Android位置管理器,获取GPS位置,如果没有GPS,则转到网络提供商位置

Question

我使用下面给出的代码来获取位置:

public Location getLocation() {
        try {
            mLocationManager = (LocationManager) context.getSystemService(LOCATION_SERVICE);

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

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

            if (!isGPSEnabled && !isNetworkEnabled) {
                // no network provider is enabled
            } else {
                // First get location from Network Provider
                if (isNetworkEnabled) {
                    mLocationManager.requestLocationUpdates( LocationManager.NETWORK_PROVIDER,  MIN_TIME_BW_UPDATES,  MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("Network", "Network");
                    if (mLocationManager != null) {
                        location = mLocationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                        if (location != null) {
                            lat = location.getLatitude();
                            lng = location.getLongitude();
                        }
                    }
                }
                //get the location by gps
                if (isGPSEnabled) {
                    if (location == null) {
                        mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,MIN_TIME_BW_UPDATES,MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                        Log.d("GPS Enabled", "GPS Enabled");
                        if (mLocationManager != null) {location = mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                            if (location != null) {
                                lat = location.getLatitude();
                                lng = location.getLongitude();
                            }
                        }
                    }
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        return location;
    }

它工作正常,但我想首先获得GPS位置,如果它不可用,位置管理员应该查询网络提供商,我遇到了麻烦.

请推荐我这样做的好方法.

Answer 1

你说你首先需要GPS位置,但你所做的是首先从网络提供商那里获得位置,然后从GPS获得位置.如果两者都可用,这将从网络和GPS获得位置.你可以做的是,在if..else if块中写下这些案例.相近-

if( !isGPSEnabled && !isNetworkEnabled) {

// Can't get location by any way

} else {

    if(isGPSEnabled) {

    // get location from GPS

    } else if(isNetworkEnabled) {

    // get location from Network Provider

    }
}

因此,这将首先从GPS获取位置(如果可用),否则它将尝试从网络提供商获取位置.

编辑:

为了让它更好,我会发布一个片段.考虑它在try-catch:

boolean gps_enabled = false;
boolean network_enabled = false;

LocationManager lm = (LocationManager) mCtx
                .getSystemService(Context.LOCATION_SERVICE);

gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
network_enabled = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);

Location net_loc = null, gps_loc = null, finalLoc = null;

if (gps_enabled)
    gps_loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (network_enabled)
    net_loc = lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

if (gps_loc != null && net_loc != null) {

    //smaller the number more accurate result will
    if (gps_loc.getAccuracy() > net_loc.getAccuracy()) 
        finalLoc = net_loc;
    else
        finalLoc = gps_loc;

        // I used this just to get an idea (if both avail, its upto you which you want to take as I've taken location with more accuracy)

} else {

    if (gps_loc != null) {
        finalLoc = gps_loc;
    } else if (net_loc != null) {
        finalLoc = net_loc;
    }
}

现在,你检查finalLoc的null,如果不是那么return它.您可以在返回所需(finalLoc)位置的函数中编写上述代码.我认为这可能有所帮助.

Answer 2

建议的方法是使用LocationClient:

首先,定义位置更新间隔值.根据您的需要进行调整.

private static final int MILLISECONDS_PER_SECOND = 1000;
private static final long UPDATE_INTERVAL = MILLISECONDS_PER_SECOND * UPDATE_INTERVAL_IN_SECONDS;
private static final int FASTEST_INTERVAL_IN_SECONDS = 1;
private static final long FASTEST_INTERVAL = MILLISECONDS_PER_SECOND * FASTEST_INTERVAL_IN_SECONDS;

让你的Activity落实GooglePlayServicesClient.ConnectionCallbacks,GooglePlayServicesClient.OnConnectionFailedListener以及LocationListener.

public class LocationActivity extends Activity implements 
GooglePlayServicesClient.ConnectionCallbacks, GooglePlayServicesClient.OnConnectionFailedListener, LocationListener {}

然后,LocationClient在onCreate()你的方法中设置一个Activity:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mLocationClient = new LocationClient(this, this, this);

    mLocationRequest = LocationRequest.create();
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    mLocationRequest.setInterval(UPDATE_INTERVAL);
    mLocationRequest.setFastestInterval(FASTEST_INTERVAL);
}

添加所需的方法到您的Activity; onConnected()是LocationClient连接时调用的方法.onLocationChanged()是您将检索最新位置的地方.

@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
    Log.w(TAG, "Location client connection failed");
}

@Override
public void onConnected(Bundle dataBundle) {
    Log.d(TAG, "Location client connected");
    mLocationClient.requestLocationUpdates(mLocationRequest, this); 
}

@Override
public void onDisconnected() {
    Log.d(TAG, "Location client disconnected");
}

@Override
public void onLocationChanged(Location location) {
    if (location != null) {
        Log.d(TAG, "Updated Location: " + Double.toString(location.getLatitude()) + "," + Double.toString(location.getLongitude()));
    } else {
        Log.d(TAG, "Updated location NULL");
    } 
}     

确保连接/断开连接,LocationClient以便在绝对必要时仅使用额外的电池,因此GPS无法无限期运行.在LocationClient必须连接,以便从中获取数据.

public void onResume() {
    super.onResume();
    mLocationClient.connect();
}

public void onStop() {
    if (mLocationClient.isConnected()) {
        mLocationClient.removeLocationUpdates(this);
    }
    mLocationClient.disconnect();
    super.onStop();
}

获取用户的位置.首先尝试使用LocationClient; 如果失败了,请回到LocationManager.

public Location getLocation() {
    if (mLocationClient != null && mLocationClient.isConnected()) {
        return mLocationClient.getLastLocation();
    } else {
        LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        if (locationManager != null) {
            Location lastKnownLocationGPS = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
            if (lastKnownLocationGPS != null) {
                return lastKnownLocationGPS;
            } else {
                return locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
            }
        } else {
            return null;
        }
    }
}