【Android 学习】之二维码扫描开发（闪光灯功能）

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Android二维码扫描我们可以调用Ｚｉｎｇ．ｊａｒ包，用人家写好的代码，我们只需要根据自己的需要修改布局即可．下面我简单介绍一下Ａｎｄｒｏｉｄ我们怎么来用和修改人家的代码．

1、下载Zing.jar包http://download.csdn.net/detail/u013132758/9361939

２、解压导入项目可以用了。

效图如下：

详细介绍一下如何根据自己的需求来修改代码：

首先在ＡｎｄｒｏｉｄＭａｉｎｆｅｓｔ。ｘｍｌ中添加权限

  

 

   
   
    
   
   

１、项目结构如下所示

２、若修改扫描框的大小可在CameraManager里面修改参数width,height该项目中我设置为０．７倍的屏幕宽度。

CameraManager.java

package com.zm.app.zxing.camera;/*
 * 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.
 */

import java.io.IOException;
import java.util.List;

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;

import com.zm.app.zxing.camera.PlanarYUVLuminanceSource;


/**
 * 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 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();
    }
  }
  public void openLight(){
    if (camera != null) {
      Camera.Parameters parameter;
      parameter = camera.getParameters();
      parameter.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
      camera.setParameters(parameter);
    }
  }
  public void offLight(){
    if (camera != null) {
      Camera.Parameters parameter;
      parameter = camera.getParameters();
      parameter.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
      camera.setParameters(parameter);
    }
  }
  /**
   * 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;
      }
      DisplayMetrics metrics = context.getResources().getDisplayMetrics();
      //定义扫描矿的宽和高分别为０．７倍的屏幕宽度和高度
      int width = (int)(metrics.widthPixels*0.7);
      int height = width;

      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);
    }
    return framingRect;
  }

  /**
   * Like {@link #getFramingRect} but coordinates are in terms of the preview frame,
   * not UI / screen.
   */
  public Rect getFramingRectInPreview() {
    if (framingRectInPreview == null) {
      Rect rect = new Rect(getFramingRect());
      Point cameraResolution = configManager.getCameraResolution();
      Point screenResolution = configManager.getScreenResolution();
      //modify here
//      rect.left = rect.left * cameraResolution.x / screenResolution.x;
//      rect.right = rect.right * cameraResolution.x / screenResolution.x;
//      rect.top = rect.top * cameraResolution.y / screenResolution.y;
//      rect.bottom = rect.bottom * cameraResolution.y / screenResolution.y;
      rect.left = rect.left * cameraResolution.y / screenResolution.x;
      rect.right = rect.right * cameraResolution.y / screenResolution.x;
      rect.top = rect.top * cameraResolution.x / screenResolution.y;
      rect.bottom = rect.bottom * cameraResolution.x / screenResolution.y;
      framingRectInPreview = rect;
    }
    return framingRectInPreview;
  }
  /**
   * 通过设置Camera打开闪光灯
   */
  public void turnLightOn()
  {
    Log.e(TAG,"闪光灯相机=======没开");
    if (camera == null)
    {
      Log.e(TAG,"闪光灯相机没开");
      return;
    }
    Log.e(TAG,"闪光灯相机====%%%%%%%===没开");
    Camera.Parameters parameters = camera.getParameters();
    if (parameters == null)
    {
      return;
    }

    List flashModes = parameters.getSupportedFlashModes();
    if (flashModes == null)
    {
      return;
    }
    String flashMode = parameters.getFlashMode();
//    Log.i(TAG, Flash mode:  + flashMode);
//    Log.i(TAG, Flash modes:  + flashModes);
//    // 闪光灯关闭状态
    if (!Camera.Parameters.FLASH_MODE_TORCH.equals(flashMode))
    {
      // Turn on the flash
      if (flashModes.contains(Camera.Parameters.FLASH_MODE_TORCH))
      {
        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
        camera.setParameters(parameters);
        camera.startPreview();
      }
      else
      {
      }
    }
  }

  /**
   * 通过设置Camera关闭闪光灯
   *
   */
  public void turnLightOff()
  {
    if (camera == null)
    {
      Log.e(TAG,"闪光灯相机没开");
      return;

    }
    Camera.Parameters parameters = camera.getParameters();
    if (parameters == null)
    {
      return;
    }
    List flashModes = parameters.getSupportedFlashModes();
    String flashMode = parameters.getFlashMode();
    // Check if camera flash exists
    if (flashModes == null)
    {
      return;
    }
    // 闪光灯打开状态
    if (!Camera.Parameters.FLASH_MODE_OFF.equals(flashMode))
    {
      // Turn off the flash
      if (flashModes.contains(Camera.Parameters.FLASH_MODE_OFF))
      {
        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
        camera.setParameters(parameters);
      }
      else
      {
        Log.e(TAG, "FLASH_MODE_OFF not supported");
      }
    }
  }
  /**
   * Converts the result points from still resolution coordinates to screen coordinates.
   *
   * @param points The points returned by the Reader subclass through Result.getResultPoints().
   * @return An array of Points scaled to the size of the framing rect and offset appropriately
   *         so they can be drawn in screen coordinates.
   */
  /*
  public Point[] convertResultPoints(ResultPoint[] points) {
    Rect frame = getFramingRectInPreview();
    int count = points.length;
    Point[] output = new Point[count];
    for (int x = 0; x < count; x++) {
      output[x] = new Point();
      output[x].x = frame.left + (int) (points[x].getX() + 0.5f);
      output[x].y = frame.top + (int) (points[x].getY() + 0.5f);
    }
    return output;
  }
   */

  /**
   * A factory method to build the appropriate LuminanceSource object based on the format
   * of the preview buffers, as described by Camera.Parameters.
   *
   * @param data A preview frame.
   * @param width The width of the image.
   * @param height The height of the image.
   * @return A PlanarYUVLuminanceSource instance.
   */
  public PlanarYUVLuminanceSource buildLuminanceSource(byte[] data, int width, int height) {
    Rect rect = getFramingRectInPreview();
    int previewFormat = configManager.getPreviewFormat();
    String previewFormatString = configManager.getPreviewFormatString();
    switch (previewFormat) {
      // This is the standard Android format which all devices are REQUIRED to support.
      // In theory, it's the only one we should ever care about.
      case PixelFormat.YCbCr_420_SP:
        // This format has never been seen in the wild, but is compatible as we only care
        // about the Y channel, so allow it.
      case PixelFormat.YCbCr_422_SP:
        return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
                rect.width(), rect.height());
      default:
        // The Samsung Moment incorrectly uses this variant instead of the 'sp' version.
        // Fortunately, it too has all the Y data up front, so we can read it.
        if ("yuv420p".equals(previewFormatString)) {
          return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
                  rect.width(), rect.height());
        }
    }
    throw new IllegalArgumentException("Unsupported picture format: " +
            previewFormat + '/' + previewFormatString);
  }

  public Context getContext() {
    return context;
  }

}

3、要修改扫描界面，自己画界面可在ＶiewfinderView中修改

ＶiewfinderView.java

package com.zm.app.zxing.view;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.view.View;

import com.example.qr_codescan.R;
import com.google.zxing.ResultPoint;
import java.util.Collection;
import java.util.HashSet;

/**
 * Created by leiqi on 15-12-9.
 */
public class ViewfinderView extends View {
	private static final String TAG = "log";
	/**
	 * 刷新界面的时间
	 */
	private static final long ANIMATION_DELAY = 10L;
	private static final int OPAQUE = 0xFF;

	/**
	 * 四个绿色边角对应的长度
	 */
	private int ScreenRate;

	/**
	 * 四个绿色边角对应的宽度
	 */
	private static final int CORNER_WIDTH = 5;
	/**
	 * 扫描框中的中间线的宽度
	 */
	private static final int MIDDLE_LINE_WIDTH = 5;

	/**
	 * 扫描框中的中间线的与扫描框左右的间隙
	 */
	private static final int MIDDLE_LINE_PADDING = 5;

	/**
	 * 中间那条线每次刷新移动的距离
	 */
	private static final int SPEEN_DISTANCE = 5;

	/**
	 * 手机的屏幕密度
	 */
	private static float density;
	/**
	 * 字体大小
	 */
	private static final int TEXT_SIZE = 18;
	private static final int TEXT_SIZE1 = 22;
	/**
	 * 字体距离扫描框下面的距离
	 */
	private static final int TEXT_PADDING_TOP = 30;

	/**
	 * 画笔对象的引用
	 */
	private Paint paint;

	/**
	 * 中间滑动线的最顶端位置
	 */
	private int slideTop;

	/**
	 * 中间滑动线的最底端位置
	 */
	private int slideBottom;

	/**
	 * 将扫描的二维码拍下来，这里没有这个功能，暂时不考虑
	 */
	private Bitmap resultBitmap;
	private final int maskColor;
	private final int resultColor;

	private final int resultPointColor;
	private Collection possibleResultPoints;
	private Collection lastPossibleResultPoints;

	boolean isFirst;

	public ViewfinderView(Context context, AttributeSet attrs) {
		super(context, attrs);

		density = context.getResources().getDisplayMetrics().density;
		//将像素转换成dp
		ScreenRate = (int) (20 * density);

		paint = new Paint();
		Resources resources = getResources();
		maskColor = resources.getColor(R.color.viewfinder_mask);
		resultColor = resources.getColor(R.color.result_view);

		resultPointColor = resources.getColor(R.color.possible_result_points);
		possibleResultPoints = new HashSet(5);
	}

	@Override
	public void onDraw(Canvas canvas) {
		//中间的扫描框，你要修改扫描框的大小，去CameraManager里面修改
		Rect frame = com.zm.app.zxing.camera.CameraManager.get().getFramingRect();
		if (frame == null) {
			return;
		}

		//初始化中间线滑动的最上边和最下边
		if (!isFirst) {
			isFirst = true;
			slideTop = frame.top;
			slideBottom = frame.bottom;
		}

		//获取屏幕的宽和高
		int width = canvas.getWidth();
		int height = canvas.getHeight();

		paint.setColor(resultBitmap != null ? resultColor : maskColor);

