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      1 /*
      2  * Copyright (C) 2008 ZXing authors
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.zxing.client.android;
     18 
     19 import com.google.zxing.BarcodeFormat;
     20 import com.google.zxing.DecodeHintType;
     21 import com.google.zxing.ResultPointCallback;
     22 
     23 import android.os.Handler;
     24 import android.os.Looper;
     25 
     26 import java.util.Hashtable;
     27 import java.util.Vector;
     28 import java.util.concurrent.CountDownLatch;
     29 
     30 /**
     31  * This thread does all the heavy lifting of decoding the images.
     32  *
     33  * @author dswitkin (at) google.com (Daniel Switkin)
     34  */
     35 final class DecodeThread extends Thread {
     36 
     37   public static final String BARCODE_BITMAP = "barcode_bitmap";
     38 
     39   private final CaptureActivity activity;
     40   private final Hashtable<DecodeHintType,Object> hints;
     41   private Handler handler;
     42   private final CountDownLatch handlerInitLatch;
     43 
     44   DecodeThread(CaptureActivity activity,
     45                String characterSet,
     46                ResultPointCallback resultPointCallback) {
     47 
     48     this.activity = activity;
     49     handlerInitLatch = new CountDownLatch(1);
     50 
     51     hints = new Hashtable<DecodeHintType,Object>();
     52     Vector<BarcodeFormat> formats = new Vector<BarcodeFormat>();
     53     formats.add(BarcodeFormat.QR_CODE);
     54     hints.put(DecodeHintType.POSSIBLE_FORMATS, formats);
     55 
     56     if (characterSet != null) {
     57       hints.put(DecodeHintType.CHARACTER_SET, characterSet);
     58     }
     59     hints.put(DecodeHintType.NEED_RESULT_POINT_CALLBACK, resultPointCallback);
     60   }
     61 
     62   Handler getHandler() {
     63     try {
     64       handlerInitLatch.await();
     65     } catch (InterruptedException ie) {
     66       // continue?
     67     }
     68     return handler;
     69   }
     70 
     71   @Override
     72   public void run() {
     73     Looper.prepare();
     74     handler = new DecodeHandler(activity, hints);
     75     handlerInitLatch.countDown();
     76     Looper.loop();
     77   }
     78 
     79 }
     80