Android使用ZXing类库进行条码/二维码识别（转）
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：
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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：
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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代码
<?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.testbarcode.android;
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.testbarcode.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HVGA??
??? final static int width = 480;??
??? final static int height = 320;??
??? int dstLeft, dstTop, dstWidth, dstHeight;??
??? @Override?
??? public 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 {??
??????? @Override?
??????? public 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() {??
??????? @Override?
??????? public 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,false);??
??????????? //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.testbarcode.android;
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;??
??? }??
??????
??? @Override?
??? public 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");??
??? }??
??? @Override?
??? public 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;????
??????? }??
??????????
??? }??
??? @Override?
??? public 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);???
??????????? }????
??????? }????
??? };??
??????
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}?
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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。