromServer(query);
	                return result;
	            } catch (ApiException e) {
	                e.printStackTrace();
	                Log.e("HSD", "Problem making twitter search request");
	                System.out.println("error");
	            }
	            return "";
	        }

	        @Override
	        protected void onPostExecute(String result) {
	            m_tweet_list.setAdapter(new JSONAdapter(getApplicationContext()));
	            try {
	                JSONObject obj = new JSONObject(result);
	                jresult = obj.getJSONArray("results");
	                String info = obj.getString("next_page");
	                m_header.setText(info);
	            } catch (JSONException e) {
	            	System.out.println("error2");
	                e.printStackTrace();
	            }
	        }
	    }

	    /*--- ListAdapter for rendering JSON data ---*/
	    private class JSONAdapter extends BaseAdapter
	    {
	        private Context mCtx;

	        public JSONAdapter (Context c)
	        {
	            mCtx = c;
	        }

	        @Override
	        public int getCount() {
	            return jresult == null ? 0 : jresult.length();
	        }

	        @Override
	        public Object getItem(int arg0) {
	            return null;
	        }

	        @Override
	        public long getItemId(int pos) {
	            return pos;
	        }

	        @Override
	        public View getView(int pos, View convertView, ViewGroup parent) {
	            TextView tv;

	            if (convertView == null)
	                tv = new TextView(mCtx);
	            else
	                tv = (TextView) convertView;
	            try {
	                JSONObject obj = jresult.getJSONObject(pos);
	                tv.setText(obj.getString("from_user") + ": " +
	                        obj.getString("text"));
	            } catch (JSONException e) {
	                tv.setText (e.getMessage());
	            }
	            return tv;
	        }

	    }
	}