Android - 如何在新 API 中请求位置更新？

Question

我在谷歌的新位置 API 上玩了一下（获取纬度和经度值）：

private void getLastLocation(){
    FusedLocationProviderClient mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
    try {
        mFusedLocationClient.getLastLocation().addOnSuccessListener(new OnSuccessListener<Location>() {
            @Override
            public void onSuccess(Location location) {
                if (location != null) {
                    double latitude = location.getLatitude();
                    double longitude = location.getLongitude();
                    Toast.makeText(getApplicationContext(), String.valueOf(latitude) + "/" + String.valueOf(longitude), Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(getApplicationContext(), "Cannot get location", Toast.LENGTH_LONG).show();
                }
            }
        })
                .addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        Log.d("LocationFetch", "Error trying to get last GPS location");
                        e.printStackTrace();
                    }
                });
    } catch (SecurityException e){
        Log.d("LocationFetch", "Permission missing");
    }
}

当我第一次测试这段代码时，location 总是返回 null。然而，在打开 Instagram（它在我的手机上进行了位置更新 - 地理图标短暂出现）后，location 正在返回我的相关经度和纬度值。

如何使用新 API 在我的应用上请求位置更新，以防止 location 为空或检索非常旧的位置？ （getLastLocation()不够，可能LocationRequest？）

值得注意的是，我不希望间隔更新，我希望它在调用一次时在 Android 服务中发生。

Answer 1

这对我有用。基于Official docs，每 10 秒更新一次 Toast 并显示您的位置：

private FusedLocationProviderClient fusedLocationClient;
private LocationRequest locationRequest;
private LocationCallback locationCallback;



@Override
protected void onResume() {
    super.onResume();
    startLocationUpdates();

}

private void startLocationUpdates() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    Activity#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for Activity#requestPermissions for more details.
            return;
        }
    }
    fusedLocationClient.requestLocationUpdates(locationRequest,
            locationCallback,
            Looper.getMainLooper());
}

@Override
protected void onPause() {
    super.onPause();
    stopLocationUpdates();
}

private void stopLocationUpdates() {
    fusedLocationClient.removeLocationUpdates(locationCallback);
}

在 onCreate 方法中添加如下代码：

    fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
    locationRequest = LocationRequest.create();
    locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    locationRequest.setInterval(2*5000);

    locationCallback=new LocationCallback(){
        @Override
        public void onLocationResult(LocationResult locationResult) {
            if (locationResult == null) {
                return;
            }
            for (Location location : locationResult.getLocations()) {
               // if (location != null) {


                    String Lat = String.valueOf(location.getLatitude());
                    String Lon = String.valueOf(location.getLongitude());

                    Toast.makeText(getApplicationContext(), Lat + " - " + Lon, Toast.LENGTH_SHORT).show();
            //    }
            }
        }
    };

Answer 2

首先在你的build.gradle文件中添加这个实现

implementation 'com.google.android.gms:play-services-location:11.2.0'//include the latest version of play services

在您的活动或片段中实现（实现LocationListener），然后实现其功能，然后

在您的onCreate() getLocation(); 中调用此方法 然后在这个函数中添加这些行

protected void getLocation() {
    if (isLocationEnabled(MainActivity.this)) {
        locationManager = (LocationManager)  this.getSystemService(Context.LOCATION_SERVICE);
        criteria = new Criteria();
        bestProvider = String.valueOf(locationManager.getBestProvider(criteria, true)).toString();

        //You can still do this if you like, you might get lucky:
        Location location = locationManager.getLastKnownLocation(bestProvider);
        if (location != null) {
            Log.e("TAG", "GPS is on");
            latitude = location.getLatitude();
            longitude = location.getLongitude();
            Toast.makeText(MainActivity.this, "latitude:" + latitude + " longitude:" + longitude, Toast.LENGTH_SHORT).show();
            searchNearestPlace(voice2text);
        }
        else{
            //This is what you need:
            locationManager.requestLocationUpdates(bestProvider, 1000, 0, this);
        }
    }
    else
    {
        //prompt user to enable location....
        //.................
    }
}

之后在您的onLocationChanged(Location location) 添加这几行代码

@Override
public void onLocationChanged(Location location) {
    //Hey, a non null location! Sweet!

    //remove location callback:
    locationManager.removeUpdates(this);

    //open the map:
    latitude = location.getLatitude();
    longitude = location.getLongitude();
    Toast.makeText(MainActivity.this, "latitude:" + latitude + " longitude:" + longitude, Toast.LENGTH_SHORT).show();
    searchNearestPlace(voice2text);
}

你准备好了！！！！ 干杯快乐编码

Answer 3

使用这个类

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();
}

@SuppressLint("MissingPermission")
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;
}
} 

在Ur Activity类中使用这个方法

  double latitude, longitude;
  private void getLocation() {
    GPSTracker gps = new GPSTracker(this);
    if (gps.canGetLocation()) {

        latitude = gps.getLatitude();
        longitude = gps.getLongitude();
        Log.d("lat", "" + latitude);
        Log.d("long", "" + longitude);


    } else {
        // can't get location
        // GPS or Network is not enabled
        // Ask user to enable GPS/network in settings
        gps.showSettingsAlert();
    }

Answer 4

试试这个代码。

在渐变中

implementation 'com.google.android.gms:play-services-location:16.0.0'

在代码中

 private void turnGPSOn() {
    LocationRequest mLocationRequest = LocationRequest.create()
            .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
            .setInterval(10 * 1000)
            .setFastestInterval(1 * 1000);

    LocationSettingsRequest.Builder settingsBuilder = new LocationSettingsRequest.Builder()
            .addLocationRequest(mLocationRequest);
    settingsBuilder.setAlwaysShow(true);

    Task<LocationSettingsResponse> result = LocationServices.getSettingsClient(this)
            .checkLocationSettings(settingsBuilder.build());

    result.addOnCompleteListener(new OnCompleteListener<LocationSettingsResponse>() {
        @Override
        public void onComplete(@NonNull Task<LocationSettingsResponse> task) {
            try {
                LocationSettingsResponse response =
                        task.getResult(ApiException.class);

                if (gps.canGetLocation()) {
                    lat = String.valueOf(gps.getLatitude());
                    lon = String.valueOf(gps.getLongitude());
                }

            } catch (ApiException ex) {
                switch (ex.getStatusCode()) {
                    case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
                        try {
                            ResolvableApiException resolvableApiException =
                                    (ResolvableApiException) ex;
                            resolvableApiException
                                    .startResolutionForResult(SignupActivity.this,
                                            REQUEST_CHECK_SETTINGS);
                        } catch (IntentSender.SendIntentException e) {

                        }
                        break;
                    case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:

                        break;
                }
            }
        }
    });
}