问题
i am making an android app using geo-location in android. i am using the location manager for getting the geo-location coordinates.
locationManager.requestLocationUpdates(provider, 0, 0, this);
Location location = locationManager.getLastKnownLocation(provider);
and using the postDelayed() function for continuously called the getLastKnownLocation() for the geo-location. and set the interval timing 1000 (1 sec). but i get the response after 20 seconds. Can any body explain me why it happens. i am new in android.
回答1:
Note that you shouldn't be calling getLastKnownLocation() every second if you have a Location Listener set up (which it looks like you do). Just use the latest values given in the onLocationChanged() callback.
This code works for me, it registers a Location Listener, which updates the lat/lon member variables, and then the Runnable runs with an initial interval of one second, and then every five seconds (5000 milliseconds) and displays the most current location value.
I put in a Toast to make sure that the Runnable is being run every 5 seconds by handler.postDelayed().
Here is the full Activity code:
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Handler;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity implements LocationListener {
LocationManager locationManager;
Handler handler;
Location location;
double latitude;
double longitude;
TextView lat;
TextView lon;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
handler = new Handler();
lat = (TextView) findViewById(R.id.latitudeTextView);
lon = (TextView) findViewById(R.id.longitudeTextView);
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, this);
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null){
latitude = location.getLatitude();
longitude = location.getLongitude();
}
handler.postDelayed(runLocation, 1000);
}
public Runnable runLocation = new Runnable(){
@Override
public void run() {
lat.setText(String.valueOf(latitude));
lon.setText(String.valueOf(longitude));
Toast.makeText(MainActivity.this, "location check", Toast.LENGTH_SHORT).show();
MainActivity.this.handler.postDelayed(MainActivity.this.runLocation, 5000);
}
};
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onLocationChanged(Location location) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
}
Edit:
As an alternative, you could take out the use of postDelayed(), and just use the onLocationChanged() events.
In the example below, I used both NETWORK_PROVIDER and GPS_PROVIDER.
This is needed in the AndroidManifest.xml:
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
Here is the modified code, which registers the Activity as a Location Listener for both Network location callbacks and GPS location callbacks, with a minimum time interval of one second. Note that events can come in at a greater interval than one second, but with the GPS location enabled, I saw them coming in every second (it was taking longer with only Network location enabled).
public class MainActivity extends ActionBarActivity implements LocationListener {
LocationManager locationManager;
Handler handler;
Location location;
double latitude;
double longitude;
TextView lat;
TextView lon;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
handler = new Handler();
lat = (TextView) findViewById(R.id.latitudeTextView);
lon = (TextView) findViewById(R.id.longitudeTextView);
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 0, this);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, this);
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null){
latitude = location.getLatitude();
longitude = location.getLongitude();
}
//handler.postDelayed(runLocation, 1000);
}
/*
public Runnable runLocation = new Runnable(){
@Override
public void run() {
lat.setText(String.valueOf(latitude));
lon.setText(String.valueOf(longitude));
Toast.makeText(MainActivity.this, "location check", Toast.LENGTH_SHORT).show();
MainActivity.this.handler.postDelayed(MainActivity.this.runLocation, 5000);
}
};
*/
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onLocationChanged(Location location) {
latitude = location.getLatitude();
longitude = location.getLongitude();
lat.setText(String.valueOf(latitude));
lon.setText(String.valueOf(longitude));
Toast.makeText(MainActivity.this, "location changed: " + latitude + " " + longitude, Toast.LENGTH_SHORT).show();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
}
回答2:
Use this class as common class.
