我正在尝试使用FusedLocationProviderClient来获得后台服务，但是它无法在后台运行。我如何使其在后台工作？
如果这不是最好的方法，请您给我最好的方法。
这是我的主要活动
package com.professionalandroid.apps.whereami;
import android.Manifest;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Intent;
import android.content.IntentSender;
import android.location.Location;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.ApiException;
import com.google.android.gms.common.api.CommonStatusCodes;
import com.google.android.gms.common.api.ResolvableApiException;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.location.LocationSettingsRequest;
import com.google.android.gms.location.LocationSettingsResponse;
import com.google.android.gms.location.LocationSettingsStates;
import com.google.android.gms.location.LocationSettingsStatusCodes;
import com.google.android.gms.location.SettingsClient;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import static android.Manifest.permission.ACCESS_COARSE_LOCATION;
import static android.Manifest.permission.ACCESS_FINE_LOCATION;
import static
android.support.v4.content.PermissionChecker.PERMISSION_GRANTED;
public class WhereAmIActivity extends AppCompatActivity {
public static final String TAG = "WhereAmIActivity";
private static final String ERROR_MSG = "Google Play services are
unavailable.";
private static final int LOCATION_PERMISSION_REQUEST = 1;
private static final int REQUEST_CHECK_SETTINGS = 2;
private TextView mTextView;
private LocationRequest mLocationRequest;
LocationCallback mLocationCallback = new LocationCallback() {
@Override
public void onLocationResult(LocationResult locationResult) {
Location location = locationResult.getLastLocation();
if (location != null) {
updateTextView(location);
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_where_am_i);
mTextView = findViewById(R.id.myLocationText);
GoogleApiAvailability availability = GoogleApiAvailability.getInstance();
int result = availability.isGooglePlayServicesAvailable(this);
if (result != ConnectionResult.SUCCESS) {
if (!availability.isUserResolvableError(result)) {
Toast.makeText(this, ERROR_MSG, Toast.LENGTH_LONG).show();
}
}
mLocationRequest = new LocationRequest()
.setInterval(5000)
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
}
@Override
protected void onStart() {
super.onStart();
// Check if we have permission to access high accuracy fine location.
int permission = ActivityCompat.checkSelfPermission(this,
ACCESS_FINE_LOCATION);
// If permission is granted, fetch the last location.
if (permission == PERMISSION_GRANTED) {
getLastLocation();
} else {
// If permission has not been granted, request permission.
ActivityCompat.requestPermissions(this,
new String[]{ACCESS_FINE_LOCATION},
LOCATION_PERMISSION_REQUEST);
}
// Check of the location settings are compatible with our Location
Request.
LocationSettingsRequest.Builder builder =
new LocationSettingsRequest.Builder()
.addLocationRequest(mLocationRequest);
SettingsClient client = LocationServices.getSettingsClient(this);
Task<LocationSettingsResponse> task =
client.checkLocationSettings(builder.build());
task.addOnSuccessListener(this,
new OnSuccessListener<LocationSettingsResponse>() {
@Override
public void onSuccess(LocationSettingsResponse
locationSettingsResponse) {
// Location settings satisfy the requirements of the Location
Request.
// Request location updates.
requestLocationUpdates();
}
});
task.addOnFailureListener(this, new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
// Extract the status code for the failure from within the Exception.
int statusCode = ((ApiException) e).getStatusCode();
switch (statusCode) {
case CommonStatusCodes.RESOLUTION_REQUIRED:
try {
// Display a user dialog to resolve the location settings
// issue.
ResolvableApiException resolvable = (ResolvableApiException) e;
resolvable.startResolutionForResult(WhereAmIActivity.this,
REQUEST_CHECK_SETTINGS);
} catch (IntentSender.SendIntentException sendEx) {
Log.e(TAG, "Location Settings resolution failed.", sendEx);
}
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
// Location settings issues can't be resolved by user.
// Request location updates anyway.
