android – DefaultClusterRenderer getMarker()在缩放时返回null

我想在点击时更改群集标记的背景.我通过这样做

@Override
onClusterClick(Cluster<MyObject> cluster) {
    Marker marker = renderer.getMarker(cluster);
    marker.setIcon(....);
}

对于一种情况,这很好用：当我放大或缩小时,簇标记的数量不会改变.例如,如果我有一个15集群和一个5集群,然后放大或缩小一个级别,保留相同的两个集群.现在单击其中一个renderer.getMarker(cluster)将返回null.如果它们在缩放后重新聚类,则getMarker不为null.

我的DefaultClusterRenderer在下面.我检查了onClusteredRendered上的标记,它永远不会为空.这是DefaultClusterRenderer中的错误还是我应该做些什么？

private class MyRenderer extends DefaultClusterRenderer<MyObject> {

    private IconGenerator iconGenerator;
    private float density;

    public MyRenderer(Context context,GoogleMap map,ClusterManager<MyObject> clusterManager) {
        super(context,map,clusterManager);
        density = context.getResources().getDisplayMetrics().density;
    }

    @Override
    protected void onBeforeClusterItemRendered(MyObject item,MarkerOptions markerOptions) {
        markerOptions.icon(BitmapDescriptorFactory.fromResource(R.drawable.my_pin));
    }

    @Override
    protected void onBeforeClusterRendered(Cluster<MyObject> cluster,MarkerOptions markerOptions) {
        if(iconGenerator == null) {
            iconGenerator = new IconGenerator(getActivity());
            iconGenerator.setContentView(makeTextView(getActivity()));
        }
        iconGenerator.setBackground(makeBackground(false));

        markerOptions.icon(BitmapDescriptorFactory.fromBitmap(iconGenerator.makeIcon(String.valueOf(cluster.getSize()))));
    }

    @Override
    protected void onClusterRendered(Cluster<MyObject> cluster,Marker marker) {
        super.onClusterRendered(cluster,marker);
        // Marker is never null here

    }

    @Override
    protected boolean shouldRenderAsCluster(Cluster<MyObject> cluster) {
        return cluster.getSize() > 1;
    }

    private ShapeDrawable makeBackground(boolean isClicked) {
        ShapeDrawable background = new ShapeDrawable(new OvalShape());
        background.setColorFilter(ContextCompat.getColor(getActivity(),isClicked ? R.color.cluster_marker_clicked : R.color.cluster_marker_unclicked),PorterDuff.Mode.SRC_ATOP);

        return background;
    }

    private SquareTextView makeTextView(Context context) {
        SquareTextView squareTextView = new SquareTextView(context);

        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(-2,-2);
        squareTextView.setLayoutParams(layoutParams);
        squareTextView.setTextColor(ContextCompat.getColor(getActivity(),R.color.white));

        squareTextView.setTypeface(Utils.getFontBold(getActivity()));

        squareTextView.setId(com.google.maps.android.R.id.text);
        int twelveDpi = (int) (12.0F * density);
        squareTextView.setPadding(twelveDpi,twelveDpi,twelveDpi);

        return squareTextView;
    }

    public IconGenerator getIconGenerator(boolean isClicked) {
        iconGenerator.setBackground(makeBackground(isClicked));
        return iconGenerator;
    }
}

初始化ClusterManager：

final ClusterManager<MyObject> mClusterManager = new ClusterManager<>(getActivity(),googleMap);
    mClusterManager.addItems(items);

    renderer = new CustomRenderer(getActivity(),googleMap,mClusterManager);
    mClusterManager.setRenderer(renderer);
    mClusterManager.cluster();

    mClusterManager.setOnClusterItemClickListener(this);

    googleMap.setOnMarkerClickListener(mClusterManager);

@antonio：这个初始化对我有用：

public class MapsActivity extends FragmentActivity
        implements ClusterManager.OnClusterClickListener<MyObject> {

    // ...

    private void setUpClusterer() {
        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(51.503186,-0.126446),10));

        mClusterManager = new ClusterManager<MyObject>(this,googleMap);
        mClusterManager.setOnClusterClickListener(this);
        renderer = new MyRenderer(this,mClusterManager);
        mClusterManager.setRenderer(renderer);

        googleMap.setOnCameraChangeListener(mClusterManager);
        googleMap.setOnMarkerClickListener(mClusterManager);

        addItems();
    }

    private void addItems() {
        // Set some lat/lng coordinates to start with.
        double lat = 51.5145160;
        double lng = -0.1270060;

        // Add ten cluster items in close proximity,for purposes of this example.
        for (int i = 0; i < 10; i++) {
            double offset = i / 60d;
            lat = lat + offset;
            lng = lng + offset;
            MyObject offsetItem = new MyObject(lat,lng);
            mClusterManager.addItem(offsetItem);
        }
    }

    @Override
    public boolean onClusterClick(final Cluster<MyObject> cluster) {
        Marker marker = renderer.getMarker(cluster);
        marker.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.my_newpin));

        return true;
    }
}

解决方法

在上面的情况下,无法让renderer.getMarker(cluster)返回一个标记.解决方法是创建：

Map <Cluster<MyObject>,Marker> clusterMarkerMap = new HashMap<>();

然后在DefaultClusterRenderer回调中添加它们,因为标记在那里永远不为null：

@Override
protected void onClusterRendered(Cluster<MyObject> cluster,Marker marker) {
    super.onClusterRendered(cluster,marker);
    clusterMarkerMap.put(cluster,marker);
}

因为DefaultClusterManager在摄像机位置更改时清除它们,所以在创建新的标记映射之前擦除它们：

googleMap.setOnCameraChangeListener(new GoogleMap.OnCameraChangeListener() {
        @Override
        public void onCameraChange(CameraPosition cameraPosition) {
            // Clear the map here because the markers will be recreated
            // when the manager is notified of a (zoom level) camera change
            if(zoomLevelChanged)
                 clusterMarkerMap.clear();
            mClusterManager.onCameraChange(cameraPosition);
        }
    });

现在我可以成功获得标记clusterMarkerMap.get(cluster)