Java tutorial
package com.crownpay.wallet.ui; /* * Copyright 2012-2014 the original author or authors. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ import static android.Manifest.permission.CAMERA; import android.app.Activity; import android.content.Context; import android.content.Intent; import static android.content.pm.PackageManager.PERMISSION_GRANTED; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.hardware.Camera; import android.hardware.Camera.PreviewCallback; import android.os.Build; import android.os.Bundle; import android.os.Handler; import android.os.HandlerThread; import android.os.Process; import android.os.Vibrator; import android.support.annotation.NonNull; import android.support.v4.app.ActivityCompat; import android.support.v4.app.FragmentActivity; import android.support.v4.content.ContextCompat; import android.view.KeyEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.widget.Toast; import com.crownpay.wallet.Constants; import com.crownpay.wallet.R; import com.crownpay.wallet.camera.CameraManager; import com.google.zxing.BinaryBitmap; import com.google.zxing.DecodeHintType; import com.google.zxing.PlanarYUVLuminanceSource; import com.google.zxing.ReaderException; import com.google.zxing.Result; import com.google.zxing.ResultPoint; import com.google.zxing.ResultPointCallback; import com.google.zxing.common.HybridBinarizer; import com.google.zxing.qrcode.QRCodeReader; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.util.EnumMap; import java.util.Map; /** * @author Andreas Schildbach * @author John L. Jegutanis */ public final class ScanActivity extends FragmentActivity implements SurfaceHolder.Callback { public static final String INTENT_EXTRA_RESULT = "result"; private static final long VIBRATE_DURATION = 50L; private static final long AUTO_FOCUS_INTERVAL_MS = 2500L; private final CameraManager cameraManager = new CameraManager(); private ScannerView scannerView; private SurfaceHolder surfaceHolder; private Vibrator vibrator; private HandlerThread cameraThread; private Handler cameraHandler; private boolean isSurfaceCreated = false; private static final int DIALOG_CAMERA_PROBLEM = 0; private static boolean DISABLE_CONTINUOUS_AUTOFOCUS = Build.MODEL.equals("GT-I9100") // Galaxy S2 || Build.MODEL.equals("SGH-T989") // Galaxy S2 || Build.MODEL.equals("SGH-T989D") // Galaxy S2 X || Build.MODEL.equals("SAMSUNG-SGH-I727") // Galaxy S2 Skyrocket || Build.MODEL.equals("GT-I9300") // Galaxy S3 || Build.MODEL.equals("GT-N7000"); // Galaxy Note private static final Logger log = LoggerFactory.getLogger(ScanActivity.class); @Override public void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE); setContentView(R.layout.scan_activity); scannerView = (ScannerView) findViewById(R.id.scan_activity_mask); } @Override protected void onResume() { super.onResume(); cameraThread = new HandlerThread("cameraThread", Process.THREAD_PRIORITY_BACKGROUND); cameraThread.start(); cameraHandler = new Handler(cameraThread.getLooper()); final SurfaceView surfaceView = (SurfaceView) findViewById(R.id.scan_activity_preview); surfaceHolder = surfaceView.getHolder(); surfaceHolder.addCallback(this); surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); if (!hasCameraPermission()) { askCameraPermission(); } else { openCamera(); } } @Override protected void onPause() { cameraHandler.post(closeRunnable); surfaceHolder.removeCallback(this); super.onPause(); } private void askCameraPermission() { if (!hasCameraPermission()) { ActivityCompat.requestPermissions(this, new String[] { CAMERA }, Constants.PERMISSIONS_REQUEST_CAMERA); } } private boolean hasCameraPermission() { return ContextCompat.checkSelfPermission(this, CAMERA) == PERMISSION_GRANTED; } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { if (requestCode == Constants.PERMISSIONS_REQUEST_CAMERA) { for (int i = 0; i < permissions.length; i++) { if (permissions[i].equals(CAMERA) && grantResults[i] == PERMISSION_GRANTED) { break; } } if (!hasCameraPermission()) showErrorToast(); } } @Override public void surfaceCreated(final SurfaceHolder holder) { isSurfaceCreated = true; openCamera(); } private void openCamera() { if (isSurfaceCreated && hasCameraPermission()) { cameraHandler.post(openRunnable); } } @Override public void surfaceDestroyed(final SurfaceHolder holder) { } @Override public void surfaceChanged(final SurfaceHolder holder, final int format, final int width, final int height) { } @Override public void onBackPressed() { setResult(RESULT_CANCELED); finish(); } @Override public boolean onKeyDown(final int keyCode, final KeyEvent event) { switch (keyCode) { case KeyEvent.KEYCODE_FOCUS: case KeyEvent.KEYCODE_CAMERA: // don't launch camera app return true; case KeyEvent.KEYCODE_VOLUME_DOWN: case KeyEvent.KEYCODE_VOLUME_UP: cameraHandler.post(new Runnable() { @Override public void run() { cameraManager.setTorch(keyCode == KeyEvent.KEYCODE_VOLUME_UP); } }); return true; } return super.onKeyDown(keyCode, event); } public void handleResult(final Result scanResult, final Bitmap thumbnailImage, final float thumbnailScaleFactor) { vibrator.vibrate(VIBRATE_DURATION); // superimpose dots to highlight the key features of the qr code final ResultPoint[] points = scanResult.getResultPoints(); if (points != null && points.length > 0) { final Paint paint = new Paint(); paint.setColor(getResources().getColor(R.color.scan_result_dots)); paint.setStrokeWidth(10.0f); final Canvas canvas = new Canvas(thumbnailImage); canvas.scale(thumbnailScaleFactor, thumbnailScaleFactor); for (final ResultPoint point : points) canvas.drawPoint(point.getX(), point.getY(), paint); } scannerView.drawResultBitmap(thumbnailImage); final Intent result = new Intent(); result.putExtra(INTENT_EXTRA_RESULT, scanResult.getText()); setResult(RESULT_OK, result); // delayed finish new Handler().post(new Runnable() { @Override public void run() { finish(); } }); } private final Runnable openRunnable