Belajar Android Direction GoogleMap JSON

Belajar android lagi belajar android lagi, bosan ah yang lain dong. Tapi yang namanya belajar itu tidak boleh bosan. Sebetulnya bosan atau tidak itu relatif.

kalau kita sudah mau sidang, ternyata program yang kita siapkan tiba-tiba ada bagian yang tidak jalan. Contohnya saja yang program atau aplikasi androidnya ada yang menggunakan direction yang menggunakan kml, sejak tanggal 27 Juli 2012 sudah tidak disupport google. Tentu kita akan semangat 45 cari digoogle, tanya ke orang untuk alternatifnya. Ada beberapa email, serta komentar yang menanyakan masalah ini. Akhirnya saya ikut penasaran juga deh untuk cari solusinya, akhirnya ketemu petunjuk berharga dari stackoverflow. Yah harus diakui stackoverflow sangat membantu kita dalam mencari solusi terkait dengan pemrograman.

Sekarang mari kita implementasikan solusi tersebut kedalam project.

1 . Buat project dengan nama AndroidDirectionJSON

2. Edit file main.xml lalu ketikkan kode berikut

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <com.google.android.maps.MapView
        android:id="@+id/mapView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:enabled="true"
        android:clickable="true"
        android:apiKey="0bvY2ipiUvzSE4ybKkHjanqDBGKckFswnJuPw7A"
        />
</RelativeLayout>

3. Buat interface baru dengan nama Parser.java lalu ketikan kode berikut

package com.agusharyanto.net.map.direction.json;

public interface Parser {
	public Route parse();

}

4. Buat Class baru dengan nama XMLParser.java lalu ketikan kode berikut

package com.agusharyanto.net.map.direction.json;

import java.net.URL;
import java.io.IOException;
import java.net.MalformedURLException;
import java.io.InputStream;

import android.util.Log;

public class XMLParser {
        // names of the XML tags
        protected static final String MARKERS = "markers";
        protected static final String MARKER = "marker";

        protected URL feedUrl;

        protected XMLParser(final String feedUrl) {
                try {
                        this.feedUrl = new URL(feedUrl);
                } catch (MalformedURLException e) {
                        Log.d("*****", "XML parser - " + feedUrl);
                }
        }

        protected InputStream getInputStream() {
                try {
                        return feedUrl.openConnection().getInputStream();
                } catch (IOException e) {
                        Log.d("****", "XML parser - " + feedUrl);
                        return null;
                }
        }
}

5. Buat Class baru dengan nama Segmen.java lalu ketikkan kode berikut

package com.agusharyanto.net.map.direction.json;

import com.google.android.maps.GeoPoint;

public class Segment {
        /** Points in this segment. **/
        private GeoPoint start;
        /** Turn instruction to reach next segment. **/
        private String instruction;
        /** Length of segment. **/
        private int length;
        /** Distance covered. **/
        private double distance;

        /**
         * Create an empty segment.
         */

        public Segment() {
        }

        /**
         * Set the turn instruction.
         * @param turn Turn instruction string.
         */

        public void setInstruction(final String turn) {
                this.instruction = turn;
        }

        /**
         * Get the turn instruction to reach next segment.
         * @return a String of the turn instruction.
         */

        public String getInstruction() {
                return instruction;
        }

        /**
         * Add a point to this segment.
         * @param point GeoPoint to add.
         */

        public void setPoint(final GeoPoint point) {
                start = point;
        }

        /** Get the starting point of this
         * segment.
         * @return a GeoPoint
         */

        public GeoPoint startPoint() {
                return start;
        }

        /** Creates a segment which is a copy of this one.
         * @return a Segment that is a copy of this one.
         */

        public Segment copy() {
                final Segment copy = new Segment();
                copy.start = start;
                copy.instruction = instruction;
                copy.length = length;
                copy.distance = distance;
                return copy;
        }

        /**
         * @param length the length to set
         */
        public void setLength(final int length) {
                this.length = length;
        }

        /**
         * @return the length
         */
        public int getLength() {
                return length;
        }

