Java tutorial
package com.welcu.android.zxingfragmentlib; import android.content.SharedPreferences; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.preference.PreferenceManager; import android.support.v4.app.Fragment; import android.util.Log; import android.view.KeyEvent; import android.view.LayoutInflater; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.view.WindowManager; import com.google.zxing.BarcodeFormat; import com.google.zxing.DecodeHintType; import com.google.zxing.Result; import com.google.zxing.ResultPoint; import com.welcu.android.zxingfragmentlib.camera.CameraManager; import java.io.IOException; import java.util.Collection; import java.util.Map; /* * 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. */ /** * 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 */ public class BarCodeScannerFragment extends Fragment implements SurfaceHolder.Callback, IConstants { private static final String TAG = BarCodeScannerFragment.class.getSimpleName(); private static final long DEFAULT_INTENT_RESULT_DURATION_MS = 1500L; private static final long BULK_MODE_SCAN_DELAY_MS = 1000L; public static final int HISTORY_REQUEST_CODE = 0x0000bacc; private CameraManager cameraManager; private BarCodeScannerHandler handler; private Result savedResultToShow; private ViewfinderView viewfinderView; private Result lastResult; private boolean hasSurface; private Collection<BarcodeFormat> decodeFormats; private Map<DecodeHintType, ?> decodeHints; private String characterSet; private InactivityTimer inactivityTimer; private BeepManager beepManager; private AmbientLightManager ambientLightManager; private IResultCallback mCallBack; private Rect customFramingRect; ViewfinderView getViewfinderView() { return viewfinderView; } public Handler getHandler() { return handler; } CameraManager getCameraManager() { return cameraManager; } @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); hasSurface = false; inactivityTimer = new InactivityTimer(this.getActivity()); beepManager = new BeepManager(this.getActivity()); ambientLightManager = new AmbientLightManager(this.getActivity()); PreferenceManager.setDefaultValues(this.getActivity(), R.xml.preferences, false); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstance) { View view = inflater.inflate(R.layout.capture, container, false); Window window = getActivity().getWindow(); window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); return view; } @Override public void onResume() { super.onResume(); startScan(); } @Override public void onPause() { stopScan(); super.onPause(); } /** * Initializes the camera and viewfinderView. */ public void startScan() { if (cameraManager != null) { Log.e(TAG, "startScan: scan already started."); return; } // 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().getApplication(), getView()); viewfinderView = (ViewfinderView) getView().findViewById(R.id.viewfinder_view); viewfinderView.setCameraManager(cameraManager); handler = null; lastResult = null; SurfaceView surfaceView = (SurfaceView) getView().findViewById(R.id.preview_view); 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); } if (customFramingRect != null) { cameraManager.setManualFramingRect(customFramingRect); } beepManager.updatePrefs(); ambientLightManager.start(cameraManager); inactivityTimer.onResume(); SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this.getActivity()); decodeFormats = null; characterSet = null; } public void stopScan() { if (cameraManager == null) { Log.e(TAG, "stopScan: scan already stopped"); return; } if (handler != null) { handler.quitSynchronously(); handler = null; } inactivityTimer.onPause(); ambientLightManager.stop(); cameraManager.closeDriver(); cameraManager = null; if (!hasSurface) { SurfaceView surfaceView = (SurfaceView) getView().findViewById(R.id.preview_view); SurfaceHolder surfaceHolder = surfaceView.getHolder(); surfaceHolder.removeCallback(this); } } public void setTorch(boolean state) { if (cameraManager != null) { cameraManager.setTorch(state); } } public void setTorchOn() { setTorch(true); } public void setTorchOff() { setTorch(false); } @Override public void onDestroy() { inactivityTimer.shutdown(); super.onDestroy(); } // @Override public boolean onKeyDown(int keyCode, KeyEvent event) { switch (keyCode) { case KeyEvent.KEYCODE_FOCUS: case KeyEvent.KEYCODE_CAMERA: // Handle these events so they don't launch the Camera app return true; // Use volume up/down to turn on light case KeyEvent.KEYCODE_VOLUME_DOWN: // cameraManager.setTorch(false); setTorchOff(); return true; case KeyEvent.KEYCODE_VOLUME_UP: setTorchOn(); return true; } return false; //super.onKeyDown(keyCode, event); } 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, DECODE_SUCCEDED, 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) { } public void setmCallBack(IResultCallback mCallBack) { this.mCallBack = mCallBack; } public void setFramingRect(int width, int height, int left, int top) { setFramingRect(new Rect(left, top, left + width, top + height)); } public void setFramingRect(Rect rect) { this.customFramingRect = rect; if (cameraManager != null) { cameraManager.setManualFramingRect(rect); } } public interface IResultCallback { void result(Result lastResult); } /** * 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(); lastResult = rawResult; beepManager.playBeepSoundAndVibrate(); drawResultPoints(barcode, scaleFactor, rawResult); if (mCallBack != null) { mCallBack.result(rawResult); } restartPreviewAfterDelay(500L); } private boolean isPortrait() { if (getView().getWidth() < getView().getHeight()) return true; else return false; } /** * 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 && barcode != null) { Canvas canvas = new Canvas(barcode); Paint paint = new Paint(); paint.setColor(getResources().getColor(R.color.result_points)); 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); } } if (isPortrait()) { Log.d(TAG, "rotating results canvas"); canvas.rotate(90); } } } 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); } } private void sendReplyMessage(int id, Object arg, long delayMS) { Message message = Message.obtain(handler, id, arg); if (delayMS > 0L) { handler.sendMessageDelayed(message, delayMS); } else { handler.sendMessage(message); } } 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 BarCodeScannerHandler(this, decodeFormats, decodeHints, characterSet, cameraManager); } decodeOrStoreSavedBitmap(null, null); } catch (IOException ioe) { Log.w(TAG, ioe); } 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); } } public void restartPreviewAfterDelay(long delayMS) { if (handler != null) { handler.sendEmptyMessageDelayed(RESTART_PREVIEW, delayMS); } } public void drawViewfinder() { viewfinderView.drawViewfinder(); } }