Android ZBar bar code reader二维码

今天研究了一下，Android中怎么实现二维码的扫描功能，在网上查了一下资料，找到一个简单方便的库ZBar bar code reader。首先要添加ZBar bar库zbar.jar，如图所示

  添加权限：

 <uses-permission android:name="android.permission.CAMERA" />
     <uses-feature android:name="android.hardware.camera" />
     <uses-feature android:name="android.hardware.camera.autofocus" />

  定义一个类继承SurfaceView来预览二维码，代码：

 /** A basic Camera preview class */
 public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
     private SurfaceHolder mHolder;
     private Camera mCamera;
     private PreviewCallback previewCallback;
     private AutoFocusCallback autoFocusCallback;

     public CameraPreview(Context context, Camera camera,
                          PreviewCallback previewCb,
                          AutoFocusCallback autoFocusCb) {
         super(context);
         mCamera = camera;
         previewCallback = previewCb;
         autoFocusCallback = autoFocusCb;

         /*
          * Set camera to continuous focus if supported, otherwise use
          * software auto-focus. Only works for API level >=9.
          */
         /*
         Camera.Parameters parameters = camera.getParameters();
         for (String f : parameters.getSupportedFocusModes()) {
             if (f == Parameters.FOCUS_MODE_CONTINUOUS_PICTURE) {
                 mCamera.setFocusMode(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
                 autoFocusCallback = null;
                 break;
             }
         }
         */

         // Install a SurfaceHolder.Callback so we get notified when the
         // underlying surface is created and destroyed.
         mHolder = getHolder();
         mHolder.addCallback(this);

         // deprecated setting, but required on Android versions prior to 3.0
         mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
     }

     public void surfaceCreated(SurfaceHolder holder) {
         // The Surface has been created, now tell the camera where to draw the preview.
         try {
             mCamera.setPreviewDisplay(holder);
         } catch (IOException e) {
             Log.d("DBG", "Error setting camera preview: " + e.getMessage());
         }
     }

     public void surfaceDestroyed(SurfaceHolder holder) {
         // Camera preview released in activity
     }

     public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
         /*
          * If your preview can change or rotate, take care of those events here.
          * Make sure to stop the preview before resizing or reformatting it.
          */
         if (mHolder.getSurface() == null){
           // preview surface does not exist
           return;
         }

         // stop preview before making changes
         try {
             mCamera.stopPreview();
         } catch (Exception e){
           // ignore: tried to stop a non-existent preview
         }

         try {
             // Hard code camera surface rotation 90 degs to match Activity view in portrait
             mCamera.setDisplayOrientation(90);

             mCamera.setPreviewDisplay(mHolder);
             mCamera.setPreviewCallback(previewCallback);
             mCamera.startPreview();
             mCamera.autoFocus(autoFocusCallback);
         } catch (Exception e){
             Log.d("DBG", "Error starting camera preview: " + e.getMessage());
         }
     }
 }

  主Activity的代码：

 /* Import ZBar Class files */

 public class CameraTestActivity extends Activity
 {
     private Camera mCamera;
     private CameraPreview mPreview;
     private Handler autoFocusHandler;

     TextView scanText;
     Button scanButton;

     ImageScanner scanner;

     private boolean barcodeScanned = false;
     private boolean previewing = true;

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

     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);

         setContentView(R.layout.main);

         setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

         autoFocusHandler = new Handler();
         mCamera = getCameraInstance();

         /* Instance barcode scanner */
         scanner = new ImageScanner();
         scanner.setConfig(0, Config.X_DENSITY, 3);
         scanner.setConfig(0, Config.Y_DENSITY, 3);

         mPreview = new CameraPreview(this, mCamera, previewCb, autoFocusCB);
         FrameLayout preview = (FrameLayout)findViewById(R.id.cameraPreview);
         preview.addView(mPreview);

         scanText = (TextView)findViewById(R.id.scanText);

         scanButton = (Button)findViewById(R.id.ScanButton);

         scanButton.setOnClickListener(new OnClickListener() {
                 public void onClick(View v) {
                     if (barcodeScanned) {
                         barcodeScanned = false;
                         scanText.setText("Scanning...");
                         mCamera.setPreviewCallback(previewCb);
                         mCamera.startPreview();
                         previewing = true;
                         mCamera.autoFocus(autoFocusCB);
                     }
                 }
             });
     }

     public void onPause() {
         super.onPause();
         releaseCamera();
     }

     /** A safe way to get an instance of the Camera object. */
     public static Camera getCameraInstance(){
         Camera c = null;
         try {
             c = Camera.open();
         } catch (Exception e){
         }
         return c;
     }

     private void releaseCamera() {
         if (mCamera != null) {
             previewing = false;
             mCamera.setPreviewCallback(null);
             mCamera.release();
             mCamera = null;
         }
     }

     private Runnable doAutoFocus = new Runnable() {
             public void run() {
                 if (previewing)
                     mCamera.autoFocus(autoFocusCB);
             }
         };

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

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

                 int result = scanner.scanImage(barcode);

                 if (result != 0) {
                     previewing = false;
                     mCamera.setPreviewCallback(null);
                     mCamera.stopPreview();

                     SymbolSet syms = scanner.getResults();
                     for (Symbol sym : syms) {
                         scanText.setText("barcode result " + sym.getData());
                         barcodeScanned = true;
                     }
                 }
             }
         };

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

  以上就是使用ZBar库来扫描二维码。

 详细资料：http://sourceforge.net/p/zbar/news/2012/03/zbar-android-sdk-version-01-released/。