Question

这很简单。

但我发现logcat上没有任何内容。

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_map_selection);

        LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        // Define a listener that responds to location updates
        LocationListener locationListener = new LocationListener() {

            public void onLocationChanged(Location location) {
                // Called when a new location is found by the network location provider.
                if (location != null) {
                    double longitude = location.getLongitude();
                    double latitude = location.getLatitude();

                    Log.d("MapSelectionActivity", longitude + " " + latitude);
                } else {
                    Log.d("MapSelectionActivity", "location unavailable");
                }
            }

            public void onStatusChanged(String provider, int status, Bundle extras) {
            }

            public void onProviderEnabled(String provider) {
            }

            public void onProviderDisabled(String provider) {
            }
        };

        // Register the listener with the Location Manager to receive location updates
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
    }

我确信我的手机已连接到wifi接入点，这使手机可以访问互联网。

Answer 1

检查您的申请清单。

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

试试这个。这对我有用。

public final class LocationDetector implements LocationListener {

private final Context mContext;

// flag for GPS status
public boolean isGPSEnabled = false;

// flag for network status
boolean isNetworkEnabled = false;

// flag for GPS status
public 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 LocationDetector(Context context) {
    this.mContext = context;
    getLocation();
}

/**
 * Function to get the user's current location
 * 
 * @return
 */
public Location getLocation() {
    try {
        locationManager = (LocationManager) mContext
                .getSystemService(Context.LOCATION_SERVICE);

        // getting GPS status
        isGPSEnabled = locationManager
                .isProviderEnabled(LocationManager.GPS_PROVIDER);

        // Log.v("isGPSEnabled", "=" + isGPSEnabled);

        // getting network status
        isNetworkEnabled = locationManager
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        // Log.v("isNetworkEnabled", "=" + isNetworkEnabled);

        if (isGPSEnabled == false && isNetworkEnabled == false) {
            // no network provider is enabled
        } else {
            this.canGetLocation = true;
            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(LocationDetector.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) {

}

}

获取这样的值：

    LocationDetector myloc = new LocationDetector(
                    LauncherActivity.this);
            double myLat = 0;
            double myLong = 0;
            if (myloc.canGetLocation) {

                myLat = myloc.getLatitude();
                myLong = myloc.getLongitude();

                Log.v("get location values", Double.toString(myLat)
                        + "     " + Double.toString(myLong));

            }

Answer 2

首先更改以下行：

locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);

要：

locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 5000, 0, locationListener);

喜欢它说here：

public void requestLocationUpdates (String provider, long minTime, float minDistance, LocationListener listener, Looper looper)

... minTime位置更新之间的最短时间间隔，以毫秒为单位 ...

修改我找到了这个教程here，它有一个更简单的用法：

LocationListener locationListener = new MyLocationListener(); LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 5000, 10, this.locationListener); private final class MyLocationListener implements LocationListener { @Override public void onLocationChanged(Location locFromGps) { // called when the listener is notified with a location update from the GPS } @Override public void onProviderDisabled(String provider) { // called when the GPS provider is turned off (user turning off the GPS on the phone) } @Override public void onProviderEnabled(String provider) { // called when the GPS provider is turned on (user turning on the GPS on the phone) } @Override public void onStatusChanged(String provider, int status, Bundle extras) { // called when the status of the GPS provider changes } }

为什么我不能通过NETWORK_PROVIDER获取如下位置？

2 个答案: