在Android上使用ZXing识别条码/二维码

越来越多的手机具备自动对焦的拍摄功能，这也意味着这些手机可以具备条码扫描的功能.......手机具备条码扫描的功能，可以优化购物流程，快速存储电子名片(二维码)等。

????? 本文使用ZXing 1.6实现条码/二维码识别。ZXing是个很经典的条码/二维码识别的开源类库，long long ago，就有开发者在J2ME上使用ZXing了，不过要支持JSR-234规范(自动对焦)的手机才能发挥其威力，而目前已经有不少Android手机具备自动对焦的功能。

本文代码运行的结果如下，使用91手机助手截图时，无法截取SurfaceView的实时图像：

本文使用了ZXing1.6的core，即把\zxing-1.6\core\下的src复制覆盖工程的src；另外还要使用到\zxing-1.6\android\下的PlanarYUVLuminanceSource.java。?

PS：\zxing-1.6\android\ 是BarcodeScanner的源码，本文程序相当于BarcodeScanner的精简版，只保留最基本的识别功能。

源码目录结果如下图，ChecksumException.java下面还有很多源文件，截图尚未列出：

main.xml源码如下，main.xml必须要用到FrameLayout才能重叠控件实现“范围框”的效果：

<?xml version="1.0" encoding="utf-8"?><FrameLayout android:id="@+id/FrameLayout01"android:layout_width="fill_parent" android:layout_height="fill_parent"xmlns:android="http://schemas.android.com/apk/res/android"><SurfaceView android:layout_height="fill_parent"android:id="@+id/sfvCamera" android:layout_width="fill_parent"></SurfaceView><RelativeLayout android:id="@+id/RelativeLayout01"android:layout_height="fill_parent" android:layout_width="fill_parent"><ImageView android:id="@+id/ImageView01"android:layout_height="100dip" android:layout_width="160dip"></ImageView><View android:layout_centerVertical="true"android:layout_centerHorizontal="true" android:layout_width="300dip"android:background="#55FF6666" android:id="@+id/centerView"android:layout_height="180dip"></View><TextView android:layout_centerHorizontal="true"android:layout_width="wrap_content" android:layout_below="@+id/centerView"android:layout_height="wrap_content" android:text="Scanning..."android:id="@+id/txtScanResult" android:textColor="#FF000000"></TextView></RelativeLayout></FrameLayout>

testCamera.java是主类，负责控制Camera和对图像做解码，源码如下：

package com.testCamera;import java.util.Timer;import java.util.TimerTask;import com.google.zxing.BinaryBitmap;import com.google.zxing.MultiFormatReader;import com.google.zxing.Result;import com.google.zxing.Android.PlanarYUVLuminanceSource;import com.google.zxing.common.HybridBinarizer;import android.app.Activity;import android.graphics.Bitmap;import android.hardware.Camera;import android.os.Bundle;import android.view.SurfaceView;import android.view.View;import android.widget.ImageView;import android.widget.TextView;public class testCamera extends Activity {/** Called when the activity is first created. */private SurfaceView sfvCamera;private SFHCamera sfhCamera;private ImageView imgView;private View centerView;private TextView txtScanResult;private Timer mTimer;private MyTimerTask mTimerTask;// 按照标准HVGAfinal static int width = 480;final static int height = 320;int dstLeft, dstTop, dstWidth, dstHeight;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);this.setTitle("Android条码/二维码识别Demo-----hellogv");imgView = (ImageView) this.findViewById(R.id.ImageView01);centerView = (View) this.findViewById(R.id.centerView);sfvCamera = (SurfaceView) this.findViewById(R.id.sfvCamera);sfhCamera = new SFHCamera(sfvCamera.getHolder(), width, height,previewCallback);txtScanResult=(TextView)this.findViewById(R.id.txtScanResult);// 初始化定时器mTimer = new Timer();mTimerTask = new MyTimerTask();mTimer.schedule(mTimerTask, 0, 80);}class MyTimerTask extends TimerTask {@Overridepublic void run() {if (dstLeft == 0) {//只赋值一次dstLeft = centerView.getLeft() * width/ getWindowManager().getDefaultDisplay().getWidth();dstTop = centerView.getTop() * height/ getWindowManager().getDefaultDisplay().getHeight();dstWidth = (centerView.getRight() - centerView.getLeft())* width/ getWindowManager().getDefaultDisplay().getWidth();dstHeight = (centerView.getBottom() - centerView.getTop())* height/ getWindowManager().getDefaultDisplay().getHeight();}sfhCamera.AutoFocusAndPreviewCallback();}}/** * 自动对焦后输出图片 */private Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() {@Overridepublic void onPreviewFrame(byte[] data, Camera arg1) {//取得指定范围的帧的数据PlanarYUVLuminanceSource source = new PlanarYUVLuminanceSource(data, width, height, dstLeft, dstTop, dstWidth, dstHeight);//取得灰度图Bitmap mBitmap = source.renderCroppedGreyscaleBitmap();//显示灰度图imgView.setImageBitmap(mBitmap);BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));MultiFormatReader reader = new MultiFormatReader();try {Result result = reader.decode(bitmap);String strResult = "BarcodeFormat:"+ result.getBarcodeFormat().toString() + " text:"+ result.getText();txtScanResult.setText(strResult);} catch (Exception e) {txtScanResult.setText("Scanning");}}};}

SFHCamera.java是Camera控制类，源码如下：

package com.testCamera;import java.io.IOException;import android.graphics.PixelFormat;import android.hardware.Camera;import android.util.Log;import android.view.SurfaceHolder;public class SFHCamera implements SurfaceHolder.Callback{private SurfaceHolder holder = null;private Camera mCamera; private int width,height; private Camera.PreviewCallback previewCallback; public SFHCamera(SurfaceHolder holder,int w,int h,Camera.PreviewCallback previewCallback) {this.holder = holder; this.holder.addCallback(this); this.holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); width=w; height=h; this.previewCallback=previewCallback;}@Overridepublic void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {Camera.Parameters parameters = mCamera.getParameters(); parameters.setPreviewSize(width, height);//设置尺寸 parameters.setPictureFormat(PixelFormat.JPEG); mCamera.setParameters(parameters); mCamera.startPreview();//开始预览 Log.e("Camera","surfaceChanged");}@Overridepublic void surfaceCreated(SurfaceHolder arg0) {mCamera = Camera.open();//启动服务 try { mCamera.setPreviewDisplay(holder);//设置预览 Log.e("Camera","surfaceCreated"); } catch (IOException e) { mCamera.release();//释放 mCamera = null; }}@Overridepublic void surfaceDestroyed(SurfaceHolder arg0) {mCamera.setPreviewCallback(null);mCamera.stopPreview();//停止预览 mCamera = null; Log.e("Camera","surfaceDestroyed");}/** * 自动对焦并回调Camera.PreviewCallback */public void AutoFocusAndPreviewCallback(){if(mCamera!=null)mCamera.autoFocus(mAutoFocusCallBack);}/** * 自动对焦 */ private Camera.AutoFocusCallback mAutoFocusCallBack = new Camera.AutoFocusCallback() { @Override public void onAutoFocus(boolean success, Camera camera) { if (success) { //对焦成功，回调Camera.PreviewCallback mCamera.setOneShotPreviewCallback(previewCallback); } } }; }

其中testCamera.java的Camera.PreviewCallback previewCallback?是整个程序的逻辑核心，作为回调函数给SFHCamera.java的内部Camera类调用。