我的MyMap Activity非常完美地获得了用户位置（拉特朗）。 但是当应用程序进入后台时，它会停止。 我的问题是- 我如何在此活动中集成服务。 我已在android清单文件中添加了必需的权限。
MyMap.java
public class MyMap extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
@BindView(R.id.location_result)
TextView txtLocationResult;
@BindView(R.id.updated_on)
TextView txtUpdatedOn;
@BindView(R.id.btn_start_location_updates)
Button btnStartUpdates;
@BindView(R.id.btn_stop_location_updates)
Button btnStopUpdates;
// location last updated time
private String mLastUpdateTime;
// location updates interval - 10sec
private static final long UPDATE_INTERVAL_IN_MILLISECONDS = 10000;
// fastest updates interval - 5 sec
// location updates will be received if another app is requesting the locations
// than your app can handle
private static final long FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS = 5000;
private static final int REQUEST_CHECK_SETTINGS = 100;
// bunch of location related apis
private FusedLocationProviderClient mFusedLocationClient;
private SettingsClient mSettingsClient;
private LocationRequest mLocationRequest;
private LocationSettingsRequest mLocationSettingsRequest;
private LocationCallback mLocationCallback;
private Location mCurrentLocation;
// boolean flag to toggle the ui
private Boolean mRequestingLocationUpdates;
//Firebase database connection
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference dbRef = database.getReference();
private FirebaseAuth auth;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_map);
//Get Firebase auth instance
auth = FirebaseAuth.getInstance();
//checking is user logged in
if (auth.getCurrentUser() == null) {
startActivity(new Intent(MyMap.this, LoginActivity.class));
finish();
}
//startTracking();
//Button signOut = findViewById(R.id.signOutButton);
ButterKnife.bind(this);
// initialize the necessary libraries
init();
// restore the values from saved instance state
restoreValuesFromBundle(savedInstanceState);
}
private void startTracking() {
// Requesting ACCESS_FINE_LOCATION using Dexter library
Dexter.withActivity(this)
.withPermission(Manifest.permission.ACCESS_FINE_LOCATION)
.withListener(new PermissionListener() {
@Override
public void onPermissionGranted(PermissionGrantedResponse response) {
mRequestingLocationUpdates = true;
startLocationUpdates();
}
@Override
public void onPermissionDenied(PermissionDeniedResponse response) {
if (response.isPermanentlyDenied()) {
// open device settings when the permission is
// denied permanently
openSettings();
}
}
@Override
public void onPermissionRationaleShouldBeShown(PermissionRequest permission, PermissionToken token) {
token.continuePermissionRequest();
}
}).check();
}
private void init() {
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
mSettingsClient = LocationServices.getSettingsClient(this);
mLocationCallback = new LocationCallback() {
@Override
public void onLocationResult(LocationResult locationResult) {
super.onLocationResult(locationResult);
// location is received
mCurrentLocation = locationResult.getLastLocation();
mLastUpdateTime = DateFormat.getTimeInstance().format(new Date());
updateLocationUI();
}
};
mRequestingLocationUpdates = false;
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setFastestInterval(FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder();
builder.addLocationRequest(mLocationRequest);
mLocationSettingsRequest = builder.build();
}
/**
* Restoring values from saved instance state
*/
private void restoreValuesFromBundle(Bundle savedInstanceState) {
if (savedInstanceState != null) {
if (savedInstanceState.containsKey("is_requesting_updates")) {
mRequestingLocationUpdates = savedInstanceState.getBoolean("is_requesting_updates");
}
if (savedInstanceState.containsKey("last_known_location")) {
mCurrentLocation = savedInstanceState.getParcelable("last_known_location");
}
if (savedInstanceState.containsKey("last_updated_on")) {
mLastUpdateTime = savedInstanceState.getString("last_updated_on");
}
}
updateLocationUI();
}
/**
* Update the UI displaying the location data
* and toggling the buttons
*/
private void updateLocationUI() {
if (mCurrentLocation != null) {
txtLocationResult.setText(
"Lat: " + mCurrentLocation.getLatitude() + ", " +
"Lng: " + mCurrentLocation.getLongitude()
);
// giving a blink animation on TextView
txtLocationResult.setAlpha(0);
txtLocationResult.animate().alpha(1).setDuration(300);
// location last updated time
txtUpdatedOn.setText("Last updated on: " + mLastUpdateTime);
dbRef.child("users").child("gourav").child("Lat").setValue(mCurrentLocation.getLatitude());
dbRef.child("users").child("gourav").child("Lng").setValue(mCurrentLocation.getLongitude());
dbRef.child("users").child("gourav").child("Time").setValue(mLastUpdateTime);
}
toggleButtons();
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putBoolean("is_requesting_updates", mRequestingLocationUpdates);
outState.putParcelable("last_known_location", mCurrentLocation);
outState.putString("last_updated_on", mLastUpdateTime);
}
private void toggleButtons() {
if (mRequestingLocationUpdates) {
btnStartUpdates.setEnabled(false);
btnStopUpdates.setEnabled(true);
} else {
btnStartUpdates.setEnabled(true);
btnStopUpdates.setEnabled(false);
}
}
/**
* Starting location updates
* Check whether location settings are satisfied and then
* location updates will be requested
*/
private void startLocationUpdates() {
mSettingsClient
.checkLocationSettings(mLocationSettingsRequest)
.addOnSuccessListener(this, new OnSuccessListener<LocationSettingsResponse>() {
@SuppressLint("MissingPermission")
@Override
public void onSuccess(LocationSettingsResponse locationSettingsResponse) {
Log.i(TAG, "All location settings are satisfied.");
Toast.makeText(getApplicationContext(), "Started location updates!", Toast.LENGTH_SHORT).show();
//noinspection MissingPermission
mFusedLocationClient.requestLocationUpdates(mLocationRequest,
mLocationCallback, Looper.myLooper());
updateLocationUI();
}
})
.addOnFailureListener(this, new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
int statusCode = ((ApiException) e).getStatusCode();
switch (statusCode) {
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
Log.i(TAG, "Location settings are not satisfied. Attempting to upgrade " +
"location settings ");
try {
// Show the dialog by calling startResolutionForResult(), and check the
// result in onActivityResult().
