Zxing里面的东西，在拍照时设置相机参数 会用到，所以记下来（日记）

/* 第一个 <span style="font-family: Arial, Helvetica, sans-serif;">CameraConfigurationManager </span>是github上大神写的，第二个是Zxing里面的*/

import java.util.regex.Pattern;import android.content.Context;import android.graphics.Point;import android.hardware.Camera;import android.os.Build;import android.util.Log;import android.view.Display;import android.view.WindowManager;/** * 描述: 相机参数配置 */final class CameraConfigurationManager {private static final String TAG = CameraConfigurationManager.class.getSimpleName();private static final int TEN_DESIRED_ZOOM = 27;private static final Pattern COMMA_PATTERN = Pattern.compile(",");private final Context context;private Point screenResolution;private Point cameraResolution;private int previewFormat;private String previewFormatString;CameraConfigurationManager(Context context) {this.context = context;}@SuppressWarnings("deprecation")void initFromCameraParameters(Camera camera) {Camera.Parameters parameters = camera.getParameters();previewFormat = parameters.getPreviewFormat();previewFormatString = parameters.get("preview-format");WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);Display display = manager.getDefaultDisplay();screenResolution = new Point(display.getWidth(), display.getHeight());    Point screenResolutionForCamera = new Point();       screenResolutionForCamera.x = screenResolution.x;       screenResolutionForCamera.y = screenResolution.y;           if (screenResolution.x < screenResolution.y) {           screenResolutionForCamera.x = screenResolution.y;           screenResolutionForCamera.y = screenResolution.x;    }cameraResolution = getCameraResolution(parameters, screenResolutionForCamera);}void setDesiredCameraParameters(Camera camera) {Camera.Parameters parameters = camera.getParameters();parameters.setPreviewSize(cameraResolution.x, cameraResolution.y);setFlash(parameters);setZoom(parameters);camera.setDisplayOrientation(90);camera.setParameters(parameters);}Point getCameraResolution() {return cameraResolution;}Point getScreenResolution() {return screenResolution;}int getPreviewFormat() {return previewFormat;}String getPreviewFormatString() {return previewFormatString;}private static Point getCameraResolution(Camera.Parameters parameters,Point screenResolution) {String previewSizeValueString = parameters.get("preview-size-values");if (previewSizeValueString == null) {previewSizeValueString = parameters.get("preview-size-value");}Point cameraResolution = null;if (previewSizeValueString != null) {cameraResolution = findBestPreviewSizeValue(previewSizeValueString,screenResolution);}if (cameraResolution == null) {cameraResolution = new Point((screenResolution.x >> 3) << 3,(screenResolution.y >> 3) << 3);}return cameraResolution;}private static Point findBestPreviewSizeValue(CharSequence previewSizeValueString, Point screenResolution) {int bestX = 0;int bestY = 0;int diff = Integer.MAX_VALUE;for (String previewSize : COMMA_PATTERN.split(previewSizeValueString)) {previewSize = previewSize.trim();int dimPosition = previewSize.indexOf('x');if (dimPosition < 0) {continue;}int newX;int newY;try {newX = Integer.parseInt(previewSize.substring(0, dimPosition));newY = Integer.parseInt(previewSize.substring(dimPosition + 1));} catch (NumberFormatException nfe) {continue;}int newDiff = Math.abs(newX - screenResolution.x)+ Math.abs(newY - screenResolution.y);if (newDiff == 0) {bestX = newX;bestY = newY;break;} else if (newDiff < diff) {bestX = newX;bestY = newY;diff = newDiff;}}if (bestX > 0 && bestY > 0) {return new Point(bestX, bestY);}return null;}private static int findBestMotZoomValue(CharSequence stringValues,int tenDesiredZoom) {int tenBestValue = 0;for (String stringValue : COMMA_PATTERN.split(stringValues)) {stringValue = stringValue.trim();double value;try {value = Double.parseDouble(stringValue);} catch (NumberFormatException nfe) {return tenDesiredZoom;}int tenValue = (int) (10.0 * value);if (Math.abs(tenDesiredZoom - value) < Math.abs(tenDesiredZoom- tenBestValue)) {tenBestValue = tenValue;}}return tenBestValue;}private void setFlash(Camera.Parameters parameters) {if (Build.MODEL.contains("Behold II") && CameraManager.SDK_INT == 3) { // 3parameters.set("flash-value", 1);} else {parameters.set("flash-value", 2);}parameters.set("flash-mode", "off");}private void setZoom(Camera.Parameters parameters) {String zoomSupportedString = parameters.get("zoom-supported");if (zoomSupportedString != null&& !Boolean.parseBoolean(zoomSupportedString)) {return;}int tenDesiredZoom = TEN_DESIRED_ZOOM;String maxZoomString = parameters.get("max-zoom");if (maxZoomString != null) {try {int tenMaxZoom = (int) (10.0 * Double.parseDouble(maxZoomString));if (tenDesiredZoom > tenMaxZoom) {tenDesiredZoom = tenMaxZoom;}} catch (NumberFormatException nfe) {Log.w(TAG, "Bad max-zoom: " + maxZoomString);}}String takingPictureZoomMaxString = parameters.get("taking-picture-zoom-max");if (takingPictureZoomMaxString != null) {try {int tenMaxZoom = Integer.parseInt(takingPictureZoomMaxString);if (tenDesiredZoom > tenMaxZoom) {tenDesiredZoom = tenMaxZoom;}} catch (NumberFormatException nfe) {Log.w(TAG, "Bad taking-picture-zoom-max: "+ takingPictureZoomMaxString);}}String motZoomValuesString = parameters.get("mot-zoom-values");if (motZoomValuesString != null) {tenDesiredZoom = findBestMotZoomValue(motZoomValuesString,tenDesiredZoom);}String motZoomStepString = parameters.get("mot-zoom-step");if (motZoomStepString != null) {try {double motZoomStep = Double.parseDouble(motZoomStepString.trim());int tenZoomStep = (int) (10.0 * motZoomStep);if (tenZoomStep > 1) {tenDesiredZoom -= tenDesiredZoom % tenZoomStep;}} catch (NumberFormatException nfe) {// continue}}// Set zoom. This helps encourage the user to pull back.// Some devices like the Behold have a zoom parameterif (maxZoomString != null || motZoomValuesString != null) {parameters.set("zoom", String.valueOf(tenDesiredZoom / 10.0));}// Most devices, like the Hero, appear to expose this zoom parameter.// It takes on values like "27" which appears to mean 2.7x zoomif (takingPictureZoomMaxString != null) {parameters.set("taking-picture-zoom", tenDesiredZoom);}}}

<pre name="code" class="java">/* * Copyright (C) 2014 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;import android.annotation.TargetApi;import android.graphics.Point;import android.graphics.Rect;import android.hardware.Camera;import android.os.Build;import android.util.Log;import java.util.ArrayList;import java.util.Arrays;import java.util.Collection;import java.util.Collections;import java.util.Comparator;import java.util.Iterator;import java.util.List;import java.util.regex.Pattern;/** * Utility methods for configuring the Android camera. * * @author Sean Owen */@TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)public final class CameraConfigurationUtils {  private static final String TAG = "CameraConfiguration";  private static final Pattern SEMICOLON = Pattern.compile(";");  private static final int MIN_PREVIEW_PIXELS = 480 * 320; // normal screen  private static final float MAX_EXPOSURE_COMPENSATION = 1.5f;  private static final float MIN_EXPOSURE_COMPENSATION = 0.0f;  private static final double MAX_ASPECT_DISTORTION = 0.15;  private static final int MIN_FPS = 10;  private static final int MAX_FPS = 20;  private static final int AREA_PER_1000 = 400;  private CameraConfigurationUtils() {  }  public static void setFocus(Camera.Parameters parameters,                              boolean autoFocus,                              boolean disableContinuous,                              boolean safeMode) {    List<String> supportedFocusModes = parameters.getSupportedFocusModes();    String