Android - Google Map Basic Usage and Sample Code

Hello

first go over this

Important classes\interface :

interface OnMapReadyCallback

• callback

• onMapReady(GoogleMap map) - called when map is ready

FragmentActivity

• Activity that want to use the Fragment API
• API :

• FragmentManager getSupportFragmentManager ()

FragmentManager

• interface to interact with fragment objects inside an activity
• API :

• Fragment findFragmentById (int id) :

• used to get fragment inside the activity using their resource id
• result can be casted to SupportMapFragment

Fragment

• basically it is a gui component which lives inside an Activity
• nice explaination is here

SupportMapFragment

• inherits Fragment
• API

• void getMapAsync (OnMapReadyCallback callback) -set a callback that will be calledwhen the map is ready

GoogleMap

• API

• void setMyLocationEnabled (boolean enabled) :

• Enables or disables the my-location layer. 
• requires  permission for eitherACCESS_COARSE_LOCATION or ACCESS_FINE_LOCATION 
• setting the boolean to true will show the circle button and false will hide it. it will center the map to the device location when enabled and provided the location is available. (it is not always working for me , i can see the button but press on it cause some times nothing)

• void moveCamera (CameraUpdate update) :

• reposition the camera according to  CameraUpdate 
• CameraUpdate can be CameraUpdateFactory.newLatLngZoom( new LatLng(32.811,34.981), 13) . so in this case the camera will zoom around this location. 13 is the value of the zoom ,recommended to be between 2- 21

•  Marker addMarker (MarkerOptions options)

• add marker to the map
•  e.g. addMarker(new MarkerOptions()

                .title("Haifa")

                .snippet("Home Town")

                .position(LatLng(32.811,34.981)));

will position a marker at 32.811,34.981. click on it and you will see the title and snippet

Sample Code 

MainActivity.java
/**
 * This shows how to create a simple activity with a map and a marker on the map.
 */
public class MainActivity extends FragmentActivity implements OnMapReadyCallback {

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

        SupportMapFragment mapFragment =
                (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    /**
     * This is where we can add markers or lines, add listeners or move the camera. In this case, we
     * just add a marker near Haifa.
     */
    @Override
 
    public void onMapReady(GoogleMap map) {
        LatLng Haifa = new LatLng(32.811,34.981);

        map.setMyLocationEnabled(true);
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(Haifa, 13));

        map.addMarker(new MarkerOptions()
                .title("Haifa")
                .snippet("Home Town")
                .position(Haifa));
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/map"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  class="com.google.android.gms.maps.SupportMapFragment"/>

AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.trygooglemaps"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />
  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
  <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
     
         <!--   THIS KEY IS PER PACKAGE !!!! -->
    <meta-data android:name="com.google.android.geo.API_KEY"
    android:value="AIzaSyCgth2vzXi1r6AQzW87qNjU8dKbjxlZtYU"/>
   
     <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />
     
    </application>

</manifest>

you can get the sample here

References :

• https://developers.google.com/maps/documentation/android-api/
• https://developers.google.com/maps/documentation/android-api/start

Nathan