Develop Reference

Zoom mapview is lost draw line direction

I doing building a appplication direction from this point to that point on map google. My code run success, but when i zoom in map, draw line direction on map is lost. When zoom out map, my line draw appear. Can you help me!
this source code draw line between two point!
class MyOverLay extends Overlay {
private final List<GeoPoint> points;
private boolean drawStartEnd;
private int pathColor;
public MyOverLay(List<GeoPoint> pointToDraw) {
// TODO Auto-generated constructor stub
this(pointToDraw, Color.BLUE, true);
}
public MyOverLay(List<GeoPoint> points, int pathColor,
boolean drawStartEnd) {
this.points = points;
this.pathColor = pathColor;
this.drawStartEnd = drawStartEnd;
}
private void drawOval(Canvas canvas, Paint paint, Point point) {
Paint ovalPaint = new Paint(paint);
ovalPaint.setStyle(Paint.Style.FILL_AND_STROKE);
ovalPaint.setStrokeWidth(3);
ovalPaint.setColor(Color.BLUE);
int _radius = 7;
RectF oval = new RectF(point.x - _radius, point.y - _radius,
point.x + _radius, point.y + _radius);
canvas.drawOval(oval, ovalPaint);
}
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
long when) {
Projection projection = mapView.getProjection();
if (shadow == false && points != null) {
Point startPoint = null, endPoint = null;
Path path = new Path();
// We are creating the path
for (int i = 0; i < points.size(); i++) {
GeoPoint gPointA = points.get(i);
Point pointA = new Point();
projection.toPixels(gPointA, pointA);
if (i == 0) { // This is the start point
startPoint = pointA;
path.moveTo(pointA.x, pointA.y);
} else {
if (i == points.size() - 1)// This is the end point
endPoint = pointA;
path.lineTo(pointA.x, pointA.y);
}
}
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(pathColor);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(8);
paint.setAlpha(100);
if (getDrawStartEnd()) {
if (startPoint != null) {
drawOval(canvas, paint, startPoint);
}
if (endPoint != null) {
drawOval(canvas, paint, endPoint);
}
}
if (!path.isEmpty())
canvas.drawPath(path, paint);
}
return super.draw(canvas, mapView, shadow, when);
}
public boolean getDrawStartEnd() {
return drawStartEnd;
}
public void setDrawStartEnd(boolean markStartEnd) {
drawStartEnd = markStartEnd;
}
}

How to draw route using multiple geopoints?

I am implementing an android application for Map activity.
I am using Location listener for getting location updates. After updating location i am saving those updated latitude and longitude values in database.
I am able draw Route path From Source to destination using source latitude, longitude and destination latitude, longitude values. But using multiple latitude and longitude values of database at a time i want to draw the route path. I am using my RoutePath.java class to draw the route path for multiple latitudes and longitudes.Using those list of latitudes and longitudes i am able to draw the path, but it shows point to point stright line not shows the route path. See the below image...
If you observe carefully some points are on the route and some points are outside of route path. See again below image with full zooming...
Please help me if anyone knows the solution for this problem...
RoutePath.java:
public class RoutePath extends Overlay {
private int _pathColor;
private final List<GeoPoint> _points;
private boolean _drawStartEnd;
public RoutePath(List<GeoPoint> points) {
this(points, Color.RED, true);
}
public RoutePath(List<GeoPoint> points, int pathColor,
boolean drawStartEnd) {
_points = points;
_pathColor = pathColor;
_drawStartEnd = drawStartEnd;
}
private void drawOval(Canvas canvas, Paint paint, Point point) {
Paint ovalPaint = new Paint(paint);
ovalPaint.setStyle(Paint.Style.FILL_AND_STROKE);
ovalPaint.setStrokeWidth(2);
int _radius = 6;
RectF oval = new RectF(point.x - _radius, point.y - _radius, point.x
+ _radius, point.y + _radius);
canvas.drawOval(oval, ovalPaint);
}
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
long when) {
Projection projection = mapView.getProjection();
if (shadow == false && _points != null) {
Point startPoint = null, endPoint = null;
Path path = new Path();
// We are creating the path
for (int i = 0; i < _points.size(); i++) {
GeoPoint gPointA = _points.get(i);
Point pointA = new Point();
projection.toPixels(gPointA, pointA);
if (i == 0) { // This is the start point
startPoint = pointA;
path.moveTo(pointA.x, pointA.y);
} else {
if (i == _points.size() - 1)// This is the end point
endPoint = pointA;
path.lineTo(pointA.x, pointA.y);
}
}
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(_pathColor);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(5);
paint.setAlpha(90);
if (getDrawStartEnd()) {
if (startPoint != null) {
drawOval(canvas, paint, startPoint);
}
if (endPoint != null) {
drawOval(canvas, paint, endPoint);
}
}
if (!path.isEmpty())
canvas.drawPath(path, paint);
}
return super.draw(canvas, mapView, shadow, when);
}
public boolean getDrawStartEnd() {
return _drawStartEnd;
}
public void setDrawStartEnd(boolean markStartEnd) {
_drawStartEnd = markStartEnd;
}
}