focusMode = null;    if (autoFocus) {      if (safeMode || disableContinuous) {        focusMode = findSettableValue("focus mode",                                       supportedFocusModes,                                       Camera.Parameters.FOCUS_MODE_AUTO);      } else {        focusMode = findSettableValue("focus mode",                                      supportedFocusModes,                                      Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE,                                      Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO,                                      Camera.Parameters.FOCUS_MODE_AUTO);      }    }    // Maybe selected auto-focus but not available, so fall through here:    if (!safeMode && focusMode == null) {      focusMode = findSettableValue("focus mode",                                    supportedFocusModes,                                    Camera.Parameters.FOCUS_MODE_MACRO,                                    Camera.Parameters.FOCUS_MODE_EDOF);    }    if (focusMode != null) {      if (focusMode.equals(parameters.getFocusMode())) {        Log.i(TAG, "Focus mode already set to " + focusMode);      } else {        parameters.setFocusMode(focusMode);      }    }  }  public static void setTorch(Camera.Parameters parameters, boolean on) {    List<String> supportedFlashModes = parameters.getSupportedFlashModes();    String flashMode;    if (on) {      flashMode = findSettableValue("flash mode",                                    supportedFlashModes,                                    Camera.Parameters.FLASH_MODE_TORCH,                                    Camera.Parameters.FLASH_MODE_ON);    } else {      flashMode = findSettableValue("flash mode",                                    supportedFlashModes,                                    Camera.Parameters.FLASH_MODE_OFF);    }    if (flashMode != null) {      if (flashMode.equals(parameters.getFlashMode())) {        Log.i(TAG, "Flash mode already set to " + flashMode);      } else {        Log.i(TAG, "Setting flash mode to " + flashMode);        parameters.setFlashMode(flashMode);      }    }  }  public static void setBestExposure(Camera.Parameters parameters, boolean lightOn) {    int minExposure = parameters.getMinExposureCompensation();    int maxExposure = parameters.getMaxExposureCompensation();    float step = parameters.getExposureCompensationStep();    if ((minExposure != 0 || maxExposure != 0) && step > 0.0f) {      // Set low when light is on      float targetCompensation = lightOn ? MIN_EXPOSURE_COMPENSATION : MAX_EXPOSURE_COMPENSATION;      int compensationSteps = Math.round(targetCompensation / step);      float actualCompensation = step * compensationSteps;      // Clamp value:      compensationSteps = Math.max(Math.min(compensationSteps, maxExposure), minExposure);      if (parameters.getExposureCompensation() == compensationSteps) {        Log.i(TAG, "Exposure compensation already set to " + compensationSteps + " / " + actualCompensation);      } else {        Log.i(TAG, "Setting exposure compensation to " + compensationSteps + " / " + actualCompensation);        parameters.setExposureCompensation(compensationSteps);      }    } else {      Log.i(TAG, "Camera does not support exposure compensation");    }  }  public static void setBestPreviewFPS(Camera.Parameters parameters) {    setBestPreviewFPS(parameters, MIN_FPS, MAX_FPS);  }  public static void setBestPreviewFPS(Camera.Parameters parameters, int minFPS, int maxFPS) {    List<int[]> supportedPreviewFpsRanges = parameters.getSupportedPreviewFpsRange();    Log.i(TAG, "Supported FPS ranges: " + toString(supportedPreviewFpsRanges));    if (supportedPreviewFpsRanges != null && !supportedPreviewFpsRanges.isEmpty()) {      int[] suitableFPSRange = null;      for (int[] fpsRange : supportedPreviewFpsRanges) {        