CaptureActivityHandler.java

/*
 * 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.barcode.decode;

import java.util.Collection;
import java.util.Vector;

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.barcode.CaptureAty;
import com.barcode.camera.CameraManager;
import com.barcode.view.ViewfinderResultPointCallback;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.Result;
import com.ttj.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 CaptureAty 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(CaptureAty activity,
			Collection<BarcodeFormat> decodeFormats, String characterSet,
			CameraManager cameraManager) {
		this.activity = activity;

		// 启动扫描线程
		decodeThread = new DecodeThread(activity, decodeFormats, 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) {
		if (message.what == R.id.restart_preview) {
			Log.d(TAG, "Got restart preview message");
			restartPreviewAndDecode();
		} else if (message.what == 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);
		} else if (message.what == 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);
		} else if (message.what == R.id.return_scan_result) {
			Log.d(TAG, "Got return scan result message");
			activity.setResult(Activity.RESULT_OK, (Intent) message.obj);
			activity.finish();
		} else if (message.what == 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);
			}
		}
	}

	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();
		}
	}

	public void setDecodeFormats(Vector<BarcodeFormat> paramVector) {
		this.decodeThread.setDecodeFormats(paramVector);
	}
}