无法在Android中使用GPS获取位置

Question

我正在尝试使用gps service.bt而不是gettong位置获取位置的示例代码。 下面是我的代码。

   public class MainActivity extends Activity implements LocationListener{

    Location mLocation;
    LocationManager mManager;
    LocationListener mlistener;
    Geocoder mcoder;
    Context context;
    TextView txtLat;
    String lat;
    String provider;
    protected String latitude,longitude; 
    protected boolean gps_enabled,network_enabled;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    mManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
    txtLat = (TextView) findViewById(R.id.tv);
    }

    public void getMyLocation(){

            String addressString = "";

        final Geocoder gc = new Geocoder(this, Locale.getDefault());

        try
        {
            final List<Address> addresses = gc.getFromLocation(18.5203, 73.8567, 4);
            final StringBuilder sb = new StringBuilder();
            System.out.println("location..."+sb);
            if ( addresses.size() > 0 )
            {
                final Address address = addresses.get(0);
                for ( int i = 0; i < address.getMaxAddressLineIndex(); i++ )
                {
                    sb.append(address.getAddressLine(i)).append("\n");
                }
                sb.append(address.getLocality()).append("\n");
                sb.append(address.getPostalCode()).append("\n");
                sb.append(address.getCountryName());
            }
            addressString = sb.toString();
        }
        catch ( final IOException e )
        {
        }

    txtLat.setText("Your Current Position is:\n" +
             "\n" + addressString);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public void onLocationChanged(Location location) {
    getMyLocation();
}

@Override
public void onProviderDisabled(String provider) {
    // TODO Auto-generated method stub

}

@Override
public void onProviderEnabled(String provider) {
    // TODO Auto-generated method stub

}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
    // TODO Auto-generated method stub

}

 }

Answer 1

尝试以这种方式实现gps。

gps = new GPSTracker(MainActivity .this);
                 // check if GPS enabled    
                if(gps.canGetLocation()){

                    double latitude = gps.getLatitude();
                    double longitude = gps.getLongitude();
                    Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();   
                }else{
                    // can't get location
                    // GPS or Network is not enabled
                    // Ask user to enable GPS/network in settings
                    gps.showSettingsAlert();
                }

现在创建GPSTracker.java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();
    }

    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;
    }

}

更新：

如果必须使用latitude和longitude来要求locationname ，则

Geocoder gcd = new Geocoder(context, Locale.getDefault());
List<Address> addresses = gcd.getFromLocation(lat, lng, 1);
if (addresses.size() > 0) 
    System.out.println(addresses.get(0).getLocality());

在这段代码中，我只是举杯祝词您的位置，现在您可以根据需要使用它。

如果您需要任何帮助，请发表评论。

编码愉快。

Answer 2

您的代码只需要进行一些小的更改。

• 您必须实现侦听器的所有方法，以了解提供程序是否可用，设备中是否内置了该提供程序以及是否可以期望位置更新。
• 在getMyLocation()您可以使用经硬编码的纬度和经度来调用Geocoder.getFromLocation() 。 这是出于调试目的吗？
• 然后是一个新创建的空StringBuilder的System.println() 。 如果要打印出一些东西，最好使用Log.d() 。
• 最后-如果其他所有操作都有效，但您在textview中仍然没有找到地址-然后尝试Toast该地址。 发生错误的可能性较小，但由于消息在一秒钟后消失，因此您需要凝视屏幕。

我的猜测是，您的仿真器未配置GPS或没有更新-因为没有卫星，或者您根本没有等待足够长的时间来进行卫星连接。