android开发摇晃手机扫描二维码

/* * 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.zijunlin.Zxing.Demo.camera; import android.content.Context; import android.content.SharedPreferences; 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.preference.PreferenceManager; import android.util.Log; import android.view.SurfaceHolder; import java.io.IOException; /** * 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. * * @author dswitkin@google.com (Daniel Switkin) */ public final class CameraManager { private static final String TAG = CameraManager.class.getSimpleName(); private static final int MIN_FRAME_WIDTH = 240; private static final int MIN_FRAME_HEIGHT = 240; private static final int MAX_FRAME_WIDTH = 480; private static final int MAX_FRAME_HEIGHT = 360; /** * 定义一个静态的cameraManager */ private static CameraManager cameraManager; /** * 获取构建版本 */ 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; /** * 定义相机配置管理器 */ private final CameraConfigurationManager configManager; /** * 定义相机 */ private Camera camera; private Rect framingRect; private Rect framingRectInPreview; private boolean initialized; private boolean previewing; /** * 定义是否是一次性回调，如果为true的话就是拍一下就停了，再想拍要重新定义拍照的surface */ 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. * 打开相机 * * @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); // SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context); //是否使用前灯 // if (prefs.getBoolean(PreferencesActivity.KEY_FRONT_LIGHT, false)) { // FlashlightManager.enableFlashlight(); // } FlashlightManager.enableFlashlight(); } } /** * Closes the camera driver if still in use. * 关闭相机 */ public void closeDriver() { if (camera != null) { FlashlightManager.disableFlashlight(); camera.release(); camera = null; } } /** * Asks the camera hardware to begin drawing preview frames to the screen. * 相机准备 */ public void startPreview() { if (camera != null && !previewing) { camera.startPreview(); previewing = true; } } /** * Tells the camera to stop drawing preview frames. * 相机暂停 */ 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) { /** * 重新设置handler */ autoFocusCallback.setHandler(handler, message); //Log.d(TAG, "Requesting auto-focus callback"); /** * 让相机自动聚焦 */ 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() { /** * 获得屏幕的大小 */ Point screenResolution = configManager.getScreenResolution(); if (framingRect == null) { if (camera == null) { return null; } /** * 中间矩形宽为屏幕宽的3/4，同时当大于或小于限制值时，设置为限制值 */ int width = screenResolution.x * 4/5; if (width < MIN_FRAME_WIDTH) { wid