Log.d(TAG, "Location Settings can't be resolved.");
requestLocationUpdates();
break;
}
}
});
}
@Override
public void onRequestPermissionsResult(int requestCode,
@NonNull String[] permissions,
@NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == LOCATION_PERMISSION_REQUEST) {
if (grantResults[0] != PERMISSION_GRANTED)
Toast.makeText(this, "Location Permission Denied",
Toast.LENGTH_LONG).show();
}
}
private void getLastLocation() {
FusedLocationProviderClient fusedLocationClient;
fusedLocationClient =
LocationServices.getFusedLocationProviderClient(this);
LocationRequest locationRequest = new LocationRequest()
.setInterval(3000)
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
final int locationRC = 0;
int flags = PendingIntent.FLAG_UPDATE_CURRENT;
Intent intent = new Intent(this, MyLocationUpdateReciever.class);
intent.setAction("com.Android.custom_TUT");
PendingIntent pendingIntent = PendingIntent.getBroadcast(this,
locationRC,
intent, flags);
if (ActivityCompat.checkSelfPermission(this, ACCESS_FINE_LOCATION)
== PERMISSION_GRANTED ||
ActivityCompat.checkSelfPermission(this, ACCESS_COARSE_LOCATION)
== PERMISSION_GRANTED) {
fusedLocationClient.
requestLocationUpdates(locationRequest,pendingIntent);
}
}
private void updateTextView(Location location) {
String latLongString = "No location found";
if (location != null) {
double lat = location.getLatitude();
double lng = location.getLongitude();
latLongString = "Lat:" + lat + "\nLong:" + lng;
Toast.makeText(WhereAmIActivity.this, ""+lat+""+lng,
Toast.LENGTH_SHORT).show();
}
mTextView.setText(latLongString);
}
private void requestLocationUpdates() {
FusedLocationProviderClient fusedLocationClient;
fusedLocationClient =
LocationServices.getFusedLocationProviderClient(this);
LocationRequest locationRequest = new LocationRequest()
.setInterval(3000)
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
final int locationRC = 0;
int flags = PendingIntent.FLAG_UPDATE_CURRENT;
Intent intent = new Intent(this, MyLocationUpdateReciever.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this,
locationRC,
intent, flags);
if (ActivityCompat.checkSelfPermission(this, ACCESS_FINE_LOCATION)
== PERMISSION_GRANTED ||
ActivityCompat.checkSelfPermission(this, ACCESS_COARSE_LOCATION)
== PERMISSION_GRANTED) {
fusedLocationClient
.requestLocationUpdates(locationRequest,pendingIntent);
}
}
@Override
protected void onActivityResult(int requestCode,
int resultCode,Intent data){
final LocationSettingsStates states =
LocationSettingsStates.fromIntent(data);
if (requestCode == REQUEST_CHECK_SETTINGS) {
switch (resultCode) {
case Activity.RESULT_OK:
// Requested changes made, request location updates.
requestLocationUpdates();
break;
case Activity.RESULT_CANCELED:
// Requested changes were NOT made.
Log.d(TAG, "Requested settings changes declined by user.");
// Check if any location services are available, and if so
// request location updates.
if (states.isLocationUsable())
requestLocationUpdates();
else
Log.d(TAG, "No location services available.");
break;
default: break;
}
}
}
}
这是广播接收器类
package com.professionalandroid.apps.whereami;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.util.Log;
import android.widget.Toast;
import com.google.android.gms.location.LocationResult;
public class MyLocationUpdateReciever extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if(LocationResult.hasResult(intent)){
LocationResult locationResult =
LocationResult.extractResult(intent);
for(Location location: locationResult.getLocations()){
Toast.makeText(context, "longitude: =
"+location.getLongitude()
+"latitude: = "+location.getLatitude(),
Toast.LENGTH_SHORT).show();
Log.d("DSK_OPER","backgroud");
}
}
}
}
我还在清单中添加了用于精确定位和课程定位的权限，并且还添加了服务类。