Reputation: 531
i've been trying to create a map-related android app, but i realized that the onLocationChanged of my app had not been called, therefore the map always stay at the default area (US).
my code:
public class MapMainActivity extends MapActivity
implements OnClickListener, LocationListener {
MapView mapView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map_main);
//reference
mapView = (MapView)findViewById(R.id.map_view);
mapView.setBuiltInZoomControls(true);
this.findViewById(R.id.btn_satellite).setOnClickListener(this);
this.findViewById(R.id.btn_street).setOnClickListener(this);
}//onCreate
@Override
protected void onResume() {
super.onResume();
Toast.makeText(this, "GPS tracking started",
Toast.LENGTH_SHORT).show();
// Start location updates; 5s/5m
LocationManager locManager = (LocationManager)getSystemService(
Context.LOCATION_SERVICE);
locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,
5000, 0, this);
Criteria crit = new Criteria();
crit.setAccuracy(Criteria.ACCURACY_FINE);
String provider = locManager.getBestProvider(crit, true);
Location loc = locManager.getLastKnownLocation(provider);
}//onResume
@Override
protected void onPause() {
super.onPause();
Toast.makeText(this, "GPS tracking stopped",
Toast.LENGTH_SHORT).show();
LocationManager locManager = (LocationManager)getSystemService(
Context.LOCATION_SERVICE);
locManager.removeUpdates(this);
}//onPause
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(v == findViewById(R.id.btn_street))
{
mapView.setSatellite(false);
}//street view
else if (v == findViewById(R.id.btn_satellite))
{
mapView.setSatellite(true);
}
}//onClick
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}//isRouteDisplayed
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
double lat = location.getLatitude();
double lon = location.getLongitude();
TextView txtLat = (TextView)findViewById(R.id.txt_lat);
txtLat.setText(String.format("%.6f", lat));
TextView txtLon = (TextView)findViewById(R.id.txt_lon);
txtLon.setText(String.format("%.6f", lon));
MapView map = (MapView)findViewById(R.id.map_view);
map.getController().animateTo(new GeoPoint((int)(lat*1E6),//1000000),
(int)(lon*1E6)));
}//onLocationChanged
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
Toast.makeText(this, "GPS disabled",
Toast.LENGTH_SHORT).show();
}//onProviderDisabled
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
Toast.makeText(this, "GPS enabled",
Toast.LENGTH_SHORT).show();
}//onProviderEnabled
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}//onStatusChanged
}//class
the whole of my log cat when i run the app through my device (16/12/2011)
D/InputTransport(5357): Input channel constructed: name='40baf680 Toast (client)', ashmemFd=54, receivePipeFd=57, sendPipeFd=58
I/MapActivity(5357): Handling network change notification:CONNECTED
E/MapActivity(5357): Couldn't get connection factory client
I/ViewRoot(5357): !@FINISH DRAWING : sg.edu.tp/sg.edu.tp.SIP_TestMapActivity
I/ViewRoot(5357): !@finishDrawing is completed : sg.edu.tp/sg.edu.tp.SIP_TestMapActivity
I/ViewRoot(5357): !@FINISH DRAWING : Toast
I/ViewRoot(5357): !@finishDrawing is completed : Toast
D/InputTransport(5357): Input channel destroyed: name='40baf680 Toast (client)', ashmemFd=54, receivePipeFd=57, sendPipeFd=58
manifest :
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="sg.edu.tp"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="10" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name=".SIP_MLT_TestActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<uses-library android:name="com.google.android.maps" />
<activity android:name=".SIP_TestMapActivity"></activity>
<activity android:name=".SIP_TestDraw1Activity"></activity>
<activity android:name=".SIP_TestDraw2Activity"></activity>
</application>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
</manifest>
Upvotes: 5
Views: 5959
Reputation: 12367
Location stuiff is tricky. On one side, you need recent location fast, with best precision possible on the other side you do no like to drain battery fast. There are also differences between API levels. See this manual for detailed explanation:
http://android-developers.blogspot.com/2011/06/deep-dive-into-location.html
As for your original question - requersting location updates ist just a recomendation to location manager to send you those updates after something changes. It's no obliged to do so. Your GPS system may be not fine enough (and is certainly not) to detect snall location changes while leashed on USB cable. For testing purposes, you could create mock provider and manipulate it with outher application.
Upvotes: 0
Reputation: 3608
Are you testing that while moving about or while sitting tethered to your dev machine with USB and watching logcat?
If sitting at dev machine, I suspect you're not able to move the 5 meters required to trigger a location change event as you requested in your call to requestLocationUpdates
From API docs: .
If minDistance is greater than 0, a location will only be broadcast if the device moves by minDistance meters.
try reducing the min distance param in that call to zero and see what happens.
locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,5000, 0, this);
You probably dont want to leave that at zero for anything other than testing.
If that doesnt help you might try to see that your GPS is working at all by doing something like this in your onResume, after you ask for locationUpdates:
Criteria crit = new Criteria();
crit.setAccuracy(Criteria.ACCURACY_FINE);
String provider = lm.getBestProvider(crit, true);
Location loc = lm.getLastKnownLocation(provider);
and see if you are getting good location info.
Upvotes: 1