Android-Maps-Extensions异步加载标记图像

Question

I'm trying to show images (downloaded from a server) as map markers on a Google Map. I'm using Android-Maps-Extensions because i wasn't happy with Google Map-Utils performance.

Now i'm wondering how to load map marker images aynchronously with AME. The task is to show the image itself if it is not a cluster. If it is a cluster, i want to display the image of the first marker and the number of elements in the cluster.

Up to this point i've done the following:

1) Setup the Map Clusterer

private void setupMapClusterer() {
    mClusterOptions = new EClusterOptionsProvider(getContext());
    ClusteringSettings clusteringSettings = new ClusteringSettings();
    clusteringSettings.addMarkersDynamically(true);
    clusteringSettings.clusterOptionsProvider(mClusterOptions);
    mMap.setClustering(clusteringSettings);
}

2) Create the Cluster Options Provider

public EClusterOptionsProvider(Context context) {
    mClusterOptions = new ClusterOptions();
    mContext = context;
    mIconGenerator = new IconGenerator(context);

    // Inflate Layout
    View markerView = LayoutInflater.from(context).inflate(R.layout.map_marker, null);
    mImageView = (ImageView) markerView.findViewById(R.id.map_marker_image);
    mTextView = (TextView) markerView.findViewById(R.id.map_marker_text);

    // Setup Icon Generator
    mIconGenerator.setContentView(markerView);
}

public Bitmap createIcon(Bitmap bmp, String text) {
    mImageView.setImageBitmap(bmp);
    mTextView.setText(text);
    return mIconGenerator.makeIcon();
}

@Override
public ClusterOptions getClusterOptions(List<Marker> list) {
    // Get Bitmap from first marker
    Marker first = list.get(0);
    mClusterOptions.icon(BitmapDescriptorFactory.fromBitmap(mIconGenerator.makeIcon()));
    return mClusterOptions;
}

This gives me a Map where clusters have my custom view (which is correct), but i can't figure out where to download the images and how to put them into the single markers and especially the clusters.

Of course i don't want to download all images in advance (we're talking about 500+) images.

On a sidenode: I'm using Volley to dl the images asynchronously.

Answer 1

I created simple example of using clustering and loading markers async.
Hope you find some useful here. https://github.com/pengrad/android-maps-async-markers

We will load icons with Glide, I found it more stable than Picasso.
Call loadIconMarker for every marker you are adding to the map.

MarkerOptions markerOptions = ...
// you should pass some icon before new loaded, or leave default one
//markerOptions.icon(BitmapDescriptorFactory.fromResource(R.drawable.default_marker));
Marker marker = mMap.addMarker(markerOptions);
loadMarkerIcon(marker);


private void loadMarkerIcon(final Marker marker) {
    Glide.with(this).load("http://www.myiconfinder.com/uploads/iconsets/256-256-a5485b563efc4511e0cd8bd04ad0fe9e.png")
            .asBitmap().fitCenter().into(new SimpleTarget<Bitmap>() {
        @Override
        public void onResourceReady(Bitmap bitmap, GlideAnimation<? super Bitmap> glideAnimation) {
            BitmapDescriptor icon = BitmapDescriptorFactory.fromBitmap(bitmap);
            marker.setIcon(icon);
        }
    });
}

Create ClusterIcon is a little harder. This is my ClusterOptionsProvider.
I use base bitmap R.drawable.m1 and add text on it representing number of markers in cluster.

public class ClusterIconProvider implements ClusterOptionsProvider {

    Resources resources;
    Paint paint;
    Bitmap base;

    public ClusterIconProvider(Resources resources) {
        this.resources = resources;

        paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.WHITE);
        paint.setTextAlign(Paint.Align.CENTER);
        paint.setTextSize(15);

        base = BitmapFactory.decodeResource(resources, R.drawable.m1);
    }

    @Override
    public ClusterOptions getClusterOptions(List<Marker> list) {
        Bitmap bitmap = base.copy(Bitmap.Config.ARGB_8888, true);

        Rect bounds = new Rect();
        String text = String.valueOf(list.size());
        paint.getTextBounds(text, 0, text.length(), bounds);
        float x = bitmap.getWidth() / 2.0f;
        float y = (bitmap.getHeight() - bounds.height()) / 2.0f - bounds.top;

        Canvas canvas = new Canvas(bitmap);
        canvas.drawText(text, x, y, paint);
        BitmapDescriptor icon = BitmapDescriptorFactory.fromBitmap(bitmap);

        return new ClusterOptions().anchor(0.5f, 0.5f).icon(icon);
    }
}