在 Android 中使用 GPS 获取当前位置

Question

我现在正在一个项目中工作，我想使用 gps 获取用户的当前位置。我已经阅读了很多教程并尝试编写代码。该代码在模拟器中运行良好。每次我使用 DDMS 发送纬度和经度时，模拟器都会检测到。主要问题是它不适用于真实设备。虽然，我尝试过的设备可以访问互联网并且 GPS 是打开的。我已在清单文件中添加了所需的权限。

public class MainActivity extends Activity {

TextView lat;
TextView lon;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    lat=(TextView)findViewById(R.id.textView2);
    lon=(TextView)findViewById(R.id.textView4);
    LocationManager lm=(LocationManager)getSystemService(Context.LOCATION_SERVICE);
    LocationListener ll=new myLocationListener();
    lm.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0, ll);
}

@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;
}
   class myLocationListener implements LocationListener{

@Override
public void onLocationChanged(Location location) {
    // TODO Auto-generated method stub
    if(location!=null){
        double pLat=location.getLatitude();
        double pLong=location.getLongitude();
        lat.setText(Double.toString(pLat));
        lon.setText(Double.toString(pLong));
    }
}

@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

}

 }
}

清单文件中的权限

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

我需要帮助。

Answer 1

GPSTracker gps = new GPSTracker(this);
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();

使用此 GPS 服务：

import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;

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;
                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) {
        }
        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 DialogHelp Title
        alertDialog.setTitle("GPS is settings");

        // Setting DialogHelp 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) {
        float bestAccuracy = -1f;
        if (location.getAccuracy() != 0.0f
            && (location.getAccuracy() < bestAccuracy) || bestAccuracy == -1f) {
                locationManager.removeUpdates(this);
        }
        bestAccuracy = location.getAccuracy();
    }

    @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;
    }

    public float getAccurecy()
    {
        return location.getAccuracy();
    }

}

Answer 2

试试这样。您应该记住，本地化需要启动 GPS，并且需要一些时间。在该课程中，我会延迟一些时间来触发定位内容以获得结果，因为 GPS 组件应该有时间启动。

public class MyBestLocation {
    LocationListener locationListenerGps = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {
            locationResult.gotLocation(location);
            lm.removeUpdates(this);
            lm.removeUpdates(locationListenerNetwork);
        }

        @Override
        public void onProviderDisabled(String provider) {
        }

        @Override
        public void onProviderEnabled(String provider) {
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
        }
    };
    LocationListener locationListenerNetwork = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {
            locationResult.gotLocation(location);
            lm.removeUpdates(this);
            lm.removeUpdates(locationListenerGps);
        }

        @Override
        public void onProviderDisabled(String provider) {
        }

        @Override
        public void onProviderEnabled(String provider) {
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
        }
    };
    //delay in seconds
    private int DELAY = 1;
    private Timer timer1;
    private LocationManager lm;
    private LocationResult locationResult;
    private boolean gps_enabled = false;
    private boolean network_enabled = false;
    private ScheduledExecutorService scheduler;
    private ScheduledFuture scheduledFuture;

    public boolean getLocation(Context context, LocationResult result) {
        // 
        locationResult = result;
        if (lm == null)
            lm = (LocationManager) context
                    .getSystemService(Context.LOCATION_SERVICE);

        // checking weather providers are aviliable
        try {
            gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
        } catch (Exception ex) {
        }
        try {
            network_enabled = lm
                    .isProviderEnabled(LocationManager.NETWORK_PROVIDER);
        } catch (Exception ex) {
        }

        // 
        if (!gps_enabled && !network_enabled)
            return false;

        if (gps_enabled)
            lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0,
                    locationListenerGps);
        if (network_enabled)
            lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0,
                    locationListenerNetwork);
        //----------------------
       // async executor method upgrade
        timer1 = new Timer();
        timer1.schedule(new GetLastLocation(), DELAY*2000);
       // ----------------

        // 
       /* scheduler = Executors.newSingleThreadScheduledExecutor();
        scheduler.schedule(new GetLastLocation(), DELAY, TimeUnit.SECONDS);*/
        return true;
    }

    // Timer for the latest location

    public static abstract class LocationResult {
        public abstract void gotLocation(Location location);
    }

    /**
     * 
     *
     * @author rafik991
     */
    class GetLastLocation extends TimerTask {
        @Override
        public void run() {


            lm.removeUpdates(locationListenerGps);
            lm.removeUpdates(locationListenerNetwork);

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

            // if there are both values use the latest one
            if (gps_loc != null && net_loc != null) {
                if (gps_loc.getTime() > net_loc.getTime())
                    locationResult.gotLocation(gps_loc);
                else
                    locationResult.gotLocation(net_loc);

                return;
            }

            if (gps_loc != null) {
                locationResult.gotLocation(gps_loc);

                return;
            }
            if (net_loc != null) {
                locationResult.gotLocation(net_loc);

                return;
            }
//          locationResult.gotLocation(null);
        }

    }

}