这些是我正在使用的类：

MainActivity.java

package com.example.sage.appp;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Toast;

import net.sourceforge.zbar.Symbol;


public class MainActivity extends Activity
{

private static final int ZBAR_SCANNER_REQUEST = 0;
private static final int ZBAR_QR_SCANNER_REQUEST = 1;

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
}

public void launchScanner(View v)
{
    if (isCameraAvailable())
    {
        Intent intent = new Intent(this,ZBarScannerActivity.class);
        startActivityForResult(intent,ZBAR_SCANNER_REQUEST);
    }
    else
    {
        Toast.makeText(this,"Rear Facing Camera Unavailable",Toast.LENGTH_SHORT).show();
    }
}

public void launchQRScanner(View v)
{
    if (isCameraAvailable())
    {
        Intent intent = new Intent(this,ZBarScannerActivity.class);
        intent.putExtra(ZBarConstants.SCAN_MODES,new int[]{Symbol.QRCODE});
        startActivityForResult(intent,Toast.LENGTH_SHORT).show();
    }
}

public boolean isCameraAvailable()
{
    PackageManager pm = getPackageManager();
    return pm.hasSystemFeature(PackageManager.FEATURE_CAMERA);
}

@Override
protected void onActivityResult(int requestCode,int resultCode,Intent data)
{
    switch (requestCode)
    {
        case ZBAR_SCANNER_REQUEST:
        case ZBAR_QR_SCANNER_REQUEST:

            if (resultCode == RESULT_OK)
            {
                Toast.makeText(this,"Scan Result = " + data.getStringExtra(ZBarConstants.SCAN_RESULT),Toast.LENGTH_SHORT).show();
            }
            else if(resultCode == RESULT_CANCELED && data != null)
            {
                String error = data.getStringExtra(ZBarConstants.ERROR_INFO);
                if(!TextUtils.isEmpty(error))
                {
                    Toast.makeText(this,error,Toast.LENGTH_SHORT).show();
                }
            }
            break;
    }
}

}

ZBarScannerActivity.java

package com.example.sage.appp;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.os.Bundle;
import android.os.Handler;
import android.text.TextUtils;
import android.view.Window;
import android.view.WindowManager;
import net.sourceforge.zbar.Config;
import net.sourceforge.zbar.Image;
import net.sourceforge.zbar.ImageScanner;
import net.sourceforge.zbar.Symbol;
import net.sourceforge.zbar.SymbolSet;
public class ZBarScannerActivity extends Activity implements
Camera.PreviewCallback,ZBarConstants {
private static final String TAG = "ZBarScannerActivity";
private CameraPreview mPreview;
private Camera mCamera;
private ImageScanner mScanner;
private Handler mAutoFocusHandler;
private boolean mPreviewing = true;

static {
    System.loadLibrary("iconv");
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if(!isCameraAvailable()) {
        // Cancel request if there is no rear-facing camera.
        cancelRequest();
        return;
    }

    // Hide the window title.
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);

    mAutoFocusHandler = new Handler();

    // Create and configure the ImageScanner;
    setupScanner();

    // Create a RelativeLayout container that will hold a SurfaceView,// and set it as the content of our activity.
    mPreview = new CameraPreview(this,this,autoFocusCB);
    setContentView(mPreview);
}

public void setupScanner() {
    mScanner = new ImageScanner();
    mScanner.setConfig(0,Config.X_DENSITY,3);
    mScanner.setConfig(0,Config.Y_DENSITY,3);

    int[] symbols = getIntent().getIntArrayExtra(SCAN_MODES);
    if (symbols != null) {
        mScanner.setConfig(Symbol.NONE,Config.ENABLE,0);
        for (int symbol : symbols) {
            mScanner.setConfig(symbol,1);
        }
    }
}

@Override
protected void onResume() {
    super.onResume();

    // Open the default i.e. the first rear facing camera.
    mCamera = Camera.open();
    if(mCamera == null) {
        // Cancel request if mCamera is null.
        cancelRequest();
        return;
    }

    mPreview.setCamera(mCamera);
    mPreview.showSurfaceView();

    mPreviewing = true;
}

@Override
protected void onPause() {
    super.onPause();

    // Because the Camera object is a shared resource,it's very
    // important to release it when the activity is paused.
    if (mCamera != null) {
        mPreview.setCamera(null);
        mCamera.cancelAutoFocus();
        mCamera.setPreviewCallback(null);
        mCamera.stopPreview();
        mCamera.release();

        // According to Jason Kuang on https://stackoverflow.com/questions/6519120/how-to-recover-camera-preview-from-sleep,// there might be surface recreation problems when the device goes to sleep. So lets just hide it and
        // recreate on resume
        mPreview.hideSurfaceView();

        mPreviewing = false;
        mCamera = null;
    }
}

public boolean isCameraAvailable() {
    PackageManager pm = getPackageManager();
    return pm.hasSystemFeature(PackageManager.FEATURE_CAMERA);
}

public void cancelRequest() {
    Intent dataIntent = new Intent();
    dataIntent.putExtra(ERROR_INFO,"Camera unavailable");
    setResult(Activity.RESULT_CANCELED,dataIntent);
    finish();
}

public void onPreviewFrame(byte[] data,Camera camera) {
    Camera.Parameters parameters = camera.getParameters();
    Camera.Size size = parameters.getPreviewSize();

    Image barcode = new Image(size.width,size.height,"Y800");
    barcode.setData(data);

    int result = mScanner.scanImage(barcode);

    if (result != 0) {
        mCamera.cancelAutoFocus();
        mCamera.setPreviewCallback(null);
        mCamera.stopPreview();
        mPreviewing = false;
        SymbolSet syms = mScanner.getResults();
        for (Symbol sym : syms) {
            String symData = sym.getData();
            if (!TextUtils.isEmpty(symData)) {
                Intent dataIntent = new Intent();
                dataIntent.putExtra(SCAN_RESULT,symData);
                dataIntent.putExtra(SCAN_RESULT_TYPE,sym.getType());
                setResult(Activity.RESULT_OK,dataIntent);
                finish();
                break;
            }
        }
    }
}
private Runnable doAutoFocus = new Runnable() {
    public void run() {
        if(mCamera != null && mPreviewing) {
            mCamera.autoFocus(autoFocusCB);
        }
    }
};

// Mimic continuous auto-focusing
Camera.AutoFocusCallback autoFocusCB = new Camera.AutoFocusCallback() {
    public void onAutoFocus(boolean success,Camera camera) {
        mAutoFocusHandler.postDelayed(doAutoFocus,1000);
    }
};

}

CameraPreview.java

package com.example.sage.appp;
import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.PreviewCallback;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import java.io.IOException;
import java.util.List;
public class CameraPreview extends ViewGroup implements SurfaceHolder.Callback
{
 private final String TAG = "CameraPreview";

SurfaceView mSurfaceView;
SurfaceHolder mHolder;
Size mPreviewSize;
List