int thisMin = fpsRange[Camera.Parameters.PREVIEW_FPS_MIN_INDEX];        int thisMax = fpsRange[Camera.Parameters.PREVIEW_FPS_MAX_INDEX];        if (thisMin >= minFPS * 1000 && thisMax <= maxFPS * 1000) {          suitableFPSRange = fpsRange;          break;        }      }      if (suitableFPSRange == null) {        Log.i(TAG, "No suitable FPS range?");      } else {        int[] currentFpsRange = new int[2];        parameters.getPreviewFpsRange(currentFpsRange);        if (Arrays.equals(currentFpsRange, suitableFPSRange)) {          Log.i(TAG, "FPS range already set to " + Arrays.toString(suitableFPSRange));        } else {          Log.i(TAG, "Setting FPS range to " + Arrays.toString(suitableFPSRange));          parameters.setPreviewFpsRange(suitableFPSRange[Camera.Parameters.PREVIEW_FPS_MIN_INDEX],                                        suitableFPSRange[Camera.Parameters.PREVIEW_FPS_MAX_INDEX]);        }      }    }  }  public static void setFocusArea(Camera.Parameters parameters) {    if (parameters.getMaxNumFocusAreas() > 0) {      Log.i(TAG, "Old focus areas: " + toString(parameters.getFocusAreas()));      List<Camera.Area> middleArea = buildMiddleArea(AREA_PER_1000);      Log.i(TAG, "Setting focus area to : " + toString(middleArea));      parameters.setFocusAreas(middleArea);    } else {      Log.i(TAG, "Device does not support focus areas");    }  }  public static void setMetering(Camera.Parameters parameters) {    if (parameters.getMaxNumMeteringAreas() > 0) {      Log.i(TAG, "Old metering areas: " + parameters.getMeteringAreas());      List<Camera.Area> middleArea = buildMiddleArea(AREA_PER_1000);      Log.i(TAG, "Setting metering area to : " + toString(middleArea));      parameters.setMeteringAreas(middleArea);    } else {      Log.i(TAG, "Device does not support metering areas");    }  }  private static List<Camera.Area> buildMiddleArea(int areaPer1000) {    return Collections.singletonList(        new Camera.Area(new Rect(-areaPer1000, -areaPer1000, areaPer1000, areaPer1000), 1));  }  public static void setVideoStabilization(Camera.Parameters parameters) {    if (parameters.isVideoStabilizationSupported()) {      if (parameters.getVideoStabilization()) {        Log.i(TAG, "Video stabilization already enabled");      } else {        Log.i(TAG, "Enabling video stabilization...");        parameters.setVideoStabilization(true);      }    } else {      Log.i(TAG, "This device does not support video stabilization");    }  }  public static void setBarcodeSceneMode(Camera.Parameters parameters) {    if (Camera.Parameters.SCENE_MODE_BARCODE.equals(parameters.getSceneMode())) {      Log.i(TAG, "Barcode scene mode already set");      return;    }    String sceneMode = findSettableValue("scene mode",                                         parameters.getSupportedSceneModes(),                                         Camera.Parameters.SCENE_MODE_BARCODE);    if (sceneMode != null) {      parameters.setSceneMode(sceneMode);    }  }  public static void setZoom(Camera.Parameters parameters, double targetZoomRatio) {    if (parameters.isZoomSupported()) {      Integer zoom = indexOfClosestZoom(parameters, targetZoomRatio);      if (zoom == null) {        return;      }      if (parameters.getZoom() == zoom) {        Log.i(TAG, "Zoom is already set to " + zoom);      } else {        Log.i(TAG, "Setting zoom to " + zoom);        parameters.setZoom(zoom);      }    } else {      Log.i(TAG, "Zoom is not supported");    }  }  private static Integer indexOfClosestZoom(Camera.Parameters parameters, double targetZoomRatio) {    List<Integer> ratios = parameters.getZoomRatios();    Log.i(TAG, "Zoom ratios: " + ratios);    int maxZoom = parameters.getMaxZoom();    if (ratios == null || ratios.isEmpty() || ratios.size() != maxZoom + 1) {      Log.w(TAG, "Invalid zoom ratios!");      