如何在Android中锁定屏幕时长按电源按钮启用GPS？

Question

我正在开发一个应用程序，当用户在设备实际锁定为模式/屏幕锁定模式时长按电源键按钮时，发送用户在所选联系人号码上的当前位置。那么如何启用 GPS 以使其自动启用并获取当前的经度和纬度。

Answer 1

首先，您需要注意按键，并且有一些很好的信息here。

这是一个获取经度和纬度的例子：

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;

    boolean canGetLocation = false;

    Location location;
    double latitude;
    double longitude;

    //The minimum distance to change updates in metters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; //10 metters

    //The minimum time beetwen 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);
                        updateGPSCoordinates();
                    }
                }

                //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);
                            updateGPSCoordinates();
                        }
                    }
                }
            }
        }
        catch (Exception e)
        {
            //e.printStackTrace();
            Log.e("Error : Location", "Impossible to connect to LocationManager", e);
        }

        return location;
    }

    public void updateGPSCoordinates()
    {
        if (location != null)
        {
            latitude = location.getLatitude();
            longitude = location.getLongitude();
        }
    }

    /**
     * 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;
    }

    /**
     * Function to get longitude
     */
    public double getLongitude()
    {
        if (location != null)
        {
            longitude = location.getLongitude();
        }

        return longitude;
    }

    /**
     * Function to check GPS/wifi enabled
     */
    public boolean canGetLocation()
    {
        return this.canGetLocation;
    }

    /**
     * Function to show settings alert dialog
     */
    public void showSettingsAlert()
    {
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

        //Setting Dialog Title
        alertDialog.setTitle(R.string.GPSAlertDialogTitle);

        //Setting Dialog Message
        alertDialog.setMessage(R.string.GPSAlertDialogMessage);

        //On Pressing Setting button
        alertDialog.setPositiveButton(R.string.settings, new DialogInterface.OnClickListener() 
        {   
            @Override
            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(R.string.cancel, new DialogInterface.OnClickListener() 
        {   
            @Override
            public void onClick(DialogInterface dialog, int which) 
            {
                dialog.cancel();
            }
        });

        alertDialog.show();
    }

    /**
     * Get list of address by latitude and longitude
     * @return null or List<Address>
     */
    public List<Address> getGeocoderAddress(Context context)
    {
        if (location != null)
        {
            Geocoder geocoder = new Geocoder(context, Locale.ENGLISH);
            try 
            {
                List<Address> addresses = geocoder.getFromLocation(latitude, longitude, 1);
                return addresses;
            } 
            catch (IOException e) 
            {
                //e.printStackTrace();
                Log.e("Error : Geocoder", "Impossible to connect to Geocoder", e);
            }
        }

        return null;
    }

    /**
     * Try to get AddressLine
     * @return null or addressLine
     */
    public String getAddressLine(Context context)
    {
        List<Address> addresses = getGeocoderAddress(context);
        if (addresses != null && addresses.size() > 0)
        {
            Address address = addresses.get(0);
            String addressLine = address.getAddressLine(0);

            return addressLine;
        }
        else
        {
            return null;
        }
    }

    /**
     * Try to get Locality
     * @return null or locality
     */
    public String getLocality(Context context)
    {
        List<Address> addresses = getGeocoderAddress(context);
        if (addresses != null && addresses.size() > 0)
        {
            Address address = addresses.get(0);
            String locality = address.getLocality();

            return locality;
        }
        else
        {
            return null;
        }
    }

    /**
     * Try to get Postal Code
     * @return null or postalCode
     */
    public String getPostalCode(Context context)
    {
        List<Address> addresses = getGeocoderAddress(context);
        if (addresses != null && addresses.size() > 0)
        {
            Address address = addresses.get(0);
            String postalCode = address.getPostalCode();

            return postalCode;
        }
        else
        {
            return null;
        }
    }

    /**
     * Try to get CountryName
     * @return null or postalCode
     */
    public String getCountryName(Context context)
    {
        List<Address> addresses = getGeocoderAddress(context);
        if (addresses != null && addresses.size() > 0)
        {
            Address address = addresses.get(0);
            String countryName = address.getCountryName();

            return countryName;
        }
        else
        {
            return null;
        }
    }

    @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 intent) 
    {
        return null;
    }
}