ResolvableApiException rae = (ResolvableApiException) e;
rae.startResolutionForResult(MyMap.this, REQUEST_CHECK_SETTINGS);
} catch (IntentSender.SendIntentException sie) {
Log.i(TAG, "PendingIntent unable to execute request.");
}
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
String errorMessage = "Location settings are inadequate, and cannot be " +
"fixed here. Fix in Settings.";
Log.e(TAG, errorMessage);
Toast.makeText(MyMap.this, errorMessage, Toast.LENGTH_LONG).show();
}
updateLocationUI();
}
});
}
@OnClick(R.id.btn_start_location_updates)
public void startLocationButtonClick() {
// Requesting ACCESS_FINE_LOCATION using Dexter library
Dexter.withActivity(this)
.withPermission(Manifest.permission.ACCESS_FINE_LOCATION)
.withListener(new PermissionListener() {
@Override
public void onPermissionGranted(PermissionGrantedResponse response) {
mRequestingLocationUpdates = true;
startLocationUpdates();
}
@Override
public void onPermissionDenied(PermissionDeniedResponse response) {
if (response.isPermanentlyDenied()) {
// open device settings when the permission is
// denied permanently
openSettings();
}
}
@Override
public void onPermissionRationaleShouldBeShown(PermissionRequest permission, PermissionToken token) {
token.continuePermissionRequest();
}
}).check();
}
@OnClick(R.id.btn_stop_location_updates)
public void stopLocationButtonClick() {
mRequestingLocationUpdates = false;
stopLocationUpdates();
}
public void stopLocationUpdates() {
// Removing location updates
mFusedLocationClient
.removeLocationUpdates(mLocationCallback)
.addOnCompleteListener(this, new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
Toast.makeText(getApplicationContext(), "Location updates stopped!", Toast.LENGTH_SHORT).show();
toggleButtons();
}
});
}
@OnClick(R.id.btn_get_last_location)
public void showLastKnownLocation() {
if (mCurrentLocation != null) {
Toast.makeText(getApplicationContext(), "Lat: " + mCurrentLocation.getLatitude()
+ ", Lng: " + mCurrentLocation.getLongitude(), Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(), "Last known location is not available!", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
// Check for the integer request code originally supplied to startResolutionForResult().
case REQUEST_CHECK_SETTINGS:
switch (resultCode) {
case Activity.RESULT_OK:
Log.e(TAG, "User agreed to make required location settings changes.");
// Nothing to do. startLocationupdates() gets called in onResume again.
break;
case Activity.RESULT_CANCELED:
Log.e(TAG, "User chose not to make required location settings changes.");
mRequestingLocationUpdates = false;
break;
}
break;
}
}
private void openSettings() {
Intent intent = new Intent();
intent.setAction(
Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
Uri uri = Uri.fromParts("package",
BuildConfig.APPLICATION_ID, null);
intent.setData(uri);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
@Override
public void onResume() {
super.onResume();
// Resuming location updates depending on button state and
// allowed permissions
if (mRequestingLocationUpdates && checkPermissions()) {
startLocationUpdates();
}
updateLocationUI();
}
private boolean checkPermissions() {
int permissionState = ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION);
return permissionState == PackageManager.PERMISSION_GRANTED;
}
@Override
protected void onPause() {
super.onPause();
if (mRequestingLocationUpdates) {
// pausing location updates
stopLocationUpdates();
}
}
public void stopTracking(View view) {
stopLocationUpdates();
startActivity(new Intent(this, Dashboard.class));
}
}