Hi,

You should post this question on Stack Overflow (
http://stackoverflow.com/questions/tagged/android) or on the
android-developers group.

Thanks

-- Luke


On Thu, Sep 9, 2010 at 3:11 AM, anushree <[email protected]> wrote:

> hi,
> i am developing a google maps application for android based mobile
> devices..
> i trie loading the map but it is returning a null pointer exception..
> i am pasting my code here..
> package com.google.MapsProject;
>
> import android.app.Activity;
> import android.content.Context;
> import android.content.pm.ActivityInfo;
> import android.location.Criteria;
> import android.location.Location;
> import android.location.LocationListener;
> import android.location.LocationManager;
> import android.os.Bundle;
> import android.webkit.WebChromeClient;
> import android.webkit.WebView;
> import android.webkit.WebViewClient;
>
> public class MapsProject extends Activity implements LocationListener{
>    /** Called when the activity is first created. */
>        WebView webView;
>        private Location mostRecentLocation;
>    @Override
>    public void onCreate(Bundle savedInstanceState) {
>        super.onCreate(savedInstanceState);
>        setContentView(R.layout.main);
>        getLocation();
>        setupWebView();
>
> this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
>
>    }
>    public void getLocation(){
>        LocationManager lm = (LocationManager)
> getSystemService(Context.LOCATION_SERVICE);
>        Criteria c = new Criteria();
>        c.setAccuracy(Criteria.ACCURACY_FINE);
>        String provider = lm.getBestProvider(c,true);
>        lm.requestLocationUpdates(provider, 1, 0, this);
>        mostRecentLocation = lm.getLastKnownLocation(provider);
>    }
>    public void setupWebView(){
>          final String centerURL = "javascript:centerAt(" +
>          mostRecentLocation.getLatitude() + "," +
>          mostRecentLocation.getLongitude()+ ")";
>          webView = (WebView) findViewById(R.id.webview);
>          webView.getSettings().setJavaScriptEnabled(true);
>          //Wait for the page to load then send the location information
>          webView.setWebViewClient(new WebViewClient());
>          webView.loadUrl("file:///android_asset/localmap.html");
>          /** Allows JavaScript calls to access application resources **/
>          webView.setWebChromeClient(new WebChromeClient());
>          webView.addJavascriptInterface(new JavaScriptInterface(),
> "android");
>        }
>        /** Sets up the interface for getting access to Latitude and
> Longitude data from device
>         **/
>        final class JavaScriptInterface {
>          public double getLatitude(){
>            return mostRecentLocation.getLatitude();
>          }
>          public double getLongitude(){
>            return mostRecentLocation.getLongitude();
>          }
>
>        }
>        @Override
>        public void onLocationChanged(Location location) {
>                // TODO Auto-generated method stub
>
>        }
>        @Override
>        public void onProviderDisabled(String provider) {
>                // TODO Auto-generated method stub
>
>        }
>        @Override
>        public void onProviderEnabled(String provider) {
>                // TODO Auto-generated method stub
>
>        }
>        @Override
>        public void onStatusChanged(String provider, int status, Bundle
> extras) {
>                // TODO Auto-generated method stub
>
>        }
> }
>
>
> local.html:
>
> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://
> www.w3.org/TR/html4/loose.dtd">
> <html>
> <head>
> <meta http-equiv="Content-Type" content="text/html;
> charset=ISO-8859-1">
> <title>Hello Maps</title>
> <script type = "text/javascript" src = "http://maps.google.com/maps/
> api/js?sensor=true"></script>
> <script type="text/javascript">
> var map;
> function initialize(){
>        var latitude = 0;
>    var longitude = 0;
>    if (window.android){
>      latitude = window.android.getLatitude();
>      longitude = window.android.getLongitude();
>    }
>    var myLatlng = new google.maps.LatLng(latitude,longitude);
>    var myOptions = {
>      zoom: 8,
>      center: myLatlng,
>      mapTypeId: google.maps.MapTypeId.ROADMAP
>    }
>    map = new google.maps.Map(document.getElementById("map_canvas"),
>      myOptions);
> }
> function centerAt(latitude,longitude){
>        myLatlng = new google.maps.LatLng(latitude,longitude);
>    map.panTo(myLatlng);
> }
>
> </script>
> </head>
> <body>
>
> </body>
> </html>
>
>
> can anyone please tell me why it is throwing a null pointer exception
> and what should i do to remove it???
>
> --
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>
>

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