TileOverlayDemoActivity.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.mapdemo;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.TileOverlayOptions;
import com.google.android.gms.maps.model.TileProvider;
import com.google.android.gms.maps.model.UrlTileProvider;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.Locale;

/**
 * This demonstrates how to add a tile overlay to a map.
 */
public class TileOverlayDemoActivity extends FragmentActivity {

    /** This returns moon tiles. */
    private static final String MOON_MAP_URL_FORMAT =
            "http://mw1.google.com/mw-planetary/lunar/lunarmaps_v1/clem_bw/%d/%d/%d.jpg";

    private GoogleMap mMap;

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

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

    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }

    private void setUpMap() {
        mMap.setMapType(GoogleMap.MAP_TYPE_NONE);

        TileProvider tileProvider = new UrlTileProvider(256, 256) {
            @Override
            public synchronized URL getTileUrl(int x, int y, int zoom) {
                // The moon tile coordinate system is reversed.  This is not normal.
                int reversedY = (1 << zoom) - y - 1;
                String s = String.format(Locale.US, MOON_MAP_URL_FORMAT, zoom, x, reversedY);
                URL url = null;
                try {
                    url = new URL(s);
                } catch (MalformedURLException e) {
                    throw new AssertionError(e);
                }
                return url;
            }
        };

        mMap.addTileOverlay(new TileOverlayOptions().tileProvider(tileProvider));
    }
}