package com.ibl.commonClass;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
// First get location from Network Provider
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener Calling this function will stop using GPS in your
* app
* */
public void stopUsingGPS() {
if (locationManager != null) {
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude() {
if (location != null) {
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude() {
if (location != null) {
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
*
* @return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog On pressing Settings button will
* lauch Settings Options
* */
public void showSettingsAlert() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog
.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(
Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
and this code put at in your activity in oncreate Method
GPSTracker gps;
gps = new GPSTracker(NearMeActivity.this);
if (gps.canGetLocation()) {
latitude = gps.getLatitude();
longitude = gps.getLongitude();
// Toast.makeText(
// getApplicationContext(),
// "Your Location is - \nLat: " + latitude + "\nLong: "
// + longitude, Toast.LENGTH_LONG).show();
} else {
gps.showSettingsAlert();
}
Log.e("latlong", "" + latitude + "" + longitude);
回答3:
use google map api v2
example
public class MapActivity extends FragmentActivity {
protected GoogleMap map;
protected LatLng start;
protected LatLng end;
TextView tvDistance,tvTime;
CameraPosition mCameraPosition;
// LatLng currentLocation ;
Context context;
public static boolean loadMapChk = false;
double getlatitute, getlongitute;
String addressGeo;
/**
* This activity loads a map and then displays the route and pushpins on it.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map);
context = this;
Bundle bundle = getIntent().getExtras();
if (bundle != null) {
getlatitute = bundle.getDouble("getlatitute");
getlongitute = bundle.getDouble("getlongitute");
addressGeo = bundle.getString("addressGeo");
}
tvDistance = (TextView) findViewById(R.id.tvDistance);
tvTime = (TextView) findViewById(R.id.tvTime);
SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
map = fm.getMap();
map.setMyLocationEnabled(true);
map.setOnMyLocationChangeListener(myLocationChangeListener);
}
private GoogleMap.OnMyLocationChangeListener myLocationChangeListener = new GoogleMap.OnMyLocationChangeListener() {
@Override
public void onMyLocationChange (Location location) {
LatLng loc = new LatLng (location.getLatitude(), location.getLongitude());
// Toast.makeText(getApplicationContext(),"location.getLongitude()>>>>>>>"+location.getLongitude(),Toast.LENGTH_LONG).show();
// map.animateCamera(CameraUpdateFactory.newLatLngZoom(loc, 16.0f));
Bitmap bitmapicon = BitmapFactory.decodeResource(context.getResources(),
R.drawable.start_blue);
map.addMarker(new MarkerOptions().position(
new LatLng(location.getLatitude(), location.getLongitude())).title("My Location").icon(BitmapDescriptorFactory.fromBitmap(bitmapicon)));
if (!loadMapChk)
{
map.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 12.5f), 4000, null);
loadMapChk = true;
}
start = new LatLng(location.getLatitude(), location.getLongitude());
end = new LatLng(getlatitute, getlongitute);
Bitmap bitmapiconEnd = BitmapFactory.decodeResource(context.getResources(),
R.drawable.end_green);
map.addMarker(new MarkerOptions().position(
new LatLng(getlatitute, getlongitute)).title(addressGeo).icon(BitmapDescriptorFactory.fromBitmap(bitmapiconEnd)));
Routing routing = new Routing(Routing.TravelMode.DRIVING);
routing.registerListener(routingListener);
routing.execute(start, end);
}
};
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
loadMapChk = false;
}
public RoutingListener routingListener = new RoutingListener() {
@Override
public void onRoutingSuccess(PolylineOptions mPolyOptions, Route route) {
PolylineOptions polyOptions = new PolylineOptions();
polyOptions.color(Color.CYAN);
polyOptions.width(8);
polyOptions.addAll(mPolyOptions.getPoints());
tvDistance.setText("Distance : "+route.getDistanceText());
tvTime.setText("Time : "+route.getDurationText());
// Toast.makeText(getApplicationContext(), "Distance : "+route.getDistanceText()+" & Time = "+route.getDurationText(),6).show();
map.addPolyline(polyOptions);
// Start marker
MarkerOptions options = new MarkerOptions();
// End marker
options = new MarkerOptions();
options.position(end);
options.icon(BitmapDescriptorFactory.fromResource(R.drawable.end_green));
map.addMarker(options);
}
@Override
public void onRoutingStart() {
// TODO Auto-generated method stub
}
@Override
public void onRoutingFailure() {
// TODO Auto-generated method stub
}
};
}
回答4:
Use timer handeller to implement delay.
Total time= Time delay+ Server response
You might be facing problem because of that
来源：https://stackoverflow.com/questions/30274500/getting-geolocation-after-20-seconds