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：
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);
//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"
);
}
}
};
} 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); //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;
}
@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);
}
}
};
} 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; } @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。