You got Straight line because the the GeoPoints are like that only..... means if you have a complete route paths then it will show according to your Geopoints....It all depends on GeoPoints.!

draw path manually in Google map

I am currently doing an android application which contains google map. In this map i want to draw a path manually between two points . one point is my current point and the other is the point marked by the user(draw by using draw method in overlay class,the code is given below). plz help me .
protected class Touchy extends Overlay {
#Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
long when) {
Paint paint = new Paint();
super.draw(canvas, mapView, shadow);
// Converts lat/lng-Point to OUR coordinates on the screen.
Point myScreenCoords = new Point();
mapView.getProjection().toPixels(geoPoint, myScreenCoords);
paint.setStrokeWidth(1);
paint.setARGB(255, 255, 255, 255);
paint.setStyle(Paint.Style.STROKE);
Bitmap bmp = BitmapFactory.decodeResource(getResources(),
R.drawable.source);
canvas.drawBitmap(bmp, myScreenCoords.x, myScreenCoords.y, paint);
for(int i=0;i<size;i++)
{
mapView.getProjection().toPixels(GP[i], myScreenCoords);
canvas.drawBitmap(bmp,myScreenCoords.x, myScreenCoords.y, paint);
}
return true;
}
#Override
public boolean onTouchEvent(MotionEvent e, final MapView m) {
// TODO Auto-generated method stub
System.out.println("Hiiiiiiiiiiiiiiiiiiii");
if (e.getAction() == MotionEvent.ACTION_DOWN) {
start = e.getEventTime();
int x = (int) e.getX();
int y = (int) e.getY();
touchedPoint = m.getProjection().fromPixels(x, y);
System.out.println(touchedPoint);
}
if (e.getAction() == MotionEvent.ACTION_UP) {
stop = e.getEventTime();
}
if (stop - start > 1500) {
AlertDialog alert = new AlertDialog.Builder(
LocationTrackerActivity.this).create();
alert.setTitle("Location Tracker");
alert.setMessage("Enter your Option");
alert.setButton("Mark", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
if (FlagPin == 0) {
OverlayItem overlayItem = new OverlayItem(
touchedPoint, "wazzup", "xd");
PinPoint custom = new PinPoint(d,
LocationTrackerActivity.this);
custom.insertPinpoint(overlayItem);
overlayList.add(custom);
FlagPin = 1;
destLat = touchedPoint.getLatitudeE6() / 1E6;
desLong = touchedPoint.getLongitudeE6() / 1E6;
}
}
});

If you know, two geo points, then follow this link to draw a path between those point.
http://lokeshatandroid.blogspot.in/2012/09/draw-path-between-two-geo-points.html
Already you know your current position GeoPoint and find the lat and long values of user pointed mark and follow the above link.

