Java tutorial
/* * Copyright (C) 2008 ZXing authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.abhi.barcode.frag.libv2; import java.io.IOException; import java.util.Collection; import java.util.Map; import android.app.AlertDialog; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.support.v4.app.Fragment; import android.util.Log; import android.view.LayoutInflater; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.view.ViewGroup; import android.widget.FrameLayout; import android.widget.FrameLayout.LayoutParams; import com.google.zxing.BarcodeFormat; import com.google.zxing.DecodeHintType; import com.google.zxing.Result; import com.google.zxing.ResultPoint; import com.google.zxing.client.android.AmbientLightManager; import com.google.zxing.client.android.CaptureFragmentHandler; import com.google.zxing.client.android.DecodeFormatManager; import com.google.zxing.client.android.FinishListener; import com.google.zxing.client.android.InactivityTimer; import com.google.zxing.client.android.ViewfinderView; import com.google.zxing.client.android.camera.CameraManager; import com.google.zxing.client.android.result.ResultHandlerFactory; /** * This activity opens the camera and does the actual scanning on a background * thread. It draws a viewfinder to help the user place the barcode correctly, * shows feedback as the image processing is happening, and then overlays the * results when a scan is successful. * * @author dswitkin@google.com (Daniel Switkin) * @author Sean Owen * @author Abhinava Srivastava */ public final class BarcodeFragment extends Fragment implements SurfaceHolder.Callback { private static final String TAG = BarcodeFragment.class.getSimpleName(); private static final long BULK_MODE_SCAN_DELAY_MS = 1000L; private CameraManager cameraManager; private CaptureFragmentHandler handler; private Result savedResultToShow; private ViewfinderView viewfinderView; private boolean hasSurface; private Collection<BarcodeFormat> decodeFormats; private Map<DecodeHintType, ?> decodeHints; private String characterSet; private InactivityTimer inactivityTimer; private AmbientLightManager ambientLightManager; public ViewfinderView getViewfinderView() { return viewfinderView; } public Handler getHandler() { return handler; } public CameraManager getCameraManager() { return cameraManager; } @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); hasSurface = false; } private IScanResultHandler resultHandler; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { FrameLayout frameLayout = new FrameLayout(getActivity()); FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); frameLayout.setLayoutParams(layoutParams); surfaceView = new SurfaceView(getActivity()); surfaceView.setLayoutParams(layoutParams); viewfinderView = new ViewfinderView(getActivity()); viewfinderView.setLayoutParams(layoutParams); frameLayout.addView(surfaceView); frameLayout.addView(viewfinderView); View v = frameLayout; inactivityTimer = new InactivityTimer(this.getActivity()); ambientLightManager = new AmbientLightManager(this.getActivity()); return v; } public void setDecodeFor(Collection<BarcodeFormat> decodeFormat) { this.decodeFormats = decodeFormat; } public void setDecodeFor(IScanResultHandler.MODE decodeMode) { switch (decodeMode) { case PRODUCT_MODE: this.decodeFormats = DecodeFormatManager.PRODUCT_FORMATS; break; case QR_CODE_MODE: this.decodeFormats = DecodeFormatManager.QR_CODE_FORMATS; break; case DATA_MATRIX_MODE: this.decodeFormats = DecodeFormatManager.DATA_MATRIX_FORMATS; break; case ONE_D_MODE: this.decodeFormats = DecodeFormatManager.ONE_D_FORMATS; break; } } SurfaceView surfaceView; @SuppressWarnings("deprecation") @Override public void onResume() { super.onResume(); // CameraManager must be initialized here, not in onCreate(). This is // necessary because we don't // want to open the camera driver and measure the screen size if we're // going to show the help on // first launch. That led to bugs where the scanning rectangle was the // wrong size and partially // off screen. cameraManager = new CameraManager(this.getActivity(), getView()); viewfinderView.setCameraManager(cameraManager); handler = null; resetStatusView(); SurfaceHolder surfaceHolder = surfaceView.getHolder(); if (hasSurface) { // The activity was paused but not stopped, so the surface still // exists. Therefore // surfaceCreated() won't be called, so init the camera here. initCamera(surfaceHolder); } else { // Install the callback and wait for surfaceCreated() to init the // camera. surfaceHolder.addCallback(this); surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } ambientLightManager.start(cameraManager); inactivityTimer.onResume(); characterSet = null; } @Override public void onPause() { if (handler != null) { handler.quitSynchronously(); handler = null; } inactivityTimer.onPause(); ambientLightManager.stop(); cameraManager.closeDriver(); if (!hasSurface) { SurfaceView surfaceView = this.surfaceView; SurfaceHolder surfaceHolder = surfaceView.getHolder(); surfaceHolder.removeCallback(this); } super.onPause(); } @Override public void onDestroy() { inactivityTimer.shutdown(); super.onDestroy(); } public void restart() { restartPreviewAfterDelay(BULK_MODE_SCAN_DELAY_MS); } private void decodeOrStoreSavedBitmap(Bitmap bitmap, Result result) { // Bitmap isn't used yet -- will be used soon if (handler == null) { savedResultToShow = result; } else { if (result != null) { savedResultToShow = result; } if (savedResultToShow != null) { Message message = Message.obtain(handler, IDS.id.decode_succeeded, savedResultToShow); handler.sendMessage(message); } savedResultToShow = null; } } @Override public void surfaceCreated(SurfaceHolder holder) { if (holder == null) { Log.e(TAG, "*** WARNING *** surfaceCreated() gave us a null surface!"); } if (!hasSurface) { hasSurface = true; initCamera(holder); } } @Override public void surfaceDestroyed(SurfaceHolder holder) { hasSurface = false; } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { } /** * A valid barcode has been found, so give an indication of success and show * the results. * * @param rawResult * The contents of the barcode. * @param scaleFactor * amount by which thumbnail was scaled * @param barcode * A greyscale bitmap of the camera data which was decoded. */ public void handleDecode(Result rawResult, Bitmap barcode, float scaleFactor) { inactivityTimer.onActivity(); ScanResult resultHandler = ResultHandlerFactory.parseResult(rawResult); boolean fromLiveScan = barcode != null; if (fromLiveScan) { drawResultPoints(barcode, scaleFactor, rawResult); } handleDecodeInternally(rawResult, resultHandler, barcode); } /** * Superimpose a line for 1D or dots for 2D to highlight the key features of * the barcode. * * @param barcode * A bitmap of the captured image. * @param scaleFactor * amount by which thumbnail was scaled * @param rawResult * The decoded results which contains the points to draw. */ private void drawResultPoints(Bitmap barcode, float scaleFactor, Result rawResult) { ResultPoint[] points = rawResult.getResultPoints(); if (points != null && points.length > 0) { Canvas canvas = new Canvas(barcode); Paint paint = new Paint(); paint.setColor(Color.parseColor("#c099cc00")); if (points.length == 2) { paint.setStrokeWidth(4.0f); drawLine(canvas, paint, points[0], points[1], scaleFactor); } else if (points.length == 4 && (rawResult.getBarcodeFormat() == BarcodeFormat.UPC_A || rawResult.getBarcodeFormat() == BarcodeFormat.EAN_13)) { // Hacky special case -- draw two lines, for the barcode and // metadata drawLine(canvas, paint, points[0], points[1], scaleFactor); drawLine(canvas, paint, points[2], points[3], scaleFactor); } else { paint.setStrokeWidth(10.0f); for (ResultPoint point : points) { canvas.drawPoint(scaleFactor * point.getX(), scaleFactor * point.getY(), paint); } } } } private static void drawLine(Canvas canvas, Paint paint, ResultPoint a, ResultPoint b, float scaleFactor) { if (a != null && b != null) { canvas.drawLine(scaleFactor * a.getX(), scaleFactor * a.getY(), scaleFactor * b.getX(), scaleFactor * b.getY(), paint); } } // Put up our own UI for how to handle the decoded contents. private void handleDecodeInternally(Result rawResult, ScanResult resultHandler, Bitmap barcode) { viewfinderView.setVisibility(View.GONE); if (this.resultHandler != null) { this.resultHandler.scanResult(resultHandler); } } private void initCamera(SurfaceHolder surfaceHolder) { if (surfaceHolder == null) { throw new IllegalStateException("No SurfaceHolder provided"); } if (cameraManager.isOpen()) { Log.w(TAG, "initCamera() while already open -- late SurfaceView callback?"); return; } try { cameraManager.openDriver(surfaceHolder); // Creating the handler starts the preview, which can also throw a // RuntimeException. if (handler == null) { handler = new CaptureFragmentHandler(this, decodeFormats, decodeHints, characterSet, cameraManager); } decodeOrStoreSavedBitmap(null, null); } catch (IOException ioe) { Log.w(TAG, ioe); displayFrameworkBugMessageAndExit(); } catch (RuntimeException e) { // Barcode Scanner has seen crashes in the wild of this variety: // java.?lang.?RuntimeException: Fail to connect to camera service Log.w(TAG, "Unexpected error initializing camera", e); displayFrameworkBugMessageAndExit(); } } private void displayFrameworkBugMessageAndExit() { AlertDialog.Builder builder = new AlertDialog.Builder(this.getActivity()); builder.setTitle(getString(R.string.app_name)); builder.setMessage("Sorry, the Android camera encountered a problem. You may need to restart the device."); builder.setPositiveButton("OK", new FinishListener(this.getActivity())); builder.setOnCancelListener(new FinishListener(this.getActivity())); builder.show(); } public void restartPreviewAfterDelay(long delayMS) { if (handler != null) { handler.sendEmptyMessageDelayed(IDS.id.restart_preview, delayMS); } resetStatusView(); } private void resetStatusView() { viewfinderView.setVisibility(View.VISIBLE); } public void drawViewfinder() { viewfinderView.drawViewfinder(); } public IScanResultHandler getScanResultHandler() { return resultHandler; } public void setScanResultHandler(IScanResultHandler resultHandler) { this.resultHandler = resultHandler; } }