Customize camera view for Android using zbar

Question

I am new to Android development. My application must activate the camera to scan a QR code and decode it into a string. This works great, but I have one more requirement: to present the camera in a frame and with a logo in one of the corners. I did not find a suitable API in zbar sdk to make a frame and attach a logo. This is my code:

ZBarScannerActivity.java:

package com.myCompany.android; import android.app.Activity; import android.content.Intent; import android.content.pm.PackageManager; import android.hardware.Camera; import android.media.MediaPlayer; import android.media.MediaPlayer.OnCompletionListener; import android.os.Bundle; import android.os.Handler; import android.text.TextUtils; import android.util.Log; import android.view.Menu; import android.view.View; import android.view.Window; import android.view.WindowManager; import android.widget.Toast; 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); // 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, Config.ENABLE, 1); } //test customization } } @Override protected void onResume() { super.onResume(); // Open the default ie the first rear facing camera. mCamera = Camera.open(); mPreviewing = true; mPreview.setCamera(mCamera); } @Override protected void onPause() { super.onPause(); // Because the Camera object is a shared resource, it 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(); mPreviewing = false; mCamera = null; } } 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); } }; public void launchQRScanner(View v) { if (isCameraAvailable()) { //Toast.makeText(this, "Analyzing Image", Toast.LENGTH_LONG).show(); Intent intent = new Intent(this, ZBarScannerActivity.class); intent.putExtra(ZBarConstants.SCAN_MODES, new int[]{Symbol.QRCODE}); startActivityForResult(intent, ZBAR_QR_SCANNER_REQUEST); } else { Toast.makeText(this, "Camera Unavailable", Toast.LENGTH_SHORT).show(); } } public boolean isCameraAvailable() { PackageManager pm = getPackageManager(); return pm.hasSystemFeature(PackageManager.FEATURE_CAMERA); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. //getMenuInflater().inflate(R.menu.activity_qrimport_token, menu); return true; } /* @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode) { case ZBAR_SCANNER_REQUEST: Toast.makeText(this, data.getStringExtra(ZBarConstants.SCAN_RESULT), Toast.LENGTH_LONG).show(); break; case ZBAR_QR_SCANNER_REQUEST: playSound(); if (resultCode == RESULT_OK) { Toast.makeText(this, data.getStringExtra(ZBarConstants.SCAN_RESULT), Toast.LENGTH_LONG).show(); Toast.makeText(this, "Scan Result = " + data.getStringExtra(ZBarConstants.SCAN_RESULT), Toast.LENGTH_SHORT).show(); // put whatever you want to do with the code here //TextView tv = new TextView(this); //tv.setText(data.getStringExtra(ZBarConstants.SCAN_RESULT)); Log.d("Data",""+data.getStringExtra(ZBarConstants.SCAN_RESULT)); //setContentView(tv); } break; } }*/ /*private void playSound() { MediaPlayer mp = MediaPlayer.create(getBaseContext(), R.raw.camera_shutter); mp.start(); mp.setOnCompletionListener(new OnCompletionListener() { @Override public void onCompletion(MediaPlayer mp) { mp.release(); } }); }*/ } 

CameraPreview.java:

