Cek GPS

 private void cekGPS() {
    try {
        // pengecekan GPS hidup / tidak
        LocationManager manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        if (!manager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("Info");
            builder.setMessage("Anda akan mengaktifkan GPS?");
            builder.setPositiveButton("Ya",new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub
                    Intent intent = new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                    startActivity(intent);
                }
            });
            builder.setNegativeButton("Tidak",new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub
                    dialog.dismiss();
                }
            });
            builder.create().show();
        }
    } catch (Exception e) {

    }
    int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());

    // menampilkan status google play service
    if (status != ConnectionResult.SUCCESS) {
        int requestCode = 10;
        Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this,requestCode);
            dialog.show();
    } else {
    // google play service tersedia
        try {
            LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

            // membuat kriteria untuk menampung provider
            Criteria criteria = new Criteria();

            // mencari provider terbaik
            String provider = locationManager.getBestProvider(criteria, true);

            // mendapatkan lokasi terakhir
            Location location = locationManager.getLastKnownLocation(provider);

            if (location != null) {
                onLocationChanged(location);
            }

            locationManager.requestLocationUpdates(provider, 5000, 0, this);
        } catch (Exception e) {

        }
    }
}