Drawing shapes in Android MapView independent of the zoom level

I need to draw shapes just like those you would create with custom maps on Google Maps, using Android's MapView.
In other words, if I draw a shape on the map, when I zoom out it should shrink, covering the same area of the map regardless of the zoom level.
Example following the Android Reference:
#Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when)
{
super.draw(canvas, mapView, shadow);
//---translate the GeoPoint to screen pixels---
Point screenPts = new Point();
mapView.getProjection().toPixels(p, screenPts);
Paint boxPaint = new Paint();
boxPaint.setColor(android.graphics.Color.WHITE);
boxPaint.setStyle(Paint.Style.FILL);
boxPaint.setAlpha(140);
canvas.drawCircle(screenPts.x, screenPts.y, 20, boxPaint);
return true;
}
This shows a white circle on the map, but if you zoom out, the circle is the same size. Perhaps using canvas is not right approach?
I need something like how Google Maps highlights neighborhoods or cities:
Any ideas? Thanks in advance!

I had the same problem myself, here's a full solution with demo locations:
import java.util.*;
import android.graphics.*;
import android.graphics.Paint.Style;
import android.graphics.Region.Op;
import android.os.Bundle;
import com.google.android.maps.*;
public class ShapeOverlayTest extends MapActivity {
private MapView m_map;
#Override
public void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
m_map = (MapView) findViewById(R.id.mapview);
m_map.displayZoomControls(true);
m_map.setBuiltInZoomControls(true);
}
#Override
protected void onStart() {
super.onStart();
Loc[][] areas = {
{
new Loc(51.51695436113811, -0.28686325139653757),
new Loc(51.5268179962453, -0.28118722558738923),
new Loc(51.526498459594215, -0.27779666308279755),
new Loc(51.52521530775356, -0.26943974607777654),
new Loc(51.52292555645698, -0.25813738590178786),
new Loc(51.52054465991048, -0.2498381618983569),
new Loc(51.51012230470141, -0.24509233633017083),
new Loc(51.50884762913046, -0.24465130560570497),
new Loc(51.50732063336974, -0.2441767643132881),
new Loc(51.50431624597833, -0.24473900326760137),
new Loc(51.49756328092904, -0.2714528238165076),
new Loc(51.50092541797557, -0.28360267232347336),
new Loc(51.50205958485736, -0.28490018935582045),
new Loc(51.50488447379555, -0.28681164237730944)
},
{
new Loc(51.50368617913765, -0.25313579464343156),
new Loc(51.51978611305675, -0.24842567405905958),
new Loc(51.51039382684418, -0.24460628015366626),
new Loc(51.508792552597576, -0.24397604687682156),
new Loc(51.50713008309719, -0.24346350415674722),
new Loc(51.502411013302684, -0.2508501075008919),
new Loc(51.502377240039664, -0.25160073203846817),
new Loc(51.50274364303565, -0.25204783703705536)
},
{
new Loc(51.49924084955314, -0.2858705706471945),
new Loc(51.50212820259818, -0.2791479893522646),
new Loc(51.49724510427319, -0.27427453152961206),
new Loc(51.49429724502515, -0.2799184038304611),
new Loc(51.494270969987404, -0.28180678948730314)
}
};
String[] areaNames = { "W3 Ealing", "W3 Hammersmith & Fulham", "W3 Hounslow" };
// for (Map.Entry<String, List<Loc>> area : m_areas.entrySet()) {
// // to have much less points and make sure they are in order
// // the demo data already has these properties
// // http://en.wikipedia.org/wiki/Gift_wrapping_algorithm#Pseudocode
// area.setValue(Algo.convexHull(area.getValue()));
// }
Map<String, List<GeoPoint>> areaMap = new HashMap<String, List<GeoPoint>>();
for (int i = 0; i < areaNames.length; i++) {
