UsbTest.java

package greendrm.android.usbtest;

import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;

import com.android.future.usb.UsbAccessory;
import com.android.future.usb.UsbManager;

import android.app.Activity;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.ParcelFileDescriptor;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class UsbTest extends Activity {
	private static final boolean DEBUG = true;
	private static final String TAG = "USB"; 
	
	private static final String ACTION_USB_PERMISSION = "greendrm.android.usbtest.USBPERMISSION";
	private UsbAccessory mAccessory = null;
	private Button mBtSend = null;
	
	private ParcelFileDescriptor mFd = null;
	private FileOutputStream mFout = null;
	
	private UsbManager mUsbManager;
	private PendingIntent mPermissionIntent = null;
	private boolean mPermissionRequestPending;
	
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        if (DEBUG) Log.d(TAG, "onCreate()");
        
        mUsbManager = UsbManager.getInstance(this);
        mPermissionIntent = PendingIntent.getBroadcast(this, 0, 
        		new Intent(ACTION_USB_PERMISSION),0);
        
        IntentFilter i = new IntentFilter();
        //i.addAction(UsbManager.ACTION_USB_ACCESSORY_ATTACHED);
        i.addAction(UsbManager.ACTION_USB_ACCESSORY_DETACHED);
        i.addAction(ACTION_USB_PERMISSION);
        registerReceiver(mUsbReceiver,i);
        
        if (getLastNonConfigurationInstance() != null) {
        	mAccessory = (UsbAccessory)getLastNonConfigurationInstance();
        	openAccessory(mAccessory);
        }
        
        mBtSend = (Button)(findViewById(R.id.btSebd));
        mBtSend.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View v) {
				String s = ((EditText)findViewById(R.id.editText1)).getText().toString();
				queueWrite(s);
			}
		});
    }
    
    @Override
    public Object onRetainNonConfigurationInstance() {
    	if (DEBUG) Log.d(TAG, "onRetainNonConfigurationInstance()");
    	
    	if (mAccessory != null) {
    		return mAccessory;
    	}
    	else {
    		return super.onRetainNonConfigurationInstance();
    	}
    }
    
    @Override
    public void onResume() {
    	if (DEBUG) Log.d(TAG, "onResume()");
    	
    	super.onResume();
    	
    	if (mFout != null) {
    		mBtSend.setEnabled(true);
    		return;
    	}
    	
    	UsbAccessory[] accessories = mUsbManager.getAccessoryList();
    	UsbAccessory accessory = (accessories == null? null : accessories[0]);
    	
    	if (accessory != null) {
    		if (mUsbManager.hasPermission(accessory)) {
    			openAccessory(accessory);
    			mBtSend.setEnabled(true);
    		}
    		else {
    			synchronized(mUsbReceiver) {
    				if (!mPermissionRequestPending) {
    					mUsbManager.requestPermission(accessory, mPermissionIntent);
    					mPermissionRequestPending = true;
    				}
    			}
    		}
    	}
    	else {
    		Log.d(TAG, "mAccessory is null");
    	}
    	
    }
    
    @Override
    public void onPause() {
    	if (DEBUG) Log.d(TAG, "onPause()");
    	
    	super.onPause();
    	closeAccessory();
    	mBtSend.setEnabled(false);
    }
    
    @Override
    protected void onDestroy() {
    	if (DEBUG) Log.d(TAG, "onDestroy()");
    	unregisterReceiver(mUsbReceiver);
    	super.onDestroy();
    }
    
    private void openAccessory(UsbAccessory accessory) {
    	mFd = mUsbManager.openAccessory(accessory);
    	if (mFd != null) {
    		mAccessory = accessory;
    		FileDescriptor fd = mFd.getFileDescriptor();
    		mFout = new FileOutputStream(fd);
    	}
    	else {
    		Log.d(TAG, "accessory open fail");
    	}
    }
    
    private void closeAccessory() {
    	try {
    		if (mFd != null) {
    			mFout.close();
    			mFd.close();
    		}
    	}
    	catch (IOException e) {
    	}
    	finally {
    		mFd = null;
    		mFout = null;
    		mAccessory = null;
    	}
    }
    
    public void queueWrite(final String data){
    	if(mAccessory == null){
    		return;
    	}
    	new Thread(new Runnable() {
			@Override
			public void run() {
				try {
					Log.d(TAG, "Writing length "+data.length());
					mFout.write(new byte[]{(byte)data.length()});
					Log.d(TAG, "Writing data: "+data);
					mFout.write(data.getBytes());
					Log.d(TAG,"Done writing");
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}).start();
    }
    
	private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
		@Override
		public void onReceive(Context context, Intent intent) {
			String action = intent.getAction();
			if (UsbManager.ACTION_USB_ACCESSORY_DETACHED.equals(action)) {
				UsbAccessory accessory = UsbManager.getAccessory(intent);
				if (accessory != null && accessory.equals(mAccessory)) {
					if (DEBUG) Log.d(TAG,"Dettached!");
					closeAccessory();
					mBtSend.setEnabled(false);
				}
			} else if(ACTION_USB_PERMISSION.equals(action)){
				l("permission answered");
				synchronized(this) {
					UsbAccessory accessory = UsbManager.getAccessory(intent);
					if(intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)){
						openAccessory(accessory);
						mBtSend.setEnabled(true);
					}
					else {
						Log.d(TAG, "permission denied");
					}
					mPermissionRequestPending = false;
				}
			}
			else {
				Log.d(TAG, "Unknown action: " + action);
			}
		}
	};
	
	private void l(String l){
		if (DEBUG) Log.d(TAG, l);
	}
}