我不知道如何使用这个 MapView 库

Question

I've been trying to create an indoor map with a Zoom functionality.I found the library "MapView" ( https://github.com/peterLaurence/MapView ) which is exactly what I would need to achieve what I want. Sadly all of the documentation is in Kotlin and I have no knowledge of Kotlin.

I tried to make a simple programm to start with. I wanted to simply show the map on the screen but it doesn't get drawn at all. I don't get any errors either so I don't really know what I can do.

Here is my code

public class MainActivity extends AppCompatActivity {

    private MapView mapView;
    private TileStreamProvider tileStreamProvider;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mapView= findViewById(R.id.view);

        mapView = new MapView(this);

        tileStreamProvider = new TileStreamProvider() {
            @Nullable
            @Override
            public InputStream getTileStream(int row, int col, int zoomLvl) {
                InputStream inputStream = null;

                AssetManager assetManager = MainActivity.this.getAssets();
                if (inputStream == null) {
                    try {
                        assetManager.open("tiles/esp/" + zoomLvl + '/' + row + '/' + col + ".jpg");
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                return inputStream;
            }
        };

        MapViewConfiguration config = new MapViewConfiguration(1, 8192, 8192, 256, tileStreamProvider);
        mapView.configure(config);


    }
}

Any help would be appreciated !

EDIT

I tried to do it another way, this time in a fragment and not directly on the main Activity by using the demo that is provided as example. But again since I don't really understand kotlin I may or may not have written soöe stuff the wrong way because I still end up with a white screen in the end.

Here is my code now

public class ExampleFragment extends Fragment {

    private ViewGroup parentView;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        parentView = container;
        MapView mapView = makeMapView(getContext());
        mapView.setId(R.id.mapview_id);
        mapView.setSaveEnabled(true);

        parentView.addView(mapView, 0);
        View v = inflater.inflate(R.layout.example_fragment, parentView, false);
        return v;
    }

    private MapView makeMapView(Context context) {
        TileStreamProvider tileStreamProvider = (row, col, zoomLvl) -> {
            try {
                context.getAssets().open("tiles/esp/" + zoomLvl + '/' + row + '/' + col + ".jpg");
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        };
        int tileSize = 256;
        MapViewConfiguration configuration = new MapViewConfiguration(5, 8192, 8192, tileSize, tileStreamProvider).setMaxScale(2f);

        MapView mapView = new MapView(context);
        mapView.configure(configuration);
        return mapView;
    }


}

SECOND EDIT

The code for my fragment looks like this now

public class ExampleFragment extends Fragment {

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        ViewGroup v = (ViewGroup) inflater.inflate(R.layout.example_fragment, container, false);

        MapView mapView = makeMapView(getContext());
        mapView.setId(R.id.mapview_id);
        mapView.setSaveEnabled(true);

        v.addView(mapView);
        return v;
    }

    private MapView makeMapView(Context context) {
        TileStreamProvider tileStreamProvider = (row, col, zoomLvl) -> {
            try {
                context.getAssets().open("tiles/esp/" + zoomLvl + '/' + row + '/' + col + ".jpg");
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        };
        int tileSize = 256;
        MapViewConfiguration configuration = new MapViewConfiguration(5, 8192, 8192, tileSize, tileStreamProvider).setMaxScale(2f);

        MapView mapView = new MapView(context);
        mapView.configure(configuration);
        return mapView;
    }


}

but it still doesn't work 

Answer 1

You need to add your instance of MapView into one of your view groups.

Assuming you have a linear layout with the id R.id.main in your activity:

LinearLayout mLayout = findViewById(R.id.linear_layout);
MapView mapView = new MapView(context);
mLayout.addView(mapView);