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 piuk.blockchain.android.ui.zxing; import com.google.zxing.BarcodeFormat; import com.google.zxing.DecodeHintType; import com.google.zxing.Result; import com.google.zxing.ResultPoint; import piuk.blockchain.android.ui.zxing.camera.CameraManager; import android.support.v4.content.ContextCompat; import android.support.v7.app.AlertDialog; import android.content.Intent; import android.content.pm.ActivityInfo; import android.content.pm.PackageManager; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.support.v7.widget.Toolbar; import android.util.Log; import android.view.KeyEvent; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.Surface; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.view.Window; import android.view.WindowManager; import java.io.IOException; import java.util.Collection; import java.util.Map; import piuk.blockchain.android.ui.base.BaseAuthActivity; import piuk.blockchain.android.R; /** * 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 final class CaptureActivity extends BaseAuthActivity implements SurfaceHolder.Callback { private static final String TAG = CaptureActivity.class.getSimpleName(); public static final String SCAN_RESULT = "SCAN_RESULT"; private CameraManager cameraManager; private CaptureActivityHandler handler; private Result savedResultToShow; private ViewfinderView viewfinderView; private boolean hasSurface; private IntentSource source; private Collection<BarcodeFormat> decodeFormats; private Map<DecodeHintType, ?> decodeHints; private String characterSet; private InactivityTimer inactivityTimer; private boolean hasFlashLight = false; private boolean flashStatus; ViewfinderView getViewfinderView() { return viewfinderView; } public Handler getHandler() { return handler; } CameraManager getCameraManager() { return cameraManager; } @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setRequestedOrientation(getCurrentOrientation()); Window window = getWindow(); window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); setContentView(R.layout.activity_scan); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar_general); setupToolbar(toolbar, R.string.scan_qr); getSupportActionBar().setDisplayHomeAsUpEnabled(true); getSupportActionBar().setHomeButtonEnabled(true); hasSurface = false; inactivityTimer = new InactivityTimer(this); hasFlashLight = getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH); } private int getCurrentOrientation() { int rotation = getWindowManager().getDefaultDisplay().getRotation(); switch (rotation) { case Surface.ROTATION_0: case Surface.ROTATION_270: return ActivityInfo.SCREEN_ORIENTATION_PORTRAIT; default: return ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT;//reverse-mounted cameras on devices like the Nexus 5X } } @Override public boolean onSupportNavigateUp() { onBackPressed(); return true; } @Override public void finish() { super.finish(); } @Override protected 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(getApplication()); viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view); viewfinderView.setCameraManager(cameraManager); handler = null; resetStatusView(); 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); } inactivityTimer.onResume(); Intent intent = getIntent(); source = IntentSource.NONE; decodeFormats = null; characterSet = null; if (intent != null) { String action = intent.getAction(); if (Intents.Scan.ACTION.equals(action)) { // Scan the formats the intent requested, and return the result to the calling activity. source = IntentSource.NATIVE_APP_INTENT; decodeFormats = DecodeFormatManager.parseDecodeFormats(intent); decodeHints = DecodeHintManager.parseDecodeHints(intent); if (intent.hasExtra(Intents.Scan.WIDTH) && intent.hasExtra(Intents.Scan.HEIGHT)) { int width = intent.getIntExtra(Intents.Scan.WIDTH, 0); int height = intent.getIntExtra(Intents.Scan.HEIGHT, 0); if (width > 0 && height > 0) { cameraManager.setManualFramingRect(width, height); } } } characterSet = intent.getStringExtra(Intents.Scan.CHARACTER_SET); } } @Override protected void onPause() { if (handler != null) { handler.quitSynchronously(); handler = null; } inactivityTimer.onPause(); cameraManager.closeDriver(); if (!hasSurface) { SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view); SurfaceHolder surfaceHolder = surfaceView.getHolder(); surfaceHolder.removeCallback(this); } // Close scanner when going to background finish(); super.onPause(); } @Override protected void onDestroy() { inactivityTimer.shutdown(); super.onDestroy(); } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { switch (keyCode) { case KeyEvent.KEYCODE_BACK: setResult(RESULT_CANCELED); finish(); break; 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); return true; case KeyEvent.KEYCODE_VOLUME_UP: cameraManager.setTorch(true); 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) { } /** * A valid barcode has been found, so give an indication of success and show the results. * * @param rawResult The contents of the barcode. * @param barcode A greyscale bitmap of the camera data which was decoded. */ public void handleDecode(Result rawResult, Bitmap barcode) { inactivityTimer.onActivity(); boolean fromLiveScan = barcode != null; if (fromLiveScan) { // Then not from history, so beep/vibrate and we have an image to draw on drawResultPoints(barcode, rawResult); } handleDecodeExternally(rawResult); } /** * 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 rawResult The decoded results which contains the points to draw. */ private 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(ContextCompat.getColor(this, R.color.primary_blue_accent)); 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); } } } } private static void drawLine(Canvas canvas, Paint paint, ResultPoint a, ResultPoint b) { canvas.drawLine(a.getX(), a.getY(), b.getX(), b.getY(), paint); } private void handleDecodeExternally(Result rawResult) { // Log.v(TAG,rawResult.toString()); Intent intent = new Intent(getIntent().getAction()); intent.putExtra(SCAN_RESULT, rawResult.toString()); setResult(RESULT_OK, intent); finish(); } 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(this, surfaceHolder); // Creating the handler starts the preview, which can also throw a RuntimeException. if (handler == null) { handler = new CaptureActivityHandler(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 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, R.id.decode_succeeded, savedResultToShow); handler.sendMessage(message); } savedResultToShow = null; } } private void displayFrameworkBugMessageAndExit() { AlertDialog.Builder builder = new AlertDialog.Builder(this, R.style.AlertDialogStyle); builder.setTitle(getString(R.string.app_name)); builder.setMessage("There was a camera error."); builder.setPositiveButton(android.R.string.ok, new FinishListener(this)); builder.setOnCancelListener(new FinishListener(this)); builder.show(); } private void resetStatusView() { viewfinderView.setVisibility(View.VISIBLE); } public void drawViewfinder() { viewfinderView.drawViewfinder(); } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.action_flash_light: try { toggleTorch(); } catch (Exception e) { } return true; default: return super.onOptionsItemSelected(item); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu items for use in the action bar if (hasFlashLight) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.menu_scan, menu); } return super.onCreateOptionsMenu(menu); } private void toggleTorch() { flashStatus = !flashStatus; cameraManager.setTorch(flashStatus); } }