在我的应用程序中，我想显示用户的当前位置，如果位置发生更改，它将显示一条警报消息以更改位置。问题是即使手机的 GPS 关闭，它也会显示位置更改消息。可能是什么原因？
这是我的代码：
protected void onResume() {
/**
* get saved Location from shared preference
*
*/
SharedPreferences sPrefs = PreferenceManager
.getDefaultSharedPreferences(Activity_Home.this);
String getL = sPrefs.getString(Utility.KEY_USER_LAT, "0.000000");
String getLo = sPrefs.getString(Utility.KEY_USER_LONG, "0.000000");
getLat = Double.parseDouble(getL);
getLog = Double.parseDouble(getLo);
gps = new GpsTracker(Activity_Home.this);
/**
* Get user current latitude and longitude and match them to stored
* latitude and longitude if distance between these latitude then Pop up
* will be show
*
* @author Ankit
*/
if (gps.canGetLocation()) {
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
System.out.println("Latitude is " + getLat);
if (getLat > 0.0) {
Location locationA = new Location("point A");
locationA.setLatitude(getLat);
locationA.setLongitude(getLog);
Location locationB = new Location("point B");
locationB.setLatitude(latitude);
locationB.setLongitude(longitude);
distance = locationA.distanceTo(locationB);
// Toast.makeText(Activity_Home.this,
// "Distance is :"+Double.toString(distance),
// Toast.LENGTH_LONG).show();
distance = distance / 1000000;
int getDistance = (int) (distance * 1000000);
System.out.println("Distance is " + getDistance);
if (getDistance > 100) {
showWarningMessage();
}
}
String lat = String.valueOf(latitude);
String lon = String.valueOf(longitude);
SharedPreferences sPref = PreferenceManager
.getDefaultSharedPreferences(Activity_Home.this);
SharedPreferences.Editor sEdit = sPref.edit();
sEdit.putString(Utility.KEY_USER_LAT, lat);
sEdit.putString(Utility.KEY_USER_LONG, lon);
sEdit.commit();
} else {
gps.showSettingsAlert();
}
super.onResume();
}
// Method for show an Alert dialog for user if user's location changed''
public void showWarningMessage() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(
Activity_Home.this);
alertDialog.setCancelable(false);
// Setting Dialog Title
alertDialog.setTitle("Location Changed");
// Setting Dialog Message
alertDialog
.setMessage("It seems your location has changed, would you like to change the Branch now?");
// On pressing Settings button
alertDialog.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(Activity_Home.this,
Activity_Settings.class);
startActivity(intent);
dialog.cancel();
}
});
// on pressing cancel button
alertDialog.setNegativeButton("No",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
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 = 100; // 100 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);
System.out.println("=====isGPSEnabled:
"+isGPSEnabled+"====isNetworkEnabled: "+isNetworkEnabled);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
System.out.println("=====notgps");
} 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);
alertDialog.setCancelable(false);
// Setting Dialog Title
alertDialog.setTitle("Enable GPS");
// 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();
// alertDialog.;
}
@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;
}
}