如何創建JavaFx應用程序的實例並推送自己的參數？

我正嘗試使用Google Maps Api + JavaFx創建地圖。在主類中，我讀取JSON文件，然後創建聚類，程序的要點是將這些聚類顯示爲具有多個位置的標記。因此，在主類中，我讀取JSON文件，然後創建DBSCANClusterer clusterer = new DBSCANClusterer(coordinates, 2, 2);，我必須將其推送到類GoogleMap，其中JavaFX創建webView等等。此外，我用這個在我的HTML文件中使用Java代碼的腳本：如何創建JavaFx應用程序的實例並推送自己的參數？

JSObject jsobj = (JSObject) webView.getEngine() 
      .executeScript("window"); 
    jsobj.setMember("BrowserJavaObject", new BrowserJavaObject(clusterer));

然後同樣的事情必須在BrowserJavaObject類，所有的集羣計算是進一步推高。我試圖創建GoogleMap類的對象，但這不起作用。那麼如何讓它工作？或者甚至可能嗎？謝謝你的建議。

JSONMain類：

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的類：

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類：

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; 

} 
}

個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>

所以地圖加載，但沒有集羣存在。最終所有這些聚類方法都不會被調用，因爲我的clusterer對象沒有在其他類中進一步傳遞。

非常感謝！

來源

2017-10-08 Turtality

這太長了。考慮發佈[mcve] – c0der

您正在使用Application類錯誤的方式。 Application類表示您的整個應用程序並負責其生命週期;特別是它有一個start()方法，當您通過調用launch()啓動JavaFX工具包時爲您調用該方法。 Application類不代表您的用戶界面的特定部分（這是您的GoogleMap類似的用途）。

所以你應該讓JsonMain的Application，不GoogleMap一個子類，你應該將啓動代碼的（恰當地命名）start()方法：

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(); 

    } 

}

你應該進一步重構，以便正確區分你的擔憂;例如它可能不是Application類的解析數據等的工作。但是這至少會讓您將參數傳遞給GoogleMap類，並允許您以預定方式啓動應用程序。

來源

2017-10-08 22:44:18

如何創建JavaFx應用程序的實例並推送自己的參數？

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