        /**
         * @param distance the distance to set
         */
        public void setDistance(double distance) {
                this.distance = distance;
        }

        /**
         * @return the distance
         */
        public double getDistance() {
                return distance;
        }

}

6. Buat Class baru dengan nama Route.java lalu ketikkan kode berikut

package com.agusharyanto.net.map.direction.json;

import java.util.ArrayList;
import java.util.List;

import com.google.android.maps.GeoPoint;

public class Route {
        private String name;
        private final List<GeoPoint> points;
        private List<Segment> segments;
        private String copyright;
        private String warning;
        private String country;
        private int length;
        private String polyline;

        public Route() {
                points = new ArrayList<GeoPoint>();
                segments = new ArrayList<Segment>();
        }

        public void addPoint(final GeoPoint p) {
                points.add(p);
        }

        public void addPoints(final List<GeoPoint> points) {
                this.points.addAll(points);
        }

        public List<GeoPoint> getPoints() {
                return points;
        }

        public void addSegment(final Segment s) {
                segments.add(s);
        }

        public List<Segment> getSegments() {
                return segments;
        }

        /**
         * @param name the name to set
         */
        public void setName(final String name) {
                this.name = name;
        }

        /**
         * @return the name
         */
        public String getName() {
                return name;
        }

        /**
         * @param copyright the copyright to set
         */
        public void setCopyright(String copyright) {
                this.copyright = copyright;
        }

        /**
         * @return the copyright
         */
        public String getCopyright() {
                return copyright;
        }

        /**
         * @param warning the warning to set
         */
        public void setWarning(String warning) {
                this.warning = warning;
        }

        /**
         * @return the warning
         */
        public String getWarning() {
                return warning;
        }

        /**
         * @param country the country to set
         */
        public void setCountry(String country) {
                this.country = country;
        }

        /**
         * @return the country
         */
        public String getCountry() {
                return country;
        }

        /**
         * @param length the length to set
         */
        public void setLength(int length) {
                this.length = length;
        }

        /**
         * @return the length
         */
        public int getLength() {
                return length;
        }

        /**
         * @param polyline the polyline to set
         */
        public void setPolyline(String polyline) {
                this.polyline = polyline;
        }

        /**
         * @return the polyline
         */
        public String getPolyline() {
                return polyline;
        }

}

7. Buat Class baru dengan nama GoogleParser.java, lalu ketikkan kode berikut

package com.agusharyanto.net.map.direction.json;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

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

import android.util.Log;

import com.google.android.maps.GeoPoint;

public class GoogleParser extends XMLParser implements Parser {
        /** Distance covered. **/
        private int distance;

        public GoogleParser(String feedUrl) {
                super(feedUrl);
        }

        /**
         * Parses a url pointing to a Google JSON object to a Route object.
         * @return a Route object based on the JSON object.
         */

