Android Open Source - bard-droid U S B Control

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License

The source code is released under:

GNU General Public License

Java Source Code

package in.co.praveenkumar.bard.io;
/*w w  w.ja va  2s .  c  o m*/
import in.co.praveenkumar.bard.graphics.Frame;

import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.IOException;

import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.hardware.usb.UsbAccessory;
import android.hardware.usb.UsbManager;
import android.os.Handler;
import android.os.Message;
import android.os.ParcelFileDescriptor;

/**
 * Configures a USB accessory and its input/output streams.
 * 
 * Call this.send to sent a byte array to the accessory Override onReceive to
 * process incoming bytes from accessory
 */

public abstract class USBControl extends Thread {

  // The permission action
  private static final String ACTION_USB_PERMISSION = "in.co.praveenkumar.bard.activities.MainActivity.USBPERMISSION";

  // An instance of accessory and manager
  private UsbAccessory mAccessory;
  private UsbManager mManager;
  private Context context;
  private Handler UIHandler;
  private Handler controlSender;
  private Thread controlListener;
  boolean connected = false;
  private ParcelFileDescriptor mFileDescriptor;
  private FileInputStream input;

  // Receiver for connect/disconnect events
  BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
      String action = intent.getAction();

      if (ACTION_USB_PERMISSION.equals(action)) {
        synchronized (this) {
          UsbAccessory accessory = (UsbAccessory) intent
              .getParcelableExtra(UsbManager.EXTRA_ACCESSORY);
          if (intent.getBooleanExtra(
              UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
            openAccessory(accessory);
          } else {

          }

        }
      } else if (UsbManager.ACTION_USB_ACCESSORY_DETACHED.equals(action)) {
        UsbAccessory accessory = (UsbAccessory) intent
            .getParcelableExtra(UsbManager.EXTRA_ACCESSORY);
        if (accessory != null && accessory.equals(mAccessory)) {
          closeAccessory();
        }
      }

    }
  };

  // Configures the usb connection
  public USBControl(Context main, Handler ui) {
    super("USBControlSender");
    UIHandler = ui;
    context = main;

    mManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
    UsbAccessory[] accessoryList = mManager.getAccessoryList();
    PendingIntent mPermissionIntent = PendingIntent.getBroadcast(context,
        0, new Intent(ACTION_USB_PERMISSION), 0);
    IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
    context.registerReceiver(mUsbReceiver, filter);

    UsbAccessory mAccessory = (accessoryList == null ? null
        : accessoryList[0]);
    if (mAccessory != null) {

      while (!mManager.hasPermission(mAccessory)) {
        mManager.requestPermission(mAccessory, mPermissionIntent);
      }
      openAccessory(mAccessory);

    }

  }

  // Send byte array over connection
  public void send(byte[] command) {
    if (controlSender != null) {
      Message msg = controlSender.obtainMessage();
      msg.obj = command;
      controlSender.sendMessage(msg);
    }
  }

  public abstract void onReceive(byte[] msg);

  public abstract void onNotify(String msg);

  public abstract void onConnected();

  public abstract void onDisconnected();

  @Override
  public void run() {
    // Listens for messages from usb accessory
    controlListener = new Thread(new Runnable() {
      boolean running = true;

      public void run() {
        while (running) {
          byte[] msg = new byte[4098];
          try {
            // Handle incoming messages
            while (input != null && input.read(msg) != -1
                && running) {
              // receive(msg);
              System.out.println("Read USB data");
              int pageIndex = (int) (msg[0] & 0x0000000ff)
                  + (int) (msg[1] << 8 & 0x0000ff00);

              System.out.println("Page index : " + pageIndex);

              // Update frame data
              int framePos = pageIndex * 4096;
              if ((framePos - (msg.length - 2)) <= Frame.FRAME_LENGTH) {
                Frame.frameBuffer.position(framePos);
                Frame.frameBuffer.put(msg, 2, msg.length - 2);
              }
            }
          } catch (final Exception e) {
            UIHandler.post(new Runnable() {
              public void run() {
                onNotify("USB Receive Failed " + e.toString()
                    + "\n");
                closeAccessory();
              }
            });
            running = false;
          }
        }
      }
    });
    controlListener.setDaemon(true);
    controlListener.setName("USBCommandListener");
    controlListener.start();
  }

  // Sets up filestreams
  private void openAccessory(UsbAccessory accessory) {
    mAccessory = accessory;
    mFileDescriptor = mManager.openAccessory(accessory);
    if (mFileDescriptor != null) {
      FileDescriptor fd = mFileDescriptor.getFileDescriptor();
      input = new FileInputStream(fd);
    }
    this.start();
    onConnected();
  }

  // Cleans up accessory
  public void closeAccessory() {

    // halt i/o
    controlSender.getLooper().quit();
    controlListener.interrupt();

    try {
      if (mFileDescriptor != null) {
        mFileDescriptor.close();
      }
    } catch (IOException e) {
    } finally {
      mFileDescriptor = null;
      mAccessory = null;
    }

    onDisconnected();
  }

  // Removes the usb receiver
  public void destroyReceiver() {
    context.unregisterReceiver(mUsbReceiver);
  }

}

Java Source Code List

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