Android Google Maps V2 - MapView in XML

RestrictedMapView.java

package com.example.vaibhavjani.geojsonexample;

import android.content.Context;
import android.graphics.Point;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;

import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMapOptions;
import com.google.android.gms.maps.MapView;
import com.google.android.gms.maps.MapsInitializer;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.VisibleRegion;

public class RestrictedMapView extends MapView {

    public static float MAX_ZOOM = 20;
    public static float MIN_ZOOM = 5;
    public static float MIN_ZOOM_FOR_FLING = 7;

    public static double MAX_LONGITUDE = 183.61;
    public static double MIN_LONGITUDE = 159.31;
    public static double MAX_LATITUDE = -32.98;
    public static double MIN_LATITUDE = -53.82;

    public static double DEF_LATITUDE = -41.78;
    public static double DEF_LONGITUDE = 173.02;
    public static float DEF_ZOOM = 7;

    private Handler mHandler = new Handler();
    private Context mContext;
    private VisibleRegion mLastCorrectRegion = null;
    private boolean mIsInAnimation = false;

    public RestrictedMapView(Context c, AttributeSet a, int o) {
        super(c, a, o);
        init(c);
    }
    public RestrictedMapView(Context c, AttributeSet a) {
        super(c, a);
        init(c);
    }
    public RestrictedMapView(Context c) {
        super(c);
        init(c);
    }

    public RestrictedMapView(Context c, GoogleMapOptions o) {
        super(c, o);
        init(c);
    }

    private GestureDetector mGestureDetector = null;
    private GestureDetector.SimpleOnGestureListener mGestudeListener =
            new GestureDetector.SimpleOnGestureListener() {

        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            if (mIsInAnimation) return false;
            GoogleMap map = getMap();
            LatLng target = map.getCameraPosition().target;
            Point screenPoint = map.getProjection().toScreenLocation(target);
            Point newPoint = new Point(screenPoint.x + (int)distanceX, screenPoint.y + (int)distanceY);
            LatLng mapNewTarget = map.getProjection().fromScreenLocation(newPoint);
            CameraUpdate update = CameraUpdateFactory.newLatLngZoom(
                    mapNewTarget,map.getCameraPosition().zoom);         
            tryUpdateCamera(update, 0); 
            return true;
        }

        @Override
        public boolean onFling (MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            if (mIsInAnimation) return false;
            GoogleMap map = getMap();
            double zoom = map.getCameraPosition().zoom;
            if (zoom < MIN_ZOOM_FOR_FLING) 
                return false;
            int velocity = (int) Math.sqrt(velocityX * velocityX + velocityY * velocityY);
            if (velocity < 500) return false;
            double k1 = 0.002d; /*exipemental*/
            double k2 = 0.002d;/*exipemental*/

            LatLng target = map.getCameraPosition().target;
            Point screenPoint = map.getProjection().toScreenLocation(target);
            Point newPoint = new Point(screenPoint.x - (int)(velocityX * k1 * zoom * zoom/*exipemental*/),
                    screenPoint.y - (int)(velocityY * k1 * zoom * zoom/*exipemental*/));
            LatLng mapNewTarget = map.getProjection().fromScreenLocation(newPoint);
            CameraUpdate update = CameraUpdateFactory.newLatLngZoom(
                    mapNewTarget,map.getCameraPosition().zoom); 
            tryUpdateCamera(update, (int)(velocity * k2 * zoom * zoom) /*exipemental*/);    
            return true;
        }
    };  
    private ScaleGestureDetector mScaleGestureDetector = null;
    private ScaleGestureDetector.SimpleOnScaleGestureListener mScaleGestudeListener =
            new ScaleGestureDetector.SimpleOnScaleGestureListener() {

        @Override
        public boolean onScale (ScaleGestureDetector detector) {
            if (mIsInAnimation) return false;

