ExternGnss/app/src/main/java/hendrikschutter/com/externgnss/SerialUSB.java

package hendrikschutter.com.externgnss;

import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbManager;
import android.util.Log;

import com.hoho.android.usbserial.driver.UsbSerialDriver;
import com.hoho.android.usbserial.driver.UsbSerialPort;
import com.hoho.android.usbserial.driver.UsbSerialProber;
import com.hoho.android.usbserial.util.SerialInputOutputManager;

import java.io.IOException;

public class SerialUSB implements SerialInputOutputManager.Listener{

    private MainActivity mainActivity = null;

    private enum UsbPermission { Unknown, Requested, Granted, Denied }

    private static final String INTENT_ACTION_GRANT_USB = BuildConfig.APPLICATION_ID + ".GRANT_USB";
    private static final int WRITE_WAIT_MILLIS = 2000;
    private static final int READ_WAIT_MILLIS = 2000;

    private int deviceId, portNum, baudRate;
    private boolean withIoManager;

    private BroadcastReceiver broadcastReceiver = null;
    //private final Handler mainLooper;
    //private TextView receiveText;
    //private ControlLines controlLines;

    private SerialInputOutputManager usbIoManager;
    private UsbSerialPort usbSerialPort;
    private UsbPermission usbPermission = UsbPermission.Unknown;
    private boolean connected = false;

    public SerialUSB(MainActivity mainActivity){
        this.mainActivity = mainActivity;

        // Find all available drivers from attached devices.
        UsbManager usbManager = (UsbManager) this.mainActivity.getSystemService(Context.USB_SERVICE);
        UsbSerialProber usbDefaultProber = UsbSerialProber.getDefaultProber();

       if (usbManager.getDeviceList().values().size() > 0){
           UsbDevice device = (UsbDevice) usbManager.getDeviceList().values().toArray()[0];
           UsbSerialDriver driver = usbDefaultProber.probeDevice(device);
           if(driver == null) {
               Log.i("SerialUSB", "driver is null");
           }
           if(driver != null) {
               Log.i("SerialUSB", "ExternGNSS: device/driver found!");
                this.deviceId = device.getDeviceId();
                this.portNum = 0;
                this.baudRate = 9600;
                this.withIoManager = true;
           }
       }


        broadcastReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                if(INTENT_ACTION_GRANT_USB.equals(intent.getAction())) {
                    usbPermission = intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false) ? UsbPermission.Granted : UsbPermission.Denied;
                    connect();
                } else {
                    Log.i("SerialUSB", "USB permissions are not set");
                }
            }
        };
        connect();
       this.mainActivity.registerReceiver(broadcastReceiver, new IntentFilter(INTENT_ACTION_GRANT_USB));
    }

    private void connect() {
        Log.i("connect", "starting to connect ...");
        UsbDevice device = null;
        UsbManager usbManager = (UsbManager) this.mainActivity.getSystemService(Context.USB_SERVICE);
        for(UsbDevice v : usbManager.getDeviceList().values())
            if(v.getDeviceId() == deviceId)
                device = v;
        if(device == null) {
            Log.i("connect", "connection failed: device not found");
            return;
        }
        UsbSerialDriver driver = UsbSerialProber.getDefaultProber().probeDevice(device);
        /*
        if(driver == null) {
            driver = CustomProber.getCustomProber().probeDevice(device);
        }
         */
        if(driver == null) {
            Log.i("connect", "connection failed: no driver for device");
            return;
        }
        if(driver.getPorts().size() < portNum) {
            Log.i("connect", "connection failed: not enough ports at device");
            return;
        }
        usbSerialPort = driver.getPorts().get(portNum);
        UsbDeviceConnection usbConnection = usbManager.openDevice(driver.getDevice());
        if(usbConnection == null && usbPermission == UsbPermission.Unknown && !usbManager.hasPermission(driver.getDevice())) {
            usbPermission = UsbPermission.Requested;
            PendingIntent usbPermissionIntent = PendingIntent.getBroadcast(this.mainActivity, 0, new Intent(INTENT_ACTION_GRANT_USB), 0);
            usbManager.requestPermission(driver.getDevice(), usbPermissionIntent);
            return;
        }
        if(usbConnection == null) {
            if (!usbManager.hasPermission(driver.getDevice()))
                Log.i("connect", "connection failed: permission denied");
            else
                Log.i("connect", "connection failed: open failed");
            return;
        }

        try {
            usbSerialPort.open(usbConnection);
            usbSerialPort.setParameters(baudRate, 8, 1, UsbSerialPort.PARITY_NONE);
            if(withIoManager) {
                usbIoManager = new SerialInputOutputManager(usbSerialPort, this);
                usbIoManager.start();
            }

            Log.i("connect", "connected");
            connected = true;
            //controlLines.start();
        } catch (Exception e) {
            Log.i("connect", "connection failed: " + e.getMessage());
            disconnect();
        }
    }

    private void disconnect() {
        connected = false;
        //controlLines.stop();
        if(usbIoManager != null) {
            usbIoManager.setListener(null);
            usbIoManager.stop();
        }
        usbIoManager = null;
        try {
            usbSerialPort.close();
        } catch (IOException ignored) {}
        usbSerialPort = null;
    }

    @Override
    public void onNewData(byte[] data) {
        Log.i("connect", "received data: " + data.length);
    }

    @Override
    public void onRunError(Exception e) {
        Log.e("SerialUSB", "runtime error: " + e.getMessage());
        this.disconnect();
    }
}