我正在尝试动态加载用户头像作为自定义标记。我的代码基于 google maps utils 演示，但不知何故它不起作用，它只加载一个图像而其他所有图像都是空的:

这是我的代码:

public class MapsActivity extends FragmentActivity implements ClusterManager.OnClusterItemClickListener<ModelUser>, ClusterManager.OnClusterItemInfoWindowClickListener<ModelUser> {

    private ClusterManager<ModelUser> mClusterManager;
    private GoogleMap mMap; // Might be null if Google Play services APK is not available.
    private QueryAPI query = new QueryAPI();
    private List<ModelUser> users = new ArrayList<ModelUser>();
    ImageLoader imageLoader = AppController.getInstance().getImageLoader();

    //UI
    NetworkImageView avatarImageView;
    TextView name;
    TextView infos;
    TextView distance;
    RelativeLayout detailView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        setUpMapIfNeeded();

        detailView = (RelativeLayout) findViewById(R.id.detailView);
        avatarImageView = (NetworkImageView) findViewById(R.id.imageView);
        name = (TextView) findViewById(R.id.name);
        infos = (TextView) findViewById(R.id.info);
        distance = (TextView) findViewById(R.id.distance);


        query.nearUsers(new QueryAPI.ApiResponse<List<ModelUser>>() {
            @Override
            public void onCompletion(List<ModelUser> result) {

                users = result;

                setUpClusterer();
            }
        });

    }

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }


    private void setUpMap() {
        mMap.setMyLocationEnabled(true);
    }

    private void setUpClusterer() {

        // Position the map.
        getMap().moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(46.155115, 2.473060), 5));

        // Initialize the manager with the context and the map.
        // (Activity extends context, so we can pass 'this' in the constructor.)
        mClusterManager = new ClusterManager<ModelUser>(this, getMap());

        // Point the map's listeners at the listeners implemented by the cluster
        // manager.
        getMap().setOnCameraChangeListener(mClusterManager);
        getMap().setOnMarkerClickListener(mClusterManager);
        mClusterManager.setRenderer(new PersonRenderer());
        mClusterManager.setOnClusterItemClickListener(this);
        mClusterManager.setOnClusterItemInfoWindowClickListener(this);

        // Add cluster items (markers) to the cluster manager.
        addItems();
    }

    private void addItems() {

        for (int i = 0; i < users.size(); i++) {

            ModelUser user = users.get(i);

            mClusterManager.addItem(user);
        }

    }

    protected GoogleMap getMap() {
        setUpMapIfNeeded();
        return mMap;
    }

    @Override
    public boolean onClusterItemClick(ModelUser item) {

        Log.d("User clicked:", item.getName());
        avatarImageView.setImageUrl(item.getAvatar_url(), imageLoader);
        name.setText(item.getName());
        infos.setText(item.getAge());
        double d = Double.parseDouble(item.getDistance());
        distance.setText( String.format("%.1f", d) + "Km");
        detailView.setVisibility(View.VISIBLE);
        return false;
    }

    @Override
    public void onClusterItemInfoWindowClick(ModelUser item) {

        Log.d("User Window clicked:", item.getName());
    }

    /**
     * Draws profile photos inside markers (using IconGenerator).
     * When there are multiple people in the cluster, draw multiple photos (using MultiDrawable).
     */
    private class PersonRenderer extends DefaultClusterRenderer<ModelUser> {
        private final IconGenerator mIconGenerator = new IconGenerator(getApplicationContext());
        private final UICircularImage mImageView;
        //private final int mDimension;

        public PersonRenderer() {
            super(getApplicationContext(), getMap(), mClusterManager);

            View profile = getLayoutInflater().inflate(R.layout.map_marker_item, null);
            mIconGenerator.setContentView(profile);
            mImageView = (UICircularImage) profile.findViewById(R.id.avatarImageView);

        }

        @Override
        protected void onBeforeClusterItemRendered(ModelUser user, MarkerOptions markerOptions) {
            // Draw a single person.
            // Set the info window to show their name.
           // mImageView.setImageUrl(user.getAvatar_url(), imageLoader);
            Picasso.with(getApplicationContext())
                .load(user.getAvatar_url())
                .noFade()
                .into(mImageView, new com.squareup.picasso.Callback() {
                    @Override
                    public void onSuccess() {

                       //reload the marker HERE

                    }

                    @Override
                    public void onError() {

                    }
                });
            Bitmap icon = mIconGenerator.makeIcon();
            markerOptions.icon(BitmapDescriptorFactory.fromBitmap(icon)).title(user.getName());
        }

    }

知道为什么吗？

编辑:我意识到有时它会加载所有图像，我认为问题出在异步任务上。所以我现在的问题是:如果我实现一个回调来了解 Picasso 何时完成加载图像，我该如何重新加载这个特定的标记？

最佳答案

我们将从 Picasso 加载原始位图，然后将其传递给代表当前用户的标记

Picasso.with(getApplicationContext())
        .load(user.getAvatar_url())
        .into(new com.squareup.picasso.Target() {
            @Override
            public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
                // let's find marker for this user
                Marker markerToChange = null;
                for (Marker marker : mClusterManager.getMarkerCollection().getMarkers()) {
                    if (marker.getPosition().equals(user.getPosition())) {
                        markerToChange = marker;
                        break;
                    }
                }
                // if found - change icon
                if (markerToChange != null) {
                    markerToChange.setIcon(BitmapDescriptorFactory.fromBitmap(bitmap));
                }
            }
            @Override
            public void onBitmapFailed(Drawable errorDrawable) {
            }
            @Override
            public void onPrepareLoad(Drawable placeHolderDrawable) {
            }
        });

我和毕加索也有一些问题。所以，我推荐使用 Glide

compile 'com.github.bumptech.glide:glide:3.5.2'



Glide.with(getApplicationContext()).
            load(user.getAvatar_url())
            .asBitmap()
            .fitCenter()
            .into(new SimpleTarget<Bitmap>() {
                @Override
                public void onResourceReady(Bitmap bitmap, GlideAnimation<? super Bitmap> glideAnimation) {
                    // let's find marker for this user
                    Marker markerToChange = null;
                    for (Marker marker : mClusterManager.getMarkerCollection().getMarkers()) {
                        if (marker.getPosition().equals(user.getPosition())) {
                            markerToChange = marker;
                            break;
                        }
                    }
                    // if found - change icon
                    if (markerToChange != null) {
                        markerToChange.setIcon(BitmapDescriptorFactory.fromBitmap(bitmap));
                    }
                }
            });

关于安卓 : how to reload custom markers once the image is downloaded via Picasso?，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32252022/