List<GeoPoint> points = new ArrayList<GeoPoint>();
for (int j = 0; j < areas[i].length; j++) {
points.add(areas[i][j].toGeoPoint());
}
areaMap.put(areaNames[i], points);
}
m_map.getOverlays().add(new AreasOverlay(areaMap));
// TODO determine location better, e.g. averaging area points
GeoPoint center = new GeoPoint(51509704, -270710);
m_map.getController().setCenter(center);
m_map.getController().setZoom(15);
}
#Override
protected boolean isRouteDisplayed() {
return false;
}
static class Loc {
private double m_lat;
private double m_lon;
public Loc(final double lat, final double lon) {
m_lat = lat;
m_lon = lon;
}
public GeoPoint toGeoPoint() {
return new GeoPoint((int) (m_lat * 1e6), (int) (m_lon * 1e6));
}
};
static class AreasOverlay extends Overlay {
private final Map<String, List<GeoPoint>> m_areas;
private final Paint m_paintFill;
private final Paint m_paintStroke;
private static final int ALPHA = 0x30ffffff; // 48 out of 255 transparent
private static final int[] COLORS =
{ Color.YELLOW, Color.MAGENTA, Color.CYAN, Color.RED, Color.GREEN, Color.BLUE };
static {
for (int i = 0; i < AreasOverlay.COLORS.length; i++) {
AreasOverlay.COLORS[i] &= AreasOverlay.ALPHA;
}
}
public AreasOverlay(final Map<String, List<GeoPoint>> areaMap) {
m_areas = areaMap;
// prepare paints
m_paintFill = new Paint();
m_paintFill.setStyle(Paint.Style.FILL);
m_paintStroke = new Paint(Paint.ANTI_ALIAS_FLAG);
m_paintStroke.setStyle(Style.STROKE);
m_paintStroke.setAntiAlias(true);
m_paintStroke.setStrokeWidth(3);
}
#Override
public void draw(final Canvas canvas, final MapView mapView, final boolean shadow) {
super.draw(canvas, mapView, shadow);
if (shadow) {
return;
}
Projection projection = mapView.getProjection();
List<Path> areaPaths = getPaths(projection, m_areas);
drawPaths(canvas, areaPaths);
}
private List<Path> getPaths(final Projection projection, final Map<String, List<GeoPoint>> areas) {
List<Path> areaPaths = new ArrayList<Path>(areas.size());
for (Map.Entry<String, List<GeoPoint>> entry : areas.entrySet()) {
List<GeoPoint> sourceList = entry.getValue();
Path path = new Path();
path.setFillType(Path.FillType.EVEN_ODD);
Iterator<GeoPoint> it = sourceList.iterator();
Point point = nextDrawPoint(projection, it);
path.moveTo(point.x, point.y);
while (it.hasNext()) {
point = nextDrawPoint(projection, it);
path.lineTo(point.x, point.y);
}
path.close();
areaPaths.add(path);
}
return areaPaths;
}
/**
* <ul>
* <li>Draw with different colors.
* <li>Draw strokes first for them to be always visible.
* <li>Draw fills next with each removing from the drawable area.
* </ul>
*/
private void drawPaths(final Canvas canvas, final List<Path> areaPaths) {
int currentColorIndex;
currentColorIndex = 0;
for (Path path : areaPaths) {
int currentColor = AreasOverlay.COLORS[currentColorIndex++];
currentColorIndex %= AreasOverlay.COLORS.length;
m_paintStroke.setColor(currentColor & 0xff7f7f7f); // make it darker by clearing the high bit
canvas.drawPath(path, m_paintStroke);
}
currentColorIndex = 0;
for (Path path : areaPaths) {
int currentColor = AreasOverlay.COLORS[currentColorIndex++];
currentColorIndex %= AreasOverlay.COLORS.length;
m_paintFill.setColor(currentColor);
canvas.drawPath(path, m_paintFill);
canvas.clipPath(path, Op.DIFFERENCE); // don't allow to draw over each other
}
}
private Point nextDrawPoint(final Projection projection, final Iterator<GeoPoint> it) {
GeoPoint geo = it.next();
Point p = new Point();
projection.toPixels(geo, p);
return p;
}
}
}

