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代码

[xml] view
plaincopy

<textarea cols="50" rows="15" name="code" class="xhtml"><?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>

</textarea>

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

Java代码



[java] view
plaincopy

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：

Java代码

[java] view
plaincopy

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);

}

}

};





}



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。

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这篇文章转自javaeye（http://17zouguo.javaeye.com/blog/857349）,程序运行起来效果不是很好，还需改进。