JMapViewer：地图刚加载时未设置平移和缩放

Question

我在 JMapViewer 上有两个自定义图像作为标记。我希望地图设置适当的平移和缩放，以便两个标记在地图显示上可见。我有一个按钮可以做到这一点。所以，发生的事情是地图在加载时没有缩放到这些标记；但是当我点击按钮时，它确实如此。有没有办法在加载时设置适当的平移和缩放？

public class PanelAcars extends javax.swing.JPanel implements JMapViewerEventListener  
{
    private final JMapViewerTree treeMap;

    public PanelAcars() 
    {
        super();
        initComponents(); // GUI components

        treeMap = new JMapViewerTree("Zones");

        // Listen to the map viewer for user operations so components will
        // receive events and update
        map().addJMVListener(this);

        setLayout(new BorderLayout());

        pnlAcarsMapView = new JPanel(new BorderLayout());
        JPanel panelTop = new JPanel();
        JPanel panelBottom = new JPanel();
        JPanel helpPanel = new JPanel();

        add(pnlAcarsMapView, BorderLayout.NORTH);
        add(helpPanel, BorderLayout.SOUTH);
        pnlAcarsMapView.add(panelTop, BorderLayout.NORTH);
        pnlAcarsMapView.add(panelBottom, BorderLayout.SOUTH);

        /* THIS BUTTON WORKS!!! */
        JButton button = new JButton("Zoom...");
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                map().setDisplayToFitMapMarkers();
            }
        });


        final JCheckBox showZoomControls = new JCheckBox("Show zoom controls");
        showZoomControls.setSelected(map().getZoomControlsVisible());
        showZoomControls.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                map().setZoomContolsVisible(showZoomControls.isSelected());
            }
        });
        panelBottom.add(showZoomControls);
        final JCheckBox scrollWrapEnabled = new JCheckBox("Scrollwrap enabled");
        scrollWrapEnabled.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                map().setScrollWrapEnabled(scrollWrapEnabled.isSelected());
            }
        });
        panelBottom.add(scrollWrapEnabled);
        panelBottom.add(button);

        add(treeMap, BorderLayout.CENTER);

        /* Add Airports to the map */
        LayerGroup mapGroupAirports = new LayerGroup("MapAirports");
        Layer mapLayerDep = mapGroupAirports.addLayer("MapDep");
        Layer mapLayerDest = mapGroupAirports.addLayer("MapDest");
        Layer mapLayerAlt = mapGroupAirports.addLayer("MapAlt");


        /* Add Plane to the map */
        Layer mapLayerPlane = new Layer("MapPlane");

        /* Set coordinates */
        Coordinate coordinatesPlane = new Coordinate(49.814284999, 98.642065999);
        Coordinate coordinatesDep = new Coordinate(23.814284999, 45.642065999);

        JMapViewerMarkerCustomImage markerPlane;
        JMapViewerMarkerCustomImage markerDep;

        Image imageMarkerPlane;
        Image imageMarkerDep;

        try 
        {
            imageMarkerPlane = ImageIO.read(this.getClass().getResource("/images/image1.png"));
            markerPlane = new JMapViewerMarkerCustomImage(coordinatesPlane,imageMarkerPlane);
            map().addMapMarker(markerPlane);

            imageMarkerDep = ImageIO.read(this.getClass().getResource("/images/image2.png"));
            markerDep = new JMapViewerMarkerCustomImage(coordinatesDep,imageMarkerDep);
            map().addMapMarker(markerDep);

            // AND THIS IS NOT WORKING AT LOADING!!!
            map().setDisplayToFitMapElements(true, true, true);

        } catch (IOException ex) {
            ex.printStackTrace();
        }


        map().addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                if (e.getButton() == MouseEvent.BUTTON1) {
                    map().getAttribution().handleAttribution(e.getPoint(), true);
                }
            }
        });

        map().addMouseMotionListener(new MouseAdapter() {
            @Override
            public void mouseMoved(MouseEvent e) {
                Point p = e.getPoint();
                boolean cursorHand = map().getAttribution().handleAttributionCursor(p);
                if (cursorHand) {
                    map().setCursor(new Cursor(Cursor.HAND_CURSOR));
                } else {
                    map().setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
                }
                //if (showToolTip.isSelected()) map().setToolTipText(map().getPosition(p).toString());
            }
        });

    }

非常感谢！

Answer 1

在地图的 tileLoadingFinished() 实现中调用 setDisplayToFitMapMarkers()。使用 boolean 变量 loaded，默认情况下为 false，下面的实现在第一个图块加载后调用该方法；父实现将 repaint() 任何后续图块。

private boolean loaded;

private class MyViewer extends JMapViewer {

    @Override
    public void tileLoadingFinished(Tile tile, boolean success) {
        super.tileLoadingFinished(tile, success);
        if (!loaded & success) {
            loaded = true;
            setDisplayToFitMapMarkers();
        }
    }
    …
}

要使用 JMapViewerTree 获得类似的结果，您需要更改在 JMapViewerTree 构造函数中实例化的 map。以下更改适用于 Demo.java：

…
private boolean loaded;
…
public JMapViewerTree(String name, boolean treeVisible) {
    …
    map = new JMapViewer() {
        @Override
        public void tileLoadingFinished(Tile tile, boolean success) {
            super.tileLoadingFinished(tile, success);
            if (!loaded & success) {
                loaded = true;
                setDisplayToFitMapMarkers();
            }
        }
    };
    …
}

顺便说一句，考虑扩展或替换 DefaultMapController，而不是 MouseAdapter，如建议 here。

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