谷歌地图路线 - 哪些API？ [英] Google Maps Directions - Which API?
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问题描述
我试图从用户的当前位置的方向，在应用程序，我建立一个用户定义的位置。这似乎是它应该是一个比较容易的事，但我被陷在要使用的API。
I'm trying to get the directions from the user's current location to a user defined location in the app that I'm building. This seems like it should be a relatively easy thing to do but I'm getting stuck on which API to use.
现在，我已经成功地挂接到谷歌的方向API 但在JSON它的返回是很奇怪的（他们已经增加了\ñ无处不在，使其可读），这表明，我认为这个API是不正确的移动。
Right now I've managed to hook up to the google directions API but the JSON it's returning is very strange (they've added a \n everywhere to make it human readable) which suggests to me that this API isn't the correct one for mobile.
我也看到了谷歌的地方API被推荐用于此目的，但我似乎无法找出如何从文档中使用它。
I've also seen the google places API being recommended for this purpose but I can't seem to find out how to use it from the documentation.
任何帮助是极大AP preciated，因为我只是一个titch混淆
Any help is greatly appreciated since I'm just a titch confused
编辑：只是为了澄清的问题是，我应该使用以获得方向的地图的API
Just to clarify the questions is which API I should be using to get directions for maps?
推荐答案
我不记得在那里我得到它，但这个班帮了我很多，它包括如果要绘制的路线。
I do not remember where I get it but this classes help me a lot, it includes if you want to draw the route.
GoogleParser.java
GoogleParser.java
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 com.google.android.maps.GeoPoint;
import com.monumentos.log.Logger;
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) {
Logger.appendLog( "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) {
Logger.appendLog( "Google parser, stream2string");
} finally {
try {
input.close();
} catch (IOException e) {
Logger.appendLog( "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;
}
}
Parser.java
Parser.java
public interface Parser {
public Route parse();
}
Route.java
Route.java
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;
}
}
RouteOverlay.java
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 = 200;
/** 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);
}
}
Segment.java
Segment.java
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;
}
}
XMLParser.java
XMLParser.java
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import com.monumentos.log.Logger;
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) {
Logger.appendLog( "XML parser - " + feedUrl);
}
}
protected InputStream getInputStream() {
try {
return feedUrl.openConnection().getInputStream();
} catch (IOException e) {
Logger.appendLog( "XML parser - " + feedUrl);
return null;
}
}
}
希望它会帮助你。
Hope it will helps you.
调用API的例子：
Parser parser;
String jsonURL = "http://maps.googleapis.com/maps/api/directions/json?";
final StringBuffer sBuf = new StringBuffer(jsonURL);
sBuf.append("origin=");
sBuf.append( points.get(0).getLatitudeE6()/1E6);
sBuf.append(',');
sBuf.append(points.get(0).getLongitudeE6()/1E6);
sBuf.append("&destination=");
sBuf.append(points.get(points.size()-1).getLatitudeE6()/1E6);
sBuf.append(',');
sBuf.append(points.get(points.size()-1).getLongitudeE6()/1E6);
sBuf.append("&sensor=true&mode="+routeMode);
Logger.appendLog(sBuf.toString());
parser = new GoogleParser(sBuf.toString());
Route r = parser.parse();
这篇关于谷歌地图路线 - 哪些API？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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