BasicMapActivity.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.google.mcommerce.sample.android.chapter09.googleMap;

import android.os.Bundle;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.mcommerce.sample.android.R;

/**
 * This shows how to create a simple activity with a map and a marker on the
 * map.
 * <p>
 * Notice how we deal with the possibility that the Google Play services APK is
 * not installed/enabled/updated on a user's device.
 */
public class BasicMapActivity extends android.support.v4.app.FragmentActivity {
	/**
	 * Note that this may be null if the Google Play services APK is not
	 * available.
	 */
	private GoogleMap mMap;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.c09_basic_demo);
		setUpMapIfNeeded();
	}

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

	/**
	 * Sets up the map if it is possible to do so (i.e., the Google Play
	 * services APK is correctly installed) and the map has not already been
	 * instantiated.. This will ensure that we only ever call
	 * {@link #setUpMap()} once when {@link #mMap} is not null.
	 * <p>
	 * If it isn't installed {@link SupportMapFragment} (and
	 * {@link com.google.android.gms.maps.MapView MapView}) will show a prompt
	 * for the user to install/update the Google Play services APK on their
	 * device.
	 * <p>
	 * A user can return to this Activity after following the prompt and
	 * correctly installing/updating/enabling the Google Play services. Since
	 * the Activity may not have been completely destroyed during this process
	 * (it is likely that it would only be stopped or paused),
	 * {@link #onCreate(Bundle)} may not be called again so we should call this
	 * method in {@link #onResume()} to guarantee that it will be called.
	 */
	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();
			}
		}
	}

	/**
	 * This is where we can add markers or lines, add listeners or move the
	 * camera. In this case, we just add a marker near Africa.
	 * <p>
	 * This should only be called once and when we are sure that {@link #mMap}
	 * is not null.
	 */
	private void setUpMap() {
		mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title(
				"Marker"));
	}
}