		//画出扫描框外面的阴影部分，共四个部分，扫描框的上面到屏幕上面，扫描框的下面到屏幕下面
		//扫描框的左边面到屏幕左边，扫描框的右边到屏幕右边
		canvas.drawRect(0, 0, width, frame.top, paint);
		canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
		canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1,
				paint);
		canvas.drawRect(0, frame.bottom + 1, width, height, paint);


		if (resultBitmap != null) {
			// Draw the opaque result bitmap over the scanning rectangle
			paint.setAlpha(OPAQUE);
			canvas.drawBitmap(resultBitmap, frame.left, frame.top, paint);
		} else {
//			//画扫描框上面的字
//			paint.setColor(Color.rgb(255,255,255));
//			paint.setTextSize(TEXT_SIZE1 * density);
//			paint.setAlpha(0x40);
//			paint.setTypeface(Typeface.create("System", Typeface.BOLD));
//			canvas.drawText(getResources().getString(R.string.Return_car), frame.left, (float) (frame.top - (float) TEXT_PADDING_TOP * density), paint);
			//画扫描框边上的角，总共8个部分
			paint.setColor(Color.rgb(33,134,116));
			canvas.drawRect(frame.left, frame.top, frame.left + ScreenRate,
					frame.top + CORNER_WIDTH, paint);
			canvas.drawRect(frame.left, frame.top, frame.left + CORNER_WIDTH, frame.top
					+ ScreenRate, paint);
			canvas.drawRect(frame.right - ScreenRate, frame.top, frame.right,
					frame.top + CORNER_WIDTH, paint);
			canvas.drawRect(frame.right - CORNER_WIDTH, frame.top, frame.right, frame.top
					+ ScreenRate, paint);
			canvas.drawRect(frame.left, frame.bottom - CORNER_WIDTH, frame.left
					+ ScreenRate, frame.bottom, paint);
			canvas.drawRect(frame.left, frame.bottom - ScreenRate,
					frame.left + CORNER_WIDTH, frame.bottom, paint);
			canvas.drawRect(frame.right - ScreenRate, frame.bottom - CORNER_WIDTH,
					frame.right, frame.bottom, paint);
			canvas.drawRect(frame.right - CORNER_WIDTH, frame.bottom - ScreenRate,
					frame.right, frame.bottom, paint);


			//绘制中间的线,每次刷新界面，中间的线往下移动SPEEN_DISTANCE
			slideTop += SPEEN_DISTANCE;
			if (slideTop >= frame.bottom) {
				slideTop = frame.top;
			}
			canvas.drawRect(frame.left + MIDDLE_LINE_PADDING, slideTop - MIDDLE_LINE_WIDTH / 2, frame.right - MIDDLE_LINE_PADDING, slideTop + MIDDLE_LINE_WIDTH / 2, paint);


			//画扫描框下面的字
			paint.setColor(Color.WHITE);
			paint.setTextSize(TEXT_SIZE * density);
			paint.setAlpha(0x40);
			paint.setTypeface(Typeface.create("System", Typeface.BOLD));
			canvas.drawText(getResources().getString(R.string.scan_text), frame.left, (float) (frame.bottom + (float) TEXT_PADDING_TOP * density), paint);


			Collection currentPossible = possibleResultPoints;
			Collection currentLast = lastPossibleResultPoints;
			if (currentPossible.isEmpty()) {
				lastPossibleResultPoints = null;
			} else {
				possibleResultPoints = new HashSet(5);
				lastPossibleResultPoints = currentPossible;
				paint.setAlpha(OPAQUE);
				paint.setColor(resultPointColor);
				for (ResultPoint point : currentPossible) {
					canvas.drawCircle(frame.left + point.getX(), frame.top
							+ point.getY(), 6.0f, paint);
				}
			}
			if (currentLast != null) {
				paint.setAlpha(OPAQUE / 2);
				paint.setColor(resultPointColor);
				for (ResultPoint point : currentLast) {
					canvas.drawCircle(frame.left + point.getX(), frame.top
							+ point.getY(), 3.0f, paint);
				}
			}


			//只刷新扫描框的内容，其他地方不刷新
			postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top,
					frame.right, frame.bottom);

		}
	}

	public void drawViewfinder() {
		resultBitmap = null;
		invalidate();
	}

	/**
	 * Draw a bitmap with the result points highlighted instead of the live
	 * scanning display.
	 *
	 * @param barcode An image of the decoded barcode.
	 */
	public void drawResultBitmap(Bitmap barcode) {
		resultBitmap = barcode;
		invalidate();
	}

	public void addPossibleResultPoint(ResultPoint point) {
		possibleResultPoints.add(point);
	}

}

４、打开关闭闪光灯

打开关闭闪光灯直接调用

CameraManager.get().openLight();

CameraManager.get().offLight();

public void openLight(){
    if (camera != null) {
      Camera.Parameters parameter;
      parameter = camera.getParameters();
      parameter.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
      camera.setParameters(parameter);
    }
  }
  public void offLight(){
    if (camera != null) {
      Camera.Parameters parameter;
      parameter = camera.getParameters();
      parameter.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
      camera.setParameters(parameter);
    }
  }