            GoogleMap map = getMap();
            double zoom = map.getCameraPosition().zoom;

            double k = 1d / detector.getScaleFactor();
            int x = (int) detector.getFocusX();
            int y = (int) detector.getFocusY();
            LatLng mapFocus = map.getProjection().
                    fromScreenLocation(new Point(x, y));
            LatLng target = map.getCameraPosition().target;

            zoom = zoom + Math.log(detector.getScaleFactor()) / Math.log(2d);
            if (zoom < MIN_ZOOM)  
                if (zoom == MIN_ZOOM) return false;
                else zoom = MIN_ZOOM;
            if (zoom > MAX_ZOOM) 
                if (zoom == MAX_ZOOM) return false;
                else zoom = MAX_ZOOM;

            double dx = norm(mapFocus.longitude) - norm(target.longitude);
            double dy = mapFocus.latitude - target.latitude;
            double dk = 1d - 1d / k;
            LatLng newTarget = new LatLng(target.latitude - dy * dk, 
                    norm(target.longitude) - dx * dk);

            CameraUpdate update = CameraUpdateFactory.newLatLngZoom(newTarget, (float) zoom);           
            tryUpdateCamera(update, 0);         
            return true;
        }
    };


    private void tryUpdateCamera(CameraUpdate update, int animateTime) {
        GoogleMap map = getMap();
        final VisibleRegion reg = map.getProjection().getVisibleRegion();
        if (animateTime <= 0) {
            map.moveCamera(update);
            checkCurrentRegion(reg);
        } else {
            mIsInAnimation = true;
            map.animateCamera(update, animateTime, new GoogleMap.CancelableCallback() {
                @Override
                public void onFinish() {
                    mIsInAnimation = false;
                    checkCurrentRegion(reg);
                }
                @Override
                public void onCancel() {
                    mIsInAnimation = false;
                    checkCurrentRegion(reg);
                }
            });
        }
    }

    private void checkCurrentRegion(VisibleRegion oldReg) {
        GoogleMap map = getMap();
        VisibleRegion regNew = map.getProjection().getVisibleRegion();
        if (checkBounds(regNew)) {
            mLastCorrectRegion = regNew;
        } else {
            if (mLastCorrectRegion != null)
                oldReg = mLastCorrectRegion;
            mIsInAnimation = true;
            map.animateCamera(CameraUpdateFactory.newLatLngBounds(
                    oldReg.latLngBounds, 0),
                    200, new GoogleMap.CancelableCallback() {
                        @Override
                        public void onFinish() {
                            mIsInAnimation = false;
                        }                       
                        @Override
                        public void onCancel() {
                            mIsInAnimation = false;
                        }
                    });

        }
    }

    /**
     * 
     * 
     * @param lonVal
     * @return
     */
    private double norm(double lonVal) {
        while (lonVal > 360d) lonVal -= 360d;
        while (lonVal < -360d) lonVal += 360d;
        if (lonVal < 0) lonVal = 360d + lonVal;
        return lonVal;
    }

    private double denorm(double lonVal) {
        if (lonVal > 180d) lonVal = -360d + lonVal; 
        return lonVal;
    }

    private boolean checkBounds(VisibleRegion reg) {
        double left = Math.min(
                Math.min(norm(reg.farLeft.longitude), norm(reg.nearLeft.longitude)),
                Math.min(norm(reg.farRight.longitude), norm(reg.nearRight.longitude)));
        double right = Math.max(
                Math.max(norm(reg.farLeft.longitude), norm(reg.nearLeft.longitude)),
                Math.max(norm(reg.farRight.longitude), norm(reg.nearRight.longitude)));
        double top = Math.max( 
                Math.max(reg.farLeft.latitude, reg.nearLeft.latitude),
                Math.max(reg.farRight.latitude, reg.nearRight.latitude));
        double bottom = Math.min( 
                Math.min(reg.farLeft.latitude, reg.nearLeft.latitude),
                Math.min(reg.farRight.latitude, reg.nearRight.latitude));

