Android Open Source - qrcode-android Decode Thread

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License

The source code is released under:

MIT License

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Java Source Code

/*
 * Copyright (C) 2008 ZXing authors//from   www  . j  a  va  2s  .  c o  m
 *
 * 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 com.google.zxing.client.android;

import android.content.SharedPreferences;
import android.os.Handler;
import android.os.Looper;
import android.preference.PreferenceManager;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.DecodeHintType;
import com.google.zxing.ResultPointCallback;

import java.util.Collection;
import java.util.EnumMap;
import java.util.EnumSet;
import java.util.Map;
import java.util.concurrent.CountDownLatch;

/**
 * This thread does all the heavy lifting of decoding the images.
 *
 * @author dswitkin@google.com (Daniel Switkin)
 */
final class DecodeThread extends Thread
{

    public static final String BARCODE_BITMAP = "barcode_bitmap";

    private final CaptureActivity activity;
    private final Map<DecodeHintType, Object> hints;
    private Handler handler;
    private final CountDownLatch handlerInitLatch;

    DecodeThread(CaptureActivity activity,
                 Collection<BarcodeFormat> decodeFormats,
                 String characterSet,
                 ResultPointCallback resultPointCallback)
    {

        this.activity = activity;
        handlerInitLatch = new CountDownLatch(1);

        hints = new EnumMap<DecodeHintType, Object>(DecodeHintType.class);

        // The prefs can't change while the thread is running, so pick them up once here.
        //todo: handle support of decode formats via intent
        if (decodeFormats == null || decodeFormats.isEmpty())
        {
            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(activity);
            decodeFormats = EnumSet.noneOf(BarcodeFormat.class);
            decodeFormats.addAll(DecodeFormatManager.QR_CODE_FORMATS);
            decodeFormats.addAll(DecodeFormatManager.ONE_D_FORMATS);

            hints.put(DecodeHintType.POSSIBLE_FORMATS, decodeFormats);

            if (characterSet != null)
            {
                hints.put(DecodeHintType.CHARACTER_SET, characterSet);
            }
            hints.put(DecodeHintType.NEED_RESULT_POINT_CALLBACK, resultPointCallback);
        }
    }

    Handler getHandler()
    {
        try
        {
            handlerInitLatch.await();
        } catch (InterruptedException ie)
        {
            // continue?
        }
        return handler;
    }

    @Override
    public void run()
    {
        Looper.prepare();
        handler = new DecodeHandler(activity, hints);
        handlerInitLatch.countDown();
        Looper.loop();
    }

}

Java Source Code List