How do I get the NMEA data from a serial GPS connected to my android device?

Question

I am working on a project where I have to connect my android device to a GPS with usb. I can't figure out how I can get the data out of my GPS and I do not want to use the device it's internall GPS because I need to be pretty accurate. I have read the tutorial on the android website and I have tried to work with it but I still do not understand how I have to make connection to the GPS. Here is my code.

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbManager;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;

import java.util.HashMap;


public class MainActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}


UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);

HashMap<String, UsbDevice> deviceList = manager.getDeviceList();
UsbDevice device = deviceList.get("deviceName");


private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if(ACTION_USB_PERMISSION.equals(action)) {
            synchronized (this) {
                UsbDevice device =    (UsbDevice)intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                if  (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)){
                    if(device != null){
                        //roep hier de method aan om communicatie met he apparaat te maken
                    }
                }
                else{
                    Log.d(TAG, "permission denied for device " + device);
                }
            }
        }
    }
}
}

Answer 1

You might want to give this a shot: http://code.google.com/p/usb-serial-for-android/ . Captures all serial data, does not require rooting. You would need to use Service. Let us know if you need more help. I have done this before, not on Android though.