 package com.myCompany.android; 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; class CameraPreview extends ViewGroup implements SurfaceHolder.Callback { private final String TAG = "CameraPreview"; SurfaceView mSurfaceView; SurfaceHolder mHolder; Size mPreviewSize; List<Size> mSupportedPreviewSizes; Camera mCamera; PreviewCallback mPreviewCallback; AutoFocusCallback mAutoFocusCallback; CameraPreview(Context context, PreviewCallback previewCallback, AutoFocusCallback autoFocusCb) { super(context); mPreviewCallback = previewCallback; mAutoFocusCallback = autoFocusCb; mSurfaceView = new SurfaceView(context); addView(mSurfaceView); // Install a SurfaceHolder.Callback so we get notified when the // underlying surface is created and destroyed. mHolder = mSurfaceView.getHolder(); mHolder.addCallback(this); mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } public void setCamera(Camera camera) { mCamera = camera; if (mCamera != null) { mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes(); requestLayout(); } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // We purposely disregard child measurements because act as a // wrapper to a SurfaceView that centers the camera preview instead // of stretching it. final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec); final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec); setMeasuredDimension(width, height); if (mSupportedPreviewSizes != null) { mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height); } } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { if (changed && getChildCount() > 0) { final View child = getChildAt(0); final int width = r - l; final int height = b - t; int previewWidth = width; int previewHeight = height; if (mPreviewSize != null) { previewWidth = mPreviewSize.width; previewHeight = mPreviewSize.height; } // Center the child SurfaceView within the parent. if (width * previewHeight > height * previewWidth) { final int scaledChildWidth = previewWidth * height / previewHeight; child.layout((width - scaledChildWidth) / 2, 0, (width + scaledChildWidth) / 2, height); } else { final int scaledChildHeight = previewHeight * width / previewWidth; child.layout(0, (height - scaledChildHeight) / 2, width, (height + scaledChildHeight) / 2); } } } public void surfaceCreated(SurfaceHolder holder) { // The Surface has been created, acquire the camera and tell it where // to draw. try { if (mCamera != null) { mCamera.setPreviewDisplay(holder); } } catch (IOException exception) { Log.e(TAG, "IOException caused by setPreviewDisplay()", exception); } } public void surfaceDestroyed(SurfaceHolder holder) { // Surface will be destroyed when we return, so stop the preview. if (mCamera != null) { mCamera.cancelAutoFocus(); mCamera.stopPreview(); } } private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) { final double ASPECT_TOLERANCE = 0.1; double targetRatio = (double) w / h; if (sizes == null) return null; Size optimalSize = null; double minDiff = Double.MAX_VALUE; int targetHeight = h; // Try to find an size match aspect ratio and size for (Size size : sizes) { double ratio = (double) size.width / size.height; if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue; if (Math.abs(size.height - targetHeight) < minDiff) { optimalSize = size; minDiff = Math.abs(size.height - targetHeight); } } // Cannot find the one match the aspect ratio, ignore the requirement if (optimalSize == null) { minDiff = Double.MAX_VALUE; for (Size size : sizes) { if (Math.abs(size.height - targetHeight) < minDiff) { optimalSize = size; minDiff = Math.abs(size.height - targetHeight); } } } return optimalSize; } public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { if (holder.getSurface() == null){ // preview surface does not exist return; } // Now that the size is known, set up the camera parameters and begin // the preview. Camera.Parameters parameters = mCamera.getParameters(); parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height); requestLayout(); mCamera.setParameters(parameters); mCamera.setPreviewCallback(mPreviewCallback); mCamera.startPreview(); mCamera.autoFocus(mAutoFocusCallback); } } 

How to set up camera view for Android? I saw some of the suggested solutions for the iPhone, but the zbar API for Android is completely different and much smaller. I would appreciate any idea / hint ...

Answer 1

To represent the frame in cameraview, add the image to the frame (camerapreview) in main.xml.

  <FrameLayout android:id="@+id/cameraPreview" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_weight="1" > <ImageView android:id="@+id/imageView1" android:layout_width="fill_parent" android:layout_height="fill_parent" android:alpha="0.6" android:src="@drawable/overlay" /> </FrameLayout> 

Use this code to make the frame (image) visible. Since the frame (image) is already present in the framelayout in main.xml, we need to remove it first.

  FrameLayout preview = (FrameLayout)findViewById(R.id.cameraPreview); ImageView iv=(ImageView) findViewById(R.id.imageView1); preview.addView(mPreview); preview.removeView(iv); preview.addView(iv); 

To scan the camera only from your frame, you need to use setCrop (). Adjust the size of the camera in the frame.

  barcode.setData(data); //this is in portrait mode //barcode.setCrop(left,top,width,height). barcode.setCrop(100,230,600,10); 

It worked for me and hope it solves your problem. Please excuse me for my grammatical errors. Thanks.

Answer 2

It seems to me easier than you thought:

In the code example provided by the ZBar guy, there are those two lines in the onCreate () method:

 FrameLayout preview = (FrameLayout) findViewById(R.id.cameraPreview); preview.addView(mPreview); 

who are responsible for adding a “preview” to the camerPreview layout.

Find the specified codes in the code, create a new ImageView and add it to the preview layout as follows:

 ImageView v = new ImageView(this); v.setImageResource(R.drawable.icon); preview.addView(v); 

Adjust the size and position of your view v, and you're done!

Answer 3

I ran into the same problem. The solution simply adds CameraPrevie to your xml inside frameLayout, and right after that the image you want to place on top of it.

eg:.

  <FrameLayout android:id="@+id/captionFrame" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginBottom="20dp" android:layout_marginTop="50dp" > <FrameLayout android:id="@+id/cameraPreview" android:layout_width="300dp" android:layout_height="200dp" android:layout_gravity="center" android:paddingLeft="-5dp" > </FrameLayout> <ImageView android:id="@+id/watermark" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="right|bottom" android:src="@drawable/watermark" /> </FrameLayout> 

and fill it out from your activity:

 Camera mCamera = getCameraInstance(); ImageScanner scanner = new ImageScanner(); scanner.setConfig(0, Config.X_DENSITY, 3); scanner.setConfig(0, Config.Y_DENSITY, 3); CameraPreview mPreview = new CameraPreview(this, mCamera, null, autoFocusCallB); FrameLayout preview = (FrameLayout)findViewById(R.id.cameraPreview); preview.addView(mPreview);