        public Route parse() {
                // turn the stream into a string
                final String result = convertStreamToString(this.getInputStream());
                //Create an empty route
                final Route route = new Route();
                //Create an empty segment
                final Segment segment = new Segment();
                try {
                        //Tranform the string into a json object
                        final JSONObject json = new JSONObject(result);
                        //Get the route object
                        final JSONObject jsonRoute = json.getJSONArray("routes").getJSONObject(0);
                        //Get the leg, only one leg as we don't support waypoints
                        final JSONObject leg = jsonRoute.getJSONArray("legs").getJSONObject(0);
                        //Get the steps for this leg
                        final JSONArray steps = leg.getJSONArray("steps");
                        //Number of steps for use in for loop
                        final int numSteps = steps.length();
                        //Set the name of this route using the start & end addresses
                        route.setName(leg.getString("start_address") + " to " + leg.getString("end_address"));
                        //Get google's copyright notice (tos requirement)
                        route.setCopyright(jsonRoute.getString("copyrights"));
                        //Get the total length of the route.
                        route.setLength(leg.getJSONObject("distance").getInt("value"));
                        //Get any warnings provided (tos requirement)
                        if (!jsonRoute.getJSONArray("warnings").isNull(0)) {
                                route.setWarning(jsonRoute.getJSONArray("warnings").getString(0));
                        }
                        /* Loop through the steps, creating a segment for each one and
                         * decoding any polylines found as we go to add to the route object's
                         * map array. Using an explicit for loop because it is faster!
                         */
                        for (int i = 0; i < numSteps; i++) {
                                //Get the individual step
                                final JSONObject step = steps.getJSONObject(i);
                                //Get the start position for this step and set it on the segment
                                final JSONObject start = step.getJSONObject("start_location");
                                final GeoPoint position = new GeoPoint((int) (start.getDouble("lat")*1E6),
                                        (int) (start.getDouble("lng")*1E6));
                                segment.setPoint(position);
                                //Set the length of this segment in metres
                                final int length = step.getJSONObject("distance").getInt("value");
                                distance += length;
                                segment.setLength(length);
                                segment.setDistance(distance/1000);
                                //Strip html from google directions and set as turn instruction
                                segment.setInstruction(step.getString("html_instructions").replaceAll("<(.*?)*>", ""));
                                //Retrieve & decode this segment's polyline and add it to the route.
                                route.addPoints(decodePolyLine(step.getJSONObject("polyline").getString("points")));
                                //Push a copy of the segment to the route
                                route.addSegment(segment.copy());
                        }
                } catch (JSONException e) {
                        Log.e(e.getMessage(), "Google JSON Parser - " + feedUrl);
                }
                return route;
        }

        /**
         * Convert an inputstream to a string.
         * @param input inputstream to convert.
         * @return a String of the inputstream.
         */

        private static String convertStreamToString(final InputStream input) {
        final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
        final StringBuilder sBuf = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sBuf.append(line);
            }
        } catch (IOException e) {
                Log.e(e.getMessage(), "Google parser, stream2string");
        } finally {
            try {
                input.close();
            } catch (IOException e) {
                Log.e(e.getMessage(), "Google parser, stream2string");
            }
        }
        return sBuf.toString();
    }

        /**
         * Decode a polyline string into a list of GeoPoints.
         * @param poly polyline encoded string to decode.
         * @return the list of GeoPoints represented by this polystring.
         */

        private List<GeoPoint> decodePolyLine(final String poly) {
                int len = poly.length();
                int index = 0;
                List<GeoPoint> decoded = new ArrayList<GeoPoint>();
                int lat = 0;
                int lng = 0;

                while (index < len) {
                int b;
                int shift = 0;
                int result = 0;
                do {
                        b = poly.charAt(index++) - 63;
                        result |= (b & 0x1f) << shift;
                        shift += 5;
                } while (b >= 0x20);
                int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
                lat += dlat;

                shift = 0;
                result = 0;
                do {
                        b = poly.charAt(index++) - 63;
                        result |= (b & 0x1f) << shift;
                        shift += 5;
                } while (b >= 0x20);
                        int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
                        lng += dlng;

                decoded.add(new GeoPoint(
                        (int) (lat*1E6 / 1E5), (int) (lng*1E6 / 1E5)));
                }

                return decoded;
                }
}

8. Buat Class baru dengan nam RouteOverlay.java, lalu ketikkan kode berikut

package com.agusharyanto.net.map.direction.json;

import java.util.Iterator;
import java.util.List;

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.Projection;

public class RouteOverlay extends Overlay {
    /** GeoPoints representing this routePoints. **/
    private final List<GeoPoint> routePoints;
    /** Colour to paint routePoints. **/
    private int colour;
    /** Alpha setting for route overlay. **/
    private static final int ALPHA = 120;
    /** Stroke width. **/
    private static final float STROKE = 4.5f;
    /** Route path. **/
    private final Path path;
    /** Point to draw with. **/
    private final Point p;
    /** Paint for path. **/
    private final Paint paint;

    /**
     * Public constructor.
     *
     * @param route Route object representing the route.
     * @param defaultColour default colour to draw route in.
     */

    public RouteOverlay(final Route route, final int defaultColour) {
            super();
            routePoints = route.getPoints();
            colour = defaultColour;
            path = new Path();
            p = new Point();
            paint = new Paint();
    }