        boolean limitBounds = left < MIN_LONGITUDE || right > MAX_LONGITUDE ||
                bottom < MIN_LATITUDE || top > MAX_LATITUDE;        
        return !limitBounds;
    }

    private void init(Context c) {
        try {
             MapsInitializer.initialize(c);
         } catch (Exception e) {
             e.printStackTrace();
         }
        mContext = c;
        mHandler.post(new Runnable() {          
            @Override
            public void run() {
                GoogleMap map = getMap();
                if (map != null) {
                    getMap().getUiSettings().setZoomControlsEnabled(false);
                    map.getUiSettings().setAllGesturesEnabled(false);
                    map.moveCamera(CameraUpdateFactory.newLatLngZoom(
                            new LatLng(DEF_LATITUDE, DEF_LONGITUDE), DEF_ZOOM));
                    mLastCorrectRegion = map.getProjection().getVisibleRegion();
                    mGestureDetector = new GestureDetector(mContext, mGestudeListener);
                    mScaleGestureDetector = new ScaleGestureDetector(mContext, mScaleGestudeListener);
                } else mHandler.post(this);
            }
        });
    }


    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        if (mGestureDetector != null) mGestureDetector.onTouchEvent(event);
        if (mScaleGestureDetector != null) mScaleGestureDetector.onTouchEvent(event);
        return super.onInterceptTouchEvent(event);
    }
}

some_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
    
    <com.google.android.gms.maps.MapView android:id="@+id/mapview"
        android:layout_width="fill_parent" 
        android:layout_height="fill_parent" />

</LinearLayout>

SomeFragment.java

 
public class SomeFragment extends Fragment {
 
	MapView mapView;
	GoogleMap map;
 
	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
		View v = inflater.inflate(R.layout.some_layout, container, false);
 
 		// Gets the MapView from the XML layout and creates it
		mapView = (MapView) v.findViewById(R.id.mapview);
		mapView.onCreate(savedInstanceState);
 
		// Gets to GoogleMap from the MapView and does initialization stuff
		map = mapView.getMap();
		map.getUiSettings().setMyLocationButtonEnabled(false);
		map.setMyLocationEnabled(true);

		// Needs to call MapsInitializer before doing any CameraUpdateFactory calls
		try {
			MapsInitializer.initialize(this.getActivity());
		} catch (GooglePlayServicesNotAvailableException e) {
			e.printStackTrace();
		}
		
		// Updates the location and zoom of the MapView
		CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(43.1, -87.9), 10);
		map.animateCamera(cameraUpdate);
 
		return v;
	}

	@Override
	public void onResume() {
		mapView.onResume();
		super.onResume();
	}
 
	@Override
	public void onDestroy() {
		super.onDestroy();
		mapView.onDestroy();
	}
 
	@Override
	public void onLowMemory() {
		super.onLowMemory();
		mapView.onLowMemory();
	}
 
}

SomeManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
	package="com.example"
	android:versionCode="1"
	android:versionName="1.0" >
	
	<uses-sdk
		android:minSdkVersion="8"
		android:targetSdkVersion="15" />
	
	<uses-permission android:name="android.permission.INTERNET"/>
	<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
	<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
	<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
	
	<uses-feature
		android:glEsVersion="0x00020000"
		android:required="true"/>
	
	<permission
		android:name="com.example.permission.MAPS_RECEIVE"
		android:protectionLevel="signature"/>
	<uses-permission android:name="com.example.permission.MAPS_RECEIVE"/>
	
	<application
		android:icon="@drawable/ic_launcher"
		android:label="@string/app_name"
		android:theme="@style/AppTheme" >
		
		<meta-data
			android:name="com.google.android.maps.v2.API_KEY"
			android:value="your_key"/>
		
		<activity
			android:name=".HomeActivity"
			android:label="@string/app_name" >
			<intent-filter>
				<action android:name="android.intent.action.MAIN" />
				<category android:name="android.intent.category.LAUNCHER" />
			</intent-filter>
		</activity>
	
	</application>

</manifest>