CaptureActivityHandler.java

/**
 * Copyright (C) 2013 Eesti Vabariigi Valimiskomisjon 
 * (Estonian National Electoral Committee), www.vvk.ee
 *
 * Written in 2013 by AS Finestmedia, www.finestmedia.ee
 *
 * Vote-verification application for Estonian Internet voting system
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * This file incorporates work covered by the following copyright and  
 * permission notice:  
 * 
 * Copyright (C) 2008 ZXing authors
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/

package ee.vvk.ivotingverification.qr;

import java.util.Collection;

import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.Result;

import ee.vvk.ivotingverification.QRScannerActivity;
import ee.vvk.ivotingverification.R;
import ee.vvk.ivotingverification.util.Util;

/**
 * This class handles all the messaging which comprises the state machine for
 * capture.
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 */
public final class CaptureActivityHandler extends Handler {

	private static final String TAG = CaptureActivityHandler.class
			.getSimpleName();

	private final QRScannerActivity activity;
	private final DecodeThread decodeThread;
	private State state;
	private final CameraManager cameraManager;

	private enum State {
		PREVIEW, SUCCESS, DONE
	}

	public CaptureActivityHandler(QRScannerActivity activity,
			Collection<BarcodeFormat> decodeFormats, String characterSet,
			CameraManager cameraManager) {
		this.activity = activity;
		decodeThread = new DecodeThread(activity, decodeFormats, characterSet,
				new ViewfinderResultPointCallback(activity.getViewfinderView()));
		decodeThread.start();
		state = State.SUCCESS;

		this.cameraManager = cameraManager;
		cameraManager.startPreview();
		restartPreviewAndDecode();
	}

	@Override
	public void handleMessage(Message message) {

		if (message.what == R.id.auto_focus) {
			if (state == State.PREVIEW) {
				cameraManager.requestAutoFocus(this, R.id.auto_focus);
			}
		} else if (message.what == R.id.restart_preview) {
			if (Util.DEBUGGABLE) {
				Log.d(TAG, "Got restart preview message");
			}
			restartPreviewAndDecode();
		} else if (message.what == R.id.decode_succeeded) {
			if (Util.DEBUGGABLE) {
				Log.d(TAG, "Got decode succeeded message");
			}
			state = State.SUCCESS;
			Bundle bundle = message.getData();
			Bitmap barcode = bundle == null ? null : (Bitmap) bundle
					.getParcelable(DecodeThread.BARCODE_BITMAP);
			activity.handleDecode((Result) message.obj, barcode);
		} else if (message.what == R.id.decode_failed) {
			state = State.PREVIEW;
			cameraManager.requestPreviewFrame(decodeThread.getHandler(),
					R.id.decode);
		} else if (message.what == R.id.return_scan_result) {
			if (Util.DEBUGGABLE) {
				Log.d(TAG, "Got return scan result message");
			}
		}
	}

	public void quitSynchronously() {
		state = State.DONE;
		cameraManager.stopPreview();
		Message quit = Message.obtain(decodeThread.getHandler(), R.id.quit);
		quit.sendToTarget();
		try {
			decodeThread.join(500L);
		} catch (InterruptedException e) {
		}

		removeMessages(R.id.decode_succeeded);
		removeMessages(R.id.decode_failed);
	}

	private void restartPreviewAndDecode() {
		if (state == State.SUCCESS) {
			state = State.PREVIEW;
			cameraManager.requestPreviewFrame(decodeThread.getHandler(),
					R.id.decode);
			cameraManager.requestAutoFocus(this, R.id.auto_focus);
			activity.drawViewfinder();
		}
	}
}