Register.java

package edu.vanderbilt.vm.noderegister;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Random;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;

import android.location.Location;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.util.JsonWriter;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

/**
 * <p>
 * A utility app to register Nodes into nodes.json.
 * </p>
 * <p>
 * Preparation for usage: turn on GPS and 3G; Make sure you're outdoor with
 * clear view of the sky; Make sure the phone is not plugged in to your laptop,
 * because it needs access to the SD card.
 * </p>
 * <p>
 * Usage: Tap the left button at the bottom of the screen; You'll get a message
 * showing the filename being used, where the node information will be stored;
 * This filename is randomly generated; Walk to a Point of physical
 * significance; tap on the right button with the label "Register"; You'll get
 * a message showing the Id of the Node you've just registered; Continue until
 * you're done; Tap on the left button again to end the session;
 * </p>
 * <p>
 * Final note: Each registering session will generate a .json file with a
 * randomly generated file name. Use the Python script that I wrote to merge
 * multiple .json files together to make a master list.
 * </p>
 * @author athran
 */
public class Register extends FragmentActivity implements OnClickListener {

    private Button mBtn1;

    private Button mBtn2;

    private static final String MAP = "map";

    private static final String NODES = "/nodes";

    private static final String LAT = "latitude";

    private static final String LNG = "longitude";

    private static final String ID = "id";

    private static final String NEIGH = "neighbors";

    private static final int FIRST_ID = 10000;

    private boolean isRegistering;

    private int mLastId;

    private JsonWriter mJw;

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

        // Setup UI
        mBtn1 = (Button)findViewById(R.id.btn1);
        mBtn1.setText("Toggle");
        mBtn1.setOnClickListener(this);

        mBtn2 = (Button)findViewById(R.id.btn2);
        mBtn2.setText("Register");
        mBtn2.setOnClickListener(this);

        // Setup MapFragment
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();

        ft.add(R.id.map_container, new SupportMapFragment(), MAP);
        ft.commit();

        // Initialization
        isRegistering = false;
        mLastId = FIRST_ID;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_register, menu);
        return true;
    }

    @Override
    public void onResume() {
        super.onResume();

        SupportMapFragment frag = (SupportMapFragment)getSupportFragmentManager()
                .findFragmentByTag(MAP);

        GoogleMap map = frag.getMap();
        map.setMyLocationEnabled(true);
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(36.144782, -86.803231), 16));

        isRegistering = true;
        toggleRegistering();
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {

            case R.id.btn1:
                toggleRegistering();
                return;

            case R.id.btn2:
                registerNode();
                return;

            default:
                return;

        }

    }

    @Override
    public void onPause() {
        super.onPause();
        ((SupportMapFragment)getSupportFragmentManager().findFragmentByTag(MAP)).getMap()
                .setMyLocationEnabled(false);
        isRegistering = true;
        toggleRegistering();
    }

    private void toggleRegistering() {

        if (isRegistering) {
            // close everything
            try {
            	mJw.endArray();
                mJw.close();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (NullPointerException e) {
                e.printStackTrace();
            }

            mBtn1.setText("OFF");
            Toast.makeText(this, "Registering ended" + mLastId, Toast.LENGTH_SHORT).show();
            isRegistering = !isRegistering;

        } else {
            // Generate a random file name
            String path = Environment.getExternalStorageDirectory().getAbsolutePath() + NODES;

            Random rand = new Random();
            path += rand.nextInt(1000000);
            path += ".json";

            Toast.makeText(this, path, Toast.LENGTH_SHORT).show();

            // Setup Json writer
            FileWriter fw = null;
            try {
                fw = new FileWriter(new File(path));

            } catch (IOException e) {
                e.printStackTrace();
            }

            mJw = new JsonWriter(fw);
            mJw.setIndent("   ");
            try {
                mJw.beginArray();

            } catch (IOException e) {
                e.printStackTrace();
            }
            mBtn1.setText("ON");
            isRegistering = !isRegistering;
        }
    }

    private void registerNode() {

        if (isRegistering) {

            Location loc = ((SupportMapFragment)getSupportFragmentManager().findFragmentByTag(MAP))
                    .getMap().getMyLocation();
            try {
                mJw.beginObject();

                mJw.name(ID).value(mLastId);
                mJw.name(LAT).value(loc.getLatitude());
                mJw.name(LNG).value(loc.getLongitude());
                mJw.name(NEIGH);
                mJw.beginArray();
                mJw.endArray();

                mJw.endObject();
                Toast.makeText(this, "Registered: " + mLastId, Toast.LENGTH_SHORT).show();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (NullPointerException e) {
                e.printStackTrace();
                Toast.makeText(this, "I think the MapFragment doesn't have a Location yet",
                        Toast.LENGTH_SHORT).show();
            }

            mLastId++;
        } else {
            Toast.makeText(this, "Please initiate registering first", Toast.LENGTH_SHORT).show();
        }
    }

}