return null;    }    double target100 = 100.0 * targetZoomRatio;    double smallestDiff = Double.POSITIVE_INFINITY;    int closestIndex = 0;    for (int i = 0; i < ratios.size(); i++) {      double diff = Math.abs(ratios.get(i) - target100);      if (diff < smallestDiff) {        smallestDiff = diff;        closestIndex = i;      }    }    Log.i(TAG, "Chose zoom ratio of " + (ratios.get(closestIndex) / 100.0));    return closestIndex;  }  public static void setInvertColor(Camera.Parameters parameters) {    if (Camera.Parameters.EFFECT_NEGATIVE.equals(parameters.getColorEffect())) {      Log.i(TAG, "Negative effect already set");      return;    }    String colorMode = findSettableValue("color effect",                                         parameters.getSupportedColorEffects(),                                         Camera.Parameters.EFFECT_NEGATIVE);    if (colorMode != null) {      parameters.setColorEffect(colorMode);    }  }  public static Point findBestPreviewSizeValue(Camera.Parameters parameters, Point screenResolution) {    List<Camera.Size> rawSupportedSizes = parameters.getSupportedPreviewSizes();    if (rawSupportedSizes == null) {      Log.w(TAG, "Device returned no supported preview sizes; using default");      Camera.Size defaultSize = parameters.getPreviewSize();      if (defaultSize == null) {        throw new IllegalStateException("Parameters contained no preview size!");      }      return new Point(defaultSize.width, defaultSize.height);    }    // Sort by size, descending    List<Camera.Size> supportedPreviewSizes = new ArrayList<>(rawSupportedSizes);    Collections.sort(supportedPreviewSizes, new Comparator<Camera.Size>() {      @Override      public int compare(Camera.Size a, Camera.Size b) {        int aPixels = a.height * a.width;        int bPixels = b.height * b.width;        if (bPixels < aPixels) {          return -1;        }        if (bPixels > aPixels) {          return 1;        }        return 0;      }    });    if (Log.isLoggable(TAG, Log.INFO)) {      StringBuilder previewSizesString = new StringBuilder();      for (Camera.Size supportedPreviewSize : supportedPreviewSizes) {        previewSizesString.append(supportedPreviewSize.width).append('x')            .append(supportedPreviewSize.height).append(' ');      }      Log.i(TAG, "Supported preview sizes: " + previewSizesString);    }    double screenAspectRatio = (double) screenResolution.x / (double) screenResolution.y;    // Remove sizes that are unsuitable    Iterator<Camera.Size> it = supportedPreviewSizes.iterator();    while (it.hasNext()) {      Camera.Size supportedPreviewSize = it.next();      int realWidth = supportedPreviewSize.width;      int realHeight = supportedPreviewSize.height;      if (realWidth * realHeight < MIN_PREVIEW_PIXELS) {        it.remove();        continue;      }      boolean isCandidatePortrait = realWidth < realHeight;      int maybeFlippedWidth = isCandidatePortrait ? realHeight : realWidth;      int maybeFlippedHeight = isCandidatePortrait ? realWidth : realHeight;      double aspectRatio = (double) maybeFlippedWidth / (double) maybeFlippedHeight;      double distortion = Math.abs(aspectRatio - screenAspectRatio);      if (distortion > MAX_ASPECT_DISTORTION) {        it.remove();        continue;      }      if (maybeFlippedWidth == screenResolution.x && maybeFlippedHeight == screenResolution.y) {        Point exactPoint = new Point(realWidth, realHeight);        Log.i(TAG, "Found preview size exactly matching screen size: " + exactPoint);        return exactPoint;      }    }    // If no exact match, use largest preview size. This was not a great idea on older devices because    // of the additional computation needed. We're likely to get here on newer Android 4+ devices, where    // the CPU is much more powerful.    