usb-serial-for-android/UsbSerialExamples/src/com/hoho/android/usbserial/examples/DemoActivity.java

/* Copyright 2011 Google Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * Project home page: http://code.google.com/p/usb-serial-for-android/
 */

package com.hoho.android.usbserial.examples;

import android.app.Activity;
import android.content.Context;
import android.hardware.usb.UsbManager;
import android.os.Bundle;
import android.util.Log;
import android.widget.ScrollView;
import android.widget.TextView;

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

import java.io.IOException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * A sample Activity demonstrating USB-Serial support.
 *
 * @author mike wakerly (opensource@hoho.com)
 */
public class DemoActivity extends Activity {

    private final String TAG = DemoActivity.class.getSimpleName();

    /**
     * The device currently in use, or {@code null}.
     */
    private UsbSerialDriver mSerialDevice;

    /**
     * The system's USB service.
     */
    private UsbManager mUsbManager;

    private TextView mTitleTextView;
    private TextView mDumpTextView;
    private ScrollView mScrollView;

    private final ExecutorService mExecutor = Executors.newSingleThreadExecutor();

    private SerialInputOutputManager mSerialIoManager;

    private final SerialInputOutputManager.Listener mListener =
            new SerialInputOutputManager.Listener() {

        @Override
        public void onRunError(Exception e) {
            Log.d(TAG, "Runner stopped.");
        }

        @Override
        public void onNewData(final byte[] data) {
            DemoActivity.this.runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    DemoActivity.this.updateReceivedData(data);
                }
            });
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
        mTitleTextView = (TextView) findViewById(R.id.demoTitle);
        mDumpTextView = (TextView) findViewById(R.id.demoText);
        mScrollView = (ScrollView) findViewById(R.id.demoScroller);
    }

    @Override
    protected void onPause() {
        super.onPause();
        stopIoManager();
        if (mSerialDevice != null) {
            try {
                mSerialDevice.close();
            } catch (IOException e) {
                // Ignore.
            }
            mSerialDevice = null;
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        mSerialDevice = UsbSerialProber.acquire(mUsbManager);
        Log.d(TAG, "Resumed, mSerialDevice=" + mSerialDevice);
        if (mSerialDevice == null) {
            mTitleTextView.setText("No serial device.");
        } else {
            try {
                mSerialDevice.open();
            } catch (IOException e) {
                Log.e(TAG, "Error setting up device: " + e.getMessage(), e);
                mTitleTextView.setText("Error opening device: " + e.getMessage());
                try {
                    mSerialDevice.close();
                } catch (IOException e2) {
                    // Ignore.
                }
                mSerialDevice = null;
                return;
            }
            mTitleTextView.setText("Serial device: " + mSerialDevice);
        }
        onDeviceStateChange();
    }

    private void stopIoManager() {
        if (mSerialIoManager != null) {
            Log.i(TAG, "Stopping io manager ..");
            mSerialIoManager.stop();
            mSerialIoManager = null;
        }
    }

    private void startIoManager() {
        if (mSerialDevice != null) {
            Log.i(TAG, "Starting io manager ..");
            mSerialIoManager = new SerialInputOutputManager(mSerialDevice, mListener);
            mExecutor.submit(mSerialIoManager);
        }
    }

    private void onDeviceStateChange() {
        stopIoManager();
        startIoManager();
    }

    private void updateReceivedData(byte[] data) {
        final String message = "Read " + data.length + " bytes: \n"
                + HexDump.dumpHexString(data) + "\n\n";
        mDumpTextView.append(message);
        mScrollView.smoothScrollTo(0, mDumpTextView.getBottom());
    }

}