content: /*
   * 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 com.google.zxing.decode;
  
  import android.app.Activity;
  import android.content.ActivityNotFoundException;
  import android.content.Intent;
  import android.content.pm.PackageManager;
  import android.content.pm.ResolveInfo;
  import android.graphics.Bitmap;
  import android.graphics.BitmapFactory;
  import android.net.Uri;
  import android.os.Bundle;
  import android.os.Handler;
  import android.os.Message;
  import android.provider.Browser;
  import android.util.Log;
  
  import com.google.zxing.BarcodeFormat;
  import com.google.zxing.DecodeHintType;
  import com.google.zxing.Result;
  import com.google.zxing.camera.CameraManager;
  import com.google.zxing.view.ViewfinderResultPointCallback;
  import com.jinlin.zxing.CaptureActivity;
  
  import java.util.Collection;
  import java.util.Map;
  
  import cn.jinlin.zxing.R;
  
  
  /**
   * 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 CaptureActivity activity;
  
  	/**
  	 * 真正负责扫描任务的核心线程
  	 */
  	private final DecodeThread decodeThread;
  
  	private State state;
  
  	private final CameraManager cameraManager;
  
  	/**
  	 * 当前扫描的状态
  	 */
  	private enum State {
  		/**
  		 * 预览
  		 */
  		PREVIEW,
  		/**
  		 * 扫描成功
  		 */
  		SUCCESS,
  		/**
  		 * 结束扫描
  		 */
  		DONE
  	}
  
  	public CaptureActivityHandler(CaptureActivity activity,
  			Collection<BarcodeFormat> decodeFormats,
  			Map<DecodeHintType, ?> baseHints, String characterSet,
  			CameraManager cameraManager) {
  		this.activity = activity;
  
  		// 启动扫描线程
  		decodeThread = new DecodeThread(activity, decodeFormats, baseHints,
  				characterSet, new ViewfinderResultPointCallback(
  						activity.getViewfinderView()));
  		decodeThread.start();
  
  		state = State.SUCCESS;
  
  		// Start ourselves capturing previews and decoding.
  		this.cameraManager = cameraManager;
  
  		// 开启相机预览界面
  		cameraManager.startPreview();
  
  		restartPreviewAndDecode();
  	}
  
  	@Override
  	public void handleMessage(Message message) {
  		switch (message.what) {
  			case R.id.restart_preview: // 准备进行下一次扫描
  				Log.d(TAG, "Got restart preview message");
  				restartPreviewAndDecode();
  				break;
  			case R.id.decode_succeeded:
  				Log.d(TAG, "Got decode succeeded message");
  				state = State.SUCCESS;
  				Bundle bundle = message.getData();
  				Bitmap barcode = null;
  				float scaleFactor = 1.0f;
  				if (bundle != null) {
  					byte[] compressedBitmap = bundle
  							.getByteArray(DecodeThread.BARCODE_BITMAP);
  					if (compressedBitmap != null) {
  						barcode = BitmapFactory.decodeByteArray(
  								compressedBitmap, 0, compressedBitmap.length,
  								null);
  						// Mutable copy:
  						barcode = barcode.copy(Bitmap.Config.ARGB_8888, true);
  					}
  					scaleFactor = bundle
  							.getFloat(DecodeThread.BARCODE_SCALED_FACTOR);
  				}
  				activity.handleDecode((Result) message.obj, barcode,
  						scaleFactor);
  				break;
  			case R.id.decode_failed:
  				// We're decoding as fast as possible, so when one decode fails,
  				// start another.
  				state = State.PREVIEW;
  				cameraManager.requestPreviewFrame(decodeThread.getHandler(),
  						R.id.decode);
  				break;
  			case R.id.return_scan_result:
  				Log.d(TAG, "Got return scan result message");
  				activity.setResult(Activity.RESULT_OK, (Intent) message.obj);
  				activity.finish();
  				break;
  			case R.id.launch_product_query:
  				Log.d(TAG, "Got product query message");
  				String url = (String) message.obj;
  
  				Intent intent = new Intent(Intent.ACTION_VIEW);
  				intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
  				intent.setData(Uri.parse(url));
  
  				/**
  				 * 这段代码是zxing项目组想要用chrome打开浏览器浏览url
  				 */
  				ResolveInfo resolveInfo = activity.getPackageManager()
  						.resolveActivity(intent,
  								PackageManager.MATCH_DEFAULT_ONLY);
  				String browserPackageName = null;
  				if (resolveInfo != null && resolveInfo.activityInfo != null) {
  					browserPackageName = resolveInfo.activityInfo.packageName;
  					Log.d(TAG, "Using browser in package " + browserPackageName);
  				}
  
  				// Needed for default Android browser / Chrome only apparently
  				if ("com.android.browser".equals(browserPackageName)
  						|| "com.android.chrome".equals(browserPackageName)) {
  					intent.setPackage(browserPackageName);
  					intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
  					intent.putExtra(Browser.EXTRA_APPLICATION_ID,
  							browserPackageName);
  				}
  
  				try {
  					activity.startActivity(intent);
  				}
  				catch (ActivityNotFoundException ignored) {
  					Log.w(TAG, "Can't find anything to handle VIEW of URI "
  							+ url);
  				}
  				break;
  		}
  	}
  
  	public void quitSynchronously() {
  		state = State.DONE;
  		cameraManager.stopPreview();
  		Message quit = Message.obtain(decodeThread.getHandler(), R.id.quit);
  		quit.sendToTarget();
  
  		try {
  			// Wait at most half a second; should be enough time, and onPause()
  			// will timeout quickly
  			decodeThread.join(500L);
  		}
  		catch (InterruptedException e) {
  			// continue
  		}
  
  		// Be absolutely sure we don't send any queued up messages
  		removeMessages(R.id.decode_succeeded);
  		removeMessages(R.id.decode_failed);
  	}
  
  	/**
  	 * 完成一次扫描后，只需要再调用此方法即可
  	 */
  	private void restartPreviewAndDecode() {
  		if (state == State.SUCCESS) {
  			state = State.PREVIEW;
  
  			// 向decodeThread绑定的handler（DecodeHandler)发送解码消息
  			cameraManager.requestPreviewFrame(decodeThread.getHandler(),
  					R.id.decode);
  			activity.drawViewfinder();
  		}
  	}
  
  }
  