The radius for drawCircle is in pixels so it make sense that the circle is always the same size. You have to scale the radius based on the zoom level. The example below will graph a geometry from the JTS Topology Suite that will scale.
public class MapOverlay extends Overlay {
private static final String TAG = MapOverlay.class.getName();
// Allocate once and reuse
private final Paint mPaint = new Paint();
private final Path mPath = new Path();
// Region to highlight
private Geometry mGeometry;
/**
* #param geometry Region to highlight on map
*/
public MapOverlay(Geometry geometry) {
// Set region
mGeometry = geometry;
// Edit paint style
mPaint.setDither(true);
mPaint.setColor(Color.rgb(128, 136, 231));
mPaint.setAlpha(100);
mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(6);
}
/**
* Draw the overlay over the map.
*
* #see com.google.android.maps.Overlay#draw(Canvas, MapView, boolean)
*/
#Override
public void draw(Canvas canvas, MapView mapv, boolean shadow) {
super.draw(canvas, mapv, shadow);
if (mGeometry != null) {
// TODO There could be more than one geometries
Geometry g = mGeometry.getGeometryN(0);
final Point p = new Point();
boolean first = true;
mPath.reset();
for (Coordinate c : g.getCoordinates()) {
// Convert lat/lon to pixels on screen
// GeoPoint is immutable so allocation is unavoidable
Projection projection = mapv.getProjection();
projection.toPixels(new GeoPoint((int) (c.y * 1E6), (int) (c.x * 1E6)), p);
// Set path starting point to first coordinate
// otherwise default start is (0,0)
if (first) {
mPath.moveTo(p.x, p.y);
first = false;
}
// Add new point to path
mPath.lineTo(p.x, p.y);
}
}
// Draw the path with give paint
canvas.drawPath(mPath, mPaint);
}
Adapted from here: MapSelectionOverlay.java

This maybe what you are looking for: Can "overlay" size be zoomed together with the google map on android?
public class ImpactOverlay extends Overlay {
private static int CIRCLERADIUS = 0;
private GeoPoint geopoint;
public ImpactOverlay(GeoPoint point, int myRadius) {
geopoint = point;
CIRCLERADIUS = myRadius;
}
#Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
// Transfrom geoposition to Point on canvas
Projection projection = mapView.getProjection();
Point point = new Point();
projection.toPixels(geopoint, point);
// the circle to mark the spot
Paint circle = new Paint();
circle.setColor(Color.BLACK);
int myCircleRadius = metersToRadius(CIRCLERADIUS, mapView, (double)geopoint.getLatitudeE6()/1000000);
canvas.drawCircle(point.x, point.y, myCircleRadius, circle);
}
public static int metersToRadius(float meters, MapView map, double latitude) {
return (int) (map.getProjection().metersToEquatorPixels(meters) * (1/ Math.cos(Math.toRadians(latitude))));
}
}

What you need is a list of lat/lon points for each shape you want to draw on the map. In the onDraw method, you need to iterate over that list (for each shape you want to draw), and do this:
//---translate the GeoPoint to screen pixels---
Point screenPts = new Point();
mapView.getProjection().toPixels(p, screenPts);
then draw the shape on the canvas. IIRC that works correctly regardless of zoom, because the mapView is aware of the zoom level, and gives you the appropriate pixel location for the lat/long pair at that zoom level.

Loading GeoPoints / Path on MapView is taking forever. Any way to speed it up?