if (!supportedPreviewSizes.isEmpty()) {      Camera.Size largestPreview = supportedPreviewSizes.get(0);      Point largestSize = new Point(largestPreview.width, largestPreview.height);      Log.i(TAG, "Using largest suitable preview size: " + largestSize);      return largestSize;    }    // If there is nothing at all suitable, return current preview size    Camera.Size defaultPreview = parameters.getPreviewSize();    if (defaultPreview == null) {      throw new IllegalStateException("Parameters contained no preview size!");    }    Point defaultSize = new Point(defaultPreview.width, defaultPreview.height);    Log.i(TAG, "No suitable preview sizes, using default: " + defaultSize);    return defaultSize;  }  private static String findSettableValue(String name,                                          Collection<String> supportedValues,                                          String... desiredValues) {    Log.i(TAG, "Requesting " + name + " value from among: " + Arrays.toString(desiredValues));    Log.i(TAG, "Supported " + name + " values: " + supportedValues);    if (supportedValues != null) {      for (String desiredValue : desiredValues) {        if (supportedValues.contains(desiredValue)) {          Log.i(TAG, "Can set " + name + " to: " + desiredValue);          return desiredValue;        }      }    }    Log.i(TAG, "No supported values match");    return null;  }  private static String toString(Collection<int[]> arrays) {    if (arrays == null || arrays.isEmpty()) {      return "[]";    }    StringBuilder buffer = new StringBuilder();    buffer.append('[');    Iterator<int[]> it = arrays.iterator();    while (it.hasNext()) {      buffer.append(Arrays.toString(it.next()));      if (it.hasNext()) {        buffer.append(", ");      }    }    buffer.append(']');    return buffer.toString();  }  private static String toString(Iterable<Camera.Area> areas) {    if (areas == null) {      return null;    }    StringBuilder result = new StringBuilder();    for (Camera.Area area : areas) {      result.append(area.rect).append(':').append(area.weight).append(' ');    }    return result.toString();  }  public static String collectStats(Camera.Parameters parameters) {    return collectStats(parameters.flatten());  }  public static String collectStats(CharSequence flattenedParams) {    StringBuilder result = new StringBuilder(1000);    result.append("BOARD=").append(Build.BOARD).append('\n');    result.append("BRAND=").append(Build.BRAND).append('\n');    result.append("CPU_ABI=").append(Build.CPU_ABI).append('\n');    result.append("DEVICE=").append(Build.DEVICE).append('\n');    result.append("DISPLAY=").append(Build.DISPLAY).append('\n');    result.append("FINGERPRINT=").append(Build.FINGERPRINT).append('\n');    result.append("HOST=").append(Build.HOST).append('\n');    result.append("ID=").append(Build.ID).append('\n');    result.append("MANUFACTURER=").append(Build.MANUFACTURER).append('\n');    result.append("MODEL=").append(Build.MODEL).append('\n');    result.append("PRODUCT=").append(Build.PRODUCT).append('\n');    result.append("TAGS=").append(Build.TAGS).append('\n');    result.append("TIME=").append(Build.TIME).append('\n');    result.append("TYPE=").append(Build.TYPE).append('\n');    result.append("USER=").append(Build.USER).append('\n');    result.append("VERSION.CODENAME=").append(Build.VERSION.CODENAME).append('\n');    result.append("VERSION.INCREMENTAL=").append(Build.VERSION.INCREMENTAL).append('\n');    result.append("VERSION.RELEASE=").append(Build.VERSION.RELEASE).append('\n');    result.append("VERSION.SDK_INT=").append(Build.VERSION.SDK_INT).append('\n');    if (flattenedParams != null) {      String[] params = SEMICOLON.split(flattenedParams);      Arrays.sort(params);      for (String param : params) {        result.append(param).append('\n');      }    }    return result.toString();  }}