    @Override
    public final void draw(final Canvas c, final MapView mv,
                    final boolean shadow) {
            super.draw(c, mv, shadow);

            paint.setColor(colour);
            paint.setAlpha(ALPHA);
            paint.setAntiAlias(true);
            paint.setStrokeWidth(STROKE);
            paint.setStyle(Paint.Style.STROKE);

            redrawPath(mv);
            c.drawPath(path, paint);
    }

    /**
     * Set the colour to draw this route's overlay with.
     *
     * @param c  Int representing colour.
     */
    public final void setColour(final int c) {
            colour = c;
    }

    /**
     * Clear the route overlay.
     */
    public final void clear() {
            routePoints.clear();
    }

    /**
     * Recalculate the path accounting for changes to
     * the projection and routePoints.
     * @param mv MapView the path is drawn to.
     */

    private void redrawPath(final MapView mv) {
            final Projection prj = mv.getProjection();
            path.rewind();
            final Iterator<GeoPoint> it = routePoints.iterator();
            prj.toPixels(it.next(), p);
            path.moveTo(p.x, p.y);
            while (it.hasNext()) {
                    prj.toPixels(it.next(), p);
                    path.lineTo(p.x, p.y);
            }
            path.setLastPoint(p.x, p.y);
    }

}

9. Edit Class AndroidDirectionJSON.java, lalu ketikkan kode berikut

package com.agusharyanto.net.map.direction.json;

import android.graphics.Color;
import android.os.Bundle;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;

public class AndroidDirectionJSONActivity extends MapActivity {
	MapView myMapView = null;
	MapController myMC = null;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		myMapView = (MapView) findViewById(R.id.mapView);

		myMapView.setSatellite(false);

		// STARTING POINT
		GeoPoint startGP = new GeoPoint((int) (-6.3039 * 1E6),
				(int) (106.8267 * 1E6));

		// ENDING POINT
		GeoPoint endGP = new GeoPoint((int) (-6.29436 * 1E6),
				(int) (106.8859 * 1E6));
		//
		myMC = myMapView.getController();
		myMC.setCenter(startGP);
		myMC.setZoom(14);

		Route route = getDirections(startGP, endGP);
		RouteOverlay routeOverlay = new RouteOverlay(route, Color.BLUE);
		myMapView.getOverlays().add(routeOverlay);

		myMapView.getController().animateTo(startGP);
		myMapView.setBuiltInZoomControls(true);
		myMapView.displayZoomControls(true);

	}

	@Override
	protected boolean isRouteDisplayed() {
		// TODO Auto-generated method stub
		return false;
	}

	private Route getDirections(final GeoPoint start, final GeoPoint dest) {
		Parser parser;
		String surl = "http://maps.googleapis.com/maps/api/directions/json?";
		final StringBuffer sBuf = new StringBuffer(surl);
		sBuf.append("origin=");
		sBuf.append(start.getLatitudeE6() / 1E6);
		sBuf.append(',');
		sBuf.append(start.getLongitudeE6() / 1E6);
		sBuf.append("&destination=");
		sBuf.append(dest.getLatitudeE6() / 1E6);
		sBuf.append(',');
		sBuf.append(dest.getLongitudeE6() / 1E6);
		sBuf.append("&sensor=true&mode=driving");
		parser = new GoogleParser(sBuf.toString());
		Route r = parser.parse();
		return r;
	}

}

Dari kode diatas yang menjadi titik mulai nya adalah startGP dana titik akhirnya adala endGP.
untuk menggambar directionyan kode diatas memanggil method getDirection

10. Edit file AndroidManifest.xml, lalu ketikkan kode berikut

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.agusharyanto.net.map.direction.json"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="8" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <uses-library android:name="com.google.android.maps" />
        <activity
            android:name=".AndroidDirectionJSONActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

11. Saatnya kita merun projectnya, jika semua sudah benar maka hasilnya akan seperti ini

Semoga Bermanfaat,

Salam hangat

Agus Haryanto