I am working with a custom MapView for an application. I have a database with a LOT of GPS datapoints saved and I am currently loading them using Overlays, then performing an .addAll on the MapView with the Overlays.
However, it is taking up to 2 minutes to load just a few hundred data points as a path on the MapView.
The code to load the Data Points is:
private void loadMap() {
//Load the specific data from the database
DBAdapter db = new DBAdapter(this);
try {
db.open();
Cursor mDataPoints = db.db.rawQuery("SELECT * FROM GPS_DATA)", null);
if ((mDataPoints != null) && (!mDataPoints.isClosed()) && (mDataPoints.moveToFirst())) {
mapMain.setFinishedLoading(false);
mapMain.getOverlays().clear();
if ((!mDataPoints.isClosed()) && (mDataPoints.moveToFirst())) {
while (!mDataPoints.isAfterLast()) {
this.drawPath(db,
DBAdapter.formatLong(mDataPoints, "data_id"),
DBAdapter.formatString(mDataPoints, "data_name"),
DBAdapter.formatString(mDataPoints, "data_type"));
mDataPoints.moveToNext();
}
}
mapMain.refreshDrawableState();
mapMain.setEnabled(true);
}
} finally {
db.close();
}
}
public void drawPath(DBAdapter db, long pDataID, String pDataName, String pDataType) {
Cursor mData = db.getPointDataByDataID(pDataID);
if ((!mData.isClosed()) && (mData.moveToFirst())) {
boolean vFirst = true;
int i = 0;
GeoPoint startGP;
GeoPoint geoPoint1;
GeoPoint geoPoint2 = null;
while (!mData.isAfterLast()) {
if (vFirst) {
startGP = new GeoPoint((int) (DBAdapter.formatDouble(mData, "latitude") * 1E6), (int) (DBAdapter.formatDouble(mData, "longitude") * 1E6));
mapMain.getOverlays().add(new Map_Route_Overlay(startGP, startGP, this.returnPathColor(pDataType), pDataName));
vFirst = false;
geoPoint2 = startGP;
} else {
geoPoint1 = geoPoint2;
geoPoint2 = new GeoPoint((int) (DBAdapter.formatDouble(mData, "latitude") * 1E6), (int) (DBAdapter.formatDouble(mData, "longitude") * 1E6));
if (geoPoint2.getLatitudeE6() != 22200000) {
mapMain.getOverlays().add(new Map_Route_Overlay(geoPoint1, geoPoint2, this.returnPathColor(pDataType), pDataName));
}
}
i += 1;
mData.moveToNext();
}
if (geoPoint2 != null) {
mapMain.getOverlays().add(new Map_Route_Overlay(geoPoint2, geoPoint2, this.returnDataColor(pDataType), pDataName));
}
}
mData.close();
}
public int returnDataColor(String pType) {
int vReturnData = Color.BLUE;
if (pType.trim().equals("S")) {
vReturnData = Color.RED;
}
return vReturnData;
}
And the code for the Map_Route_Overlay class is:
public final class Map_Route_Overlay extends Overlay {
private static String TAG = CoreFunctions.APP_TAG + "_MapRouteOverlay";
private GeoPoint geoPoint1;
private GeoPoint geoPoint2;
private int defaultColor = 999;
private String dataName = "";
public Map_Route_Overlay(GeoPoint pGeoPoint1, GeoPoint pGeoPoint2, int pColor, String pText) {
this.geoPoint1 = pGeoPoint1;
this.geoPoint2 = pGeoPoint2;
this.defaultColor = pColor;
this.dataName = pText;
}
public void setDataName(String pName) {
this.dataName = pName;
}
#Override
public boolean draw (Canvas canvas, MMMapView mapView, boolean shadow, long when) {
Projection projection = mapView.getProjection();
if (shadow == false) {
Paint paint = new Paint();
paint.setAntiAlias(true);
Point point = new Point();
projection.toPixels(this.geoPoint1, point);
paint.setColor(this.defaultColor);
Point point2 = new Point();
projection.toPixels(this.geoPoint2, point2);
paint.setStrokeWidth(2);
paint.setAlpha(this.defaultColor == Color.parseColor("#6C8715")?220:120);
canvas.drawLine(point.x, point.y, point2.x,point2.y, paint);
}
return super.draw(canvas, mapView, shadow, when);
}
}
I have tried several options, including loading the data using Threads, but notifying the MapView to load the Overlays when completed was becoming a nightmare.
Just for reference, MMMapView is my custom MapView component, which for now just inherits MapView and implements two functions.

You really shouldn't be trying to display hundreds of Overlays on the screen at once, because you will get bad performance. Try limiting it to 10-20. Any more than that and it is too busy for the user anyway.
Also you should be using a thread to load the items from your database. What I do is I use a custom ItemizedOverlay, and add custom OverlayItems to it in a thread. Then once I am done loading I call mapView.postInvalidate(); so that they are displayed on the screen.

I am using this: http://code.google.com/p/mapview-overlay-manager/
It provides LazyLoading to load only the visible markers on the map.