我正在使用谷歌地图API。我已经能够让用户选择一个位置，用户选择的位置将通过共享首选项保存。当用户在该位置时，它调用方法但是它仅检查用户是否在用户打开应用程序时的位置，并且即使打开应用程序并且用户前往该位置，该应用程序也需要重新启动该方法被调用。我该怎么做才能连续检查用户是否在该位置，即使该应用程序已关闭。
以下是代码：
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private PlaceAutocompleteAdapter mPlaceAutoCompleteAdapter;
private static final LatLngBounds LAT_LNG_BOUNDS = new LatLngBounds(
new LatLng(-40, -168), new LatLng(71,136));
private AutoCompleteTextView mSearchText;
private static final float METRES_100 = 100;
private GoogleMap mMap;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
LocationRequest mLocationRequest;
private static double latit;
private static double longi;
private static final LatLng POINTA = new LatLng(latit,longi);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkLocationPermission();
}
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if (DataPersistLoc.getLocation(MapsActivity.this).toString() == "") {
} else {
List<Address> addressList = null;
Geocoder geocoder = new Geocoder(this);
try {
addressList = geocoder.getFromLocationName(DataPersistLoc.getLocation(MapsActivity.this).toString(), 1);
} catch (IOException e) {
e.printStackTrace();
}
Address address = addressList.get(0);
LatLng latLng = new LatLng(address.getLatitude(), address.getLongitude());
mMap.addMarker(new MarkerOptions().position(latLng).title("Marker"));
mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
}
//Initialize Google Play Services
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.getUiSettings().setZoomGesturesEnabled(true);
mMap.getUiSettings().setCompassEnabled(true);
}
}
else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
public void changeType(View view)
{
if(mMap.getMapType() == GoogleMap.MAP_TYPE_NORMAL)
{
mMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
}
else
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
}
public void onSearch(View view) {
AutoCompleteTextView location_tf = (AutoCompleteTextView) findViewById(R.id.TFaddress);
if (TextUtils.isEmpty(location_tf.getText())) {
Toast.makeText(MapsActivity.this, "Enter Location",
Toast.LENGTH_LONG).show();
} else {
String location = location_tf.getText().toString();
List<Address> addressList = null;
if (location != null || !location.equals("")) {
Geocoder geocoder = new Geocoder(this);
try {
addressList = geocoder.getFromLocationName(location, 1);
} catch (IOException e) {
e.printStackTrace();
}
SharedPreferences.Editor editor = prefs.edit();
Address address = addressList.get(0);
LatLng latLng = new LatLng(address.getLatitude(), address.getLongitude());
latit = address.getLatitude();
//saves latitude value to shared preference
putDoubleLat(MapsActivity.this);
longi = address.getLongitude();
//saves latitude value to shared preference
putDoubleLong(MapsActivity.this);
mMap.addMarker(new MarkerOptions().position(latLng).title("Marker"));
mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
}
}
}
private static SharedPreferences prefs;
public static long LatPref = 0;
public static String latPref = "LatPref";
public static long LongPref = 0;
public static String longPref = "LongPref";
public static void putDoubleLat(Context context) {
prefs = context.getSharedPreferences("com.mobile.counterappmobile", context.MODE_PRIVATE);
LatPref = prefs.getLong(latPref, (long) latit);
prefs.edit().putLong(latPref, Double.doubleToRawLongBits(latit)).commit();
}
public static double getDoubleLat(Context context) {
SharedPreferences prefs = context.getSharedPreferences("com.mobile.counterappmobile", context.MODE_PRIVATE);
return Double.longBitsToDouble(prefs.getLong(latPref, Double.doubleToLongBits(LatPref)));
}
public static void putDoubleLong(Context context) {
prefs = context.getSharedPreferences("com.mobile.counterappmobile", context.MODE_PRIVATE);
LongPref = prefs.getLong(longPref, (long) longi);
prefs.edit().putLong(longPref, Double.doubleToRawLongBits(longi)).commit();
}
public static double getDoubleLong(Context context) {
SharedPreferences prefs = context.getSharedPreferences("com.mobile.counterappmobile", context.MODE_PRIVATE);
return Double.longBitsToDouble(prefs.getLong(longPref, Double.doubleToLongBits(LongPref)));
}
@Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
@Override
public void onConnectionSuspended(int i) {
}
//----------------------------------------------------------------------------
//Checks if user is at selected location
@Override
public void onLocationChanged(Location location) {
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng1 = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng1);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
mCurrLocationMarker = mMap.addMarker(markerOptions);
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng1));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
SharedPreferences prefs = getSharedPreferences("com.mobile.counterappmobile", MODE_PRIVATE);
//Checks if user is at selected location
Location target = new Location("target");
for(LatLng point : new LatLng[]{POINTA}) {
target.setLatitude(getDoubleLat(MapsActivity.this));
target.setLongitude(getDoubleLong(MapsActivity.this));
if(location.distanceTo(target) < METRES_100) {
Toast.makeText(MapsActivity.this, "You Are At This Location",
Toast.LENGTH_LONG).show();
} else {
}
}
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
public boolean checkLocationPermission(){
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Asking user if explanation is needed
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted. Do the
// contacts-related task you need to do.
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
// Permission denied, Disable the functionality that depends on this permission.
Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
// other 'case' lines to check for other permissions this app might request.
// You can add here other case statements according to your requirement.
}
}
}