Android 基于google Zxing实现二维码的生成，识别和长按识别的效果

/* * 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.zxing.camera; import java.io.IOException; import android.content.Context; import android.graphics.PixelFormat; import android.graphics.Point; import android.graphics.Rect; import android.hardware.Camera; import android.os.Build; import android.os.Handler; import android.util.DisplayMetrics; import android.util.Log; import android.view.SurfaceHolder; /** * This object wraps the Camera service object and expects to be the only one talking to it. The * implementation encapsulates the steps needed to take preview-sized images, which are used for * both preview and decoding. * */ public final class CameraManager { private static final String TAG = CameraManager.class.getSimpleName(); private static final int MIN_FRAME_WIDTH = 580; private static final int MIN_FRAME_HEIGHT = 580; private static final int MAX_FRAME_WIDTH = 580; private static final int MAX_FRAME_HEIGHT = 580; private static CameraManager cameraManager; static final int SDK_INT; // Later we can use Build.VERSION.SDK_INT static { int sdkInt; try { sdkInt = Integer.parseInt(Build.VERSION.SDK); } catch (NumberFormatException nfe) { // Just to be safe sdkInt = 10000; } SDK_INT = sdkInt; } private final Context context; private final CameraConfigurationManager configManager; private Camera camera; private Rect framingRect; private Rect framingRectInPreview; private boolean initialized; private boolean previewing; private final boolean useOneShotPreviewCallback; /** * Preview frames are delivered here, which we pass on to the registered handler. Make sure to * clear the handler so it will only receive one message. */ private final PreviewCallback previewCallback; /** Autofocus callbacks arrive here, and are dispatched to the Handler which requested them. */ private final AutoFocusCallback autoFocusCallback; /** * Initializes this static object with the Context of the calling Activity. * * @param context The Activity which wants to use the camera. */ public static void init(Context context) { if (cameraManager == null) { cameraManager = new CameraManager(context); } } /** * Gets the CameraManager singleton instance. * * @return A reference to the CameraManager singleton. */ public static CameraManager get() { return cameraManager; } private CameraManager(Context context) { this.context = context; this.configManager = new CameraConfigurationManager(context); // Camera.setOneShotPreviewCallback() has a race condition in Cupcake, so we use the older // Camera.setPreviewCallback() on 1.5 and earlier. For Donut and later, we need to use // the more efficient one shot callback, as the older one can swamp the system and cause it // to run out of memory. We can't use SDK_INT because it was introduced in the Donut SDK. //useOneShotPreviewCallback = Integer.parseInt(Build.VERSION.SDK) > Build.VERSION_CODES.CUPCAKE; useOneShotPreviewCallback = Integer.parseInt(Build.VERSION.SDK) > 3; // 3 = Cupcake previewCallback = new PreviewCallback(configManager, useOneShotPreviewCallback); autoFocusCallback = new AutoFocusCallback(); } /** * Opens the camera driver and initializes the hardware parameters. * * @param holder The surface object which the camera will draw preview frames into. * @throws IOException Indicates the camera driver failed to open. */ public void openDriver(SurfaceHolder holder) throws IOException { if (camera == null) { camera = Camera.open(); if (camera == null) { throw new IOException(); } camera.setPreviewDisplay(holder); if (!initialized) { initialized = true; configManager.initFromCameraParameters(camera); } configManager.setDesiredCameraParameters(camera); //FIXME // SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context); //�Ƿ�ʹ��ǰ�� // if (prefs.getBoolean(PreferencesActivity.KEY_FRONT_LIGHT, false)) { // FlashlightManager.enableFlashlight(); // } FlashlightManager.enableFlashlight(); } } /** * Closes the camera driver if still in use. */ public void closeDriver() { if (camera != null) { FlashlightManager.disableFlashlight(); camera.release(); camera = null; } } /** * Asks the camera hardware to begin drawing preview frames to the screen. */ public void startPreview() { if (camera != null && !previewing) { camera.startPreview(); previewing = true; } } /** * Tells the camera to stop drawing preview frames. */ public void stopPreview() { if (camera != null && previewing) { if (!useOneShotPreviewCallback) { camera.setPreviewCallback(null); } camera.stopPreview(); previewCallback.setHandler(null, 0); autoFocusCallback.setHandler(null, 0); previewing = false; } } /** * A single preview frame will be returned to the handler supplied. The data will arrive as byte[] * in the message.obj field, with width and height encoded as message.arg1 and message.arg2, * respectively. * * @param handler The handler to send the message to. * @param message The what field of the message to be sent. */ public void requestPreviewFrame(Handler handler, int message) { if (camera != null && previewing) { previewCallback.setHandler(handler, message); if (useOneShotPreviewCallback) { camera.setOneShotPreviewCallback(previewCallback); } else { camera.setPreviewCallback(previewCallback); } } } /** * Asks the camera hardware to perform an autofocus. * * @param handler The Handler to notify when the autofocus completes. * @param message The message to deliver. */ public void requestAutoFocus(Handler handler, int message) { if (camera != null && previewing) { autoFocusCallback.setHandler(handler, message); //Log.d(TAG, "Requesting auto-focus callback"); camera.autoFocus(autoFocusCallback); } } /** * Calculates the framing rect which the UI should draw to show the user where to place the * barcode. This target helps with alignment as well as forces the user to hold the device * far enough away to ensure the image will be in focus. * * @return The rectangle to draw on screen in window coordinates. */ public Rect getFramingRect() { Point screenResolution = configManager.getScreenResolution(); if (framingRect == null) { if (camera == null) { return null; } int width = screenResolution.x * 3 / 4; if (width < MIN_FRAME_WIDTH) { width = MIN_FRAME_WIDTH; } else if (width > MAX_FRAME_WIDTH) { width = MAX_FRAME_WIDTH; } int height = screenResolution.y * 3 / 4; if (height < MIN_FRAME_HEIGHT) { height = MIN_FRAME_HEIGHT; } else if (height > MAX_FRAME_HEIGHT) { height = MAX_FRAME_HEIGHT; } int leftOffset = (screenResolution.x - width) / 2; int topOffset = (screenResolution.y - height) / 2; framingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + height); Log.d(TAG, "Calculated framing rect: " + framingRect); } ret