Java tutorial
/* * 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.jwetherell.quick_response_code; import android.app.Activity; import android.content.Intent; 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.support.v4.app.Fragment; import android.util.Log; import android.view.KeyEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.view.Window; import android.view.WindowManager; import android.widget.TextView; import android.widget.Toast; import com.google.zxing.BarcodeFormat; import com.google.zxing.Result; import com.google.zxing.ResultPoint; import com.jwetherell.quick_response_code.camera.CameraManager; import com.jwetherell.quick_response_code.result.ResultHandler; import com.jwetherell.quick_response_code.result.ResultHandlerFactory; import java.io.IOException; import java.util.Collection; /** * Example Decoder Activity. * * @author Justin Wetherell (phishman3579@gmail.com) */ public class DecoderActivity extends Activity implements IDecoderActivity, SurfaceHolder.Callback { private static final String TAG = DecoderActivity.class.getSimpleName(); public static final String EXTRA_TOAST_MESSAGE = "toastMessage"; protected DecoderActivityHandler handler = null; protected ViewfinderView viewfinderView = null; protected CameraManager cameraManager = null; protected boolean hasSurface = false; protected Collection<BarcodeFormat> decodeFormats = null; protected String characterSet = null; protected TextView statusView; public static void start(Activity activity, int requestCode) { start(activity, requestCode, null); } public static void start(Activity activity, int requestCode, String toastMessage) { final Intent intent = new Intent(activity, DecoderActivity.class); intent.putExtra(EXTRA_TOAST_MESSAGE, toastMessage); activity.startActivityForResult(intent, requestCode); } public static void start(Fragment fragment, int requestCode) { start(fragment, requestCode, null); } public static void start(Fragment fragment, int requestCode, String toastMessage) { final Intent intent = new Intent(fragment.getActivity(), DecoderActivity.class); intent.putExtra(EXTRA_TOAST_MESSAGE, toastMessage); fragment.startActivityForResult(intent, requestCode); } @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.decoder); Window window = getWindow(); window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); statusView = (TextView) findViewById(R.id.status_view); Bundle extras = getIntent().getExtras(); if (extras != null) { String toastMessage = extras.getString(EXTRA_TOAST_MESSAGE); if (toastMessage != null) { Toast.makeText(getApplicationContext(), toastMessage, Toast.LENGTH_LONG).show(); getIntent().removeExtra(EXTRA_TOAST_MESSAGE); } } handler = null; hasSurface = false; } @Override protected void onResume() { super.onResume(); // CameraManager must be initialized here, not in onCreate(). if (cameraManager == null) { cameraManager = new CameraManager(getApplication()); } if (viewfinderView == null) { viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view); viewfinderView.setCameraManager(cameraManager); } showScanner(); SurfaceView surfaceView = (SurfaceView) 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); } } @Override protected void onPause() { super.onPause(); if (handler != null) { handler.quitSynchronously(); handler = null; } cameraManager.closeDriver(); if (!hasSurface) { SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view); SurfaceHolder surfaceHolder = surfaceView.getHolder(); surfaceHolder.removeCallback(this); } } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_FOCUS || keyCode == KeyEvent.KEYCODE_CAMERA) { // Handle these events so they don't launch the Camera app return true; } return super.onKeyDown(keyCode, event); } @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) { // Ignore } @Override public ViewfinderView getViewfinder() { return viewfinderView; } @Override public Handler getHandler() { return handler; } @Override public CameraManager getCameraManager() { return cameraManager; } @Override public void handleDecode(Result rawResult, Bitmap barcode) { drawResultPoints(barcode, rawResult); if (getCallingActivity() != null) { ResultHandler resultHandler = ResultHandlerFactory.makeResultHandler(this, rawResult); CharSequence charResult = resultHandler.getDisplayContents(); String displayContents = charResult.toString(); Intent result = new Intent(); result.putExtra("result", displayContents); setResult(Activity.RESULT_OK, result); finish(); } } protected void drawResultPoints(Bitmap barcode, Result rawResult) { ResultPoint[] points = rawResult.getResultPoints(); if (points != null && points.length > 0) { Canvas canvas = new Canvas(barcode); Paint paint = new Paint(); paint.setColor(getResources().getColor(R.color.result_image_border)); paint.setStrokeWidth(3.0f); paint.setStyle(Paint.Style.STROKE); Rect border = new Rect(2, 2, barcode.getWidth() - 2, barcode.getHeight() - 2); canvas.drawRect(border, paint); paint.setColor(getResources().getColor(R.color.result_points)); if (points.length == 2) { paint.setStrokeWidth(4.0f); drawLine(canvas, paint, points[0], points[1]); } 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]); drawLine(canvas, paint, points[2], points[3]); } else { paint.setStrokeWidth(10.0f); for (ResultPoint point : points) { canvas.drawPoint(point.getX(), point.getY(), paint); } } } } protected static void drawLine(Canvas canvas, Paint paint, ResultPoint a, ResultPoint b) { canvas.drawLine(a.getX(), a.getY(), b.getX(), b.getY(), paint); } protected void showScanner() { viewfinderView.setVisibility(View.VISIBLE); } protected void initCamera(SurfaceHolder surfaceHolder) { try { cameraManager.openDriver(surfaceHolder); // Creating the handler starts the preview, which can also throw a // RuntimeException. if (handler == null) { handler = new DecoderActivityHandler(this, decodeFormats, characterSet, cameraManager); } } 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); } } }