我正在尝试使用Google Maps Api + JavaFx创建地图。在主类我读取JSON文件然后创建集群，程序点是将这些集群显示为具有位置数量的标记。
所以在主类中我读取JSON文件然后创建DBSCANClusterer clusterer = new DBSCANClusterer(coordinates, 2, 2);，我必须将其推送到类GoogleMap，其中JavaFX正在创建webView，依此类推。我也用这个在我的html文件中的脚本中使用java代码：
JSObject jsobj = (JSObject) webView.getEngine()
.executeScript("window");
jsobj.setMember("BrowserJavaObject", new BrowserJavaObject(clusterer));
然后必须在BrowserJavaObject类中进一步推送相同的东西，其中所有聚类计算都是。
我试图创建GoogleMap类的对象，但这不起作用。
那么如何让它发挥作用呢？或者这甚至可能吗？谢谢你的建议。
JSONMain类：
public class JsonMain {
static List<Coordinate> coordinates = new ArrayList<>();
private static final String ITEMS_NAME = "items";
private static final String LATITUDE_PROPERTY = "latitude";
private static final String LONGITUDE_PROPERTY = "longitude";
private static final String CRASH_NAME = "em_type_name";
static void parseCrashCoordinates(final JsonReader jsonReader, final ICoordinatesListener listener)
throws IOException {
// Reading JSON file
}
// Collecting all coordinates in ArrayList.
private static void testCollecting()
throws IOException {
// List<Coordinate> coordinates = new ArrayList<>();
readAndParse((lat, lng) -> coordinates.add(new Coordinate(lat, lng)));
System.out.println(coordinates.size());
}
public static void main(String[] args) throws IOException, URISyntaxException {
testCollecting();
// Initialize our clustering class with locations, minimum points in cluster and max Distance
DBSCANClusterer clusterer = new DBSCANClusterer(coordinates, 2, 2);
GoogleMap gm = new GoogleMap(clusterer);
gm.launch(GoogleMap.class);
}
GoogleMap类：
public class GoogleMap extends Application {
private DBSCANClusterer clusterer ;
public GoogleMap(DBSCANClusterer c) {
this.clusterer = c;
}
@Override
public void start(Stage stage) throws MalformedURLException {
File file = new File("C:/Users/Evgeny/git/Diploma_MSU/diploma/html/map.html");
URL url222 = file.toURI().toURL();
WebView webView = new WebView();
final WebEngine webEngine = webView.getEngine();
JSObject jsobj = (JSObject) webView.getEngine()
.executeScript("window");
jsobj.setMember("BrowserJavaObject", new BrowserJavaObject(clusterer));
webEngine.load(url222.toString());
// create scene
stage.setTitle("Web Map");
Scene scene = new Scene(webView,1000,700, Color.web("#666970"));
stage.setScene(scene);
// show stage
stage.show();
}
}
BrowserJavaObject类：
public class BrowserJavaObject {
private DBSCANClusterer clusterer ;
public BrowserJavaObject(DBSCANClusterer c) {
this.clusterer = c;
}
public String showMarkers() {
ArrayList<ArrayList<Coordinate>> clusters_raw= this.clusterer.performClustering();
ArrayList<Cluster> clusters = new ArrayList<>();
String pointsArray = " [ ";
for(int i=0; i<clusters_raw.size(); i++) {
Cluster c = new Cluster(clusters_raw.get(i));
clusters.add(c);
pointsArray += c.getLocationAsArray() + " , ";
}
pointsArray += "]";
System.out.println("Number Of Clusters Created: "+clusters.size());
return pointsArray;
}
}
map.html：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Map</title>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<style type="text/css">
html { height: 100% }
body { height: 100%; margin: 0; padding: 0 }
#map_canvas { height: 100% }
</style>
<script async defer type="text/javascript"
src="https://maps.googleapis.com/maps/api/js?callback=loadmap">
</script>
</head>
<body onload="loadmap()">
<div id="map_canvas" style="width:100%; height:100%"></div>
<script>
var map;
function loadmap(){
var options = {
zoom: 16,
center: new google.maps.LatLng(55.7558, 37.6173),
mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById("map_canvas"), options);
var markers = [];
// Call the Java code to calculate clusters data, and save the returned clusters into a variable
var markers_data = BrowserJavaObject.showMarkers();
for( var i=0; i<markers_data.length; i++ ){
var position = markers_data[i];
var icon = "data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%2238%22%20height%3D%2238%22%20viewBox%3D%220%200%2038%2038%22%3E%3Cpath%20fill%3D%22%23a22%22%20stroke%3D%22%23ccc%22%20stroke-width%3D%22.5%22%20d%3D%22M34.305%2016.234c0%208.83-15.148%2019.158-15.148%2019.158S3.507%2025.065%203.507%2016.1c0-8.505%206.894-14.304%2015.4-14.304%208.504%200%2015.398%205.933%2015.398%2014.438z%22%2F%3E%3Ctext%20transform%3D%22translate%2819%2018.5%29%22%20fill%3D%22%23fff%22%20style%3D%22font-family%3A%20Arial%2C%20sans-serif%3Bfont-weight%3Abold%3Btext-align%3Acenter%3B%22%20font-size%3D%2212%22%20text-anchor%3D%22middle%22%3E"
+ position[2]
+ "%3C%2Ftext%3E%3C%2Fsvg%3E";
// if(zoom > 11) icon = null; //Default to marker with no number if at city zom level
markers.push( new google.maps.Marker({
position: new google.maps.LatLng( position[0], position[1] ),
map: map,
title: position[2],
text: position[2],
icon: icon
})
);
}
}
</script>
</body>
</html>
所以地图已加载但没有集群。并且最终没有调用所有这些聚类方法，因为我的clusterer对象在其他类中没有进一步传递。
非常感谢！
答案 0 :(得分：1)
您正在以错误的方式使用Application类。 Application类代表您的整个应用程序，并负责其生命周期;特别是它有一个start()方法，当通过调用launch()启动JavaFX工具包时，会调用该方法。 Application课程并不代表您的用户界面的特定部分（这是GoogleMap课程所针对的部分）。
所以你应该让JsonMain成为Application的子类，而不是GoogleMap，你应该将启动代码移动到（恰当命名的）start()方法：< / p>
public class GoogleMap {
private DBSCANClusterer clusterer ;
private final WebView view ;
public GoogleMap(DBSCANClusterer c) throws MalformedURLException {
this.clusterer = c;
File file = new File("C:/Users/Evgeny/git/Diploma_MSU/diploma/html/map.html");
URL url222 = file.toURI().toURL();
view = new WebView();
final WebEngine webEngine = webView.getEngine();
JSObject jsobj = (JSObject) webView.getEngine()
.executeScript("window");
jsobj.setMember("BrowserJavaObject", new BrowserJavaObject(clusterer));
webEngine.load(url222.toString());
}
public Node getView() {
return view ;
}
}
和
public class JsonMain extends Application {
static List<Coordinate> coordinates = new ArrayList<>();
private static final String ITEMS_NAME = "items";
private static final String LATITUDE_PROPERTY = "latitude";
private static final String LONGITUDE_PROPERTY = "longitude";
private static final String CRASH_NAME = "em_type_name";
static void parseCrashCoordinates(final JsonReader jsonReader, final ICoordinatesListener listener)
throws IOException {
// Reading JSON file
}
// Collecting all coordinates in ArrayList.
private static void testCollecting()
throws IOException {
// List<Coordinate> coordinates = new ArrayList<>();
readAndParse((lat, lng) -> coordinates.add(new Coordinate(lat, lng)));
System.out.println(coordinates.size());
}
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage stage)
throws IOException, URISyntaxException, MalformedURLException {
testCollecting();
// Initialize our clustering class with locations, minimum points in cluster and max Distance
DBSCANClusterer clusterer = new DBSCANClusterer(coordinates, 2, 2);
GoogleMap gm = new GoogleMap(clusterer);
// create scene
stage.setTitle("Web Map");
Scene scene = new Scene(gm.getView(), 1000, 700, Color.web("#666970"));
stage.setScene(scene);
// show stage
stage.show();
}
}
您应该进一步重构，以便妥善区分您的疑虑;例如它可能不是你的Application类的工作来解析数据等。但这至少可以让你将参数传递给你的GoogleMap类，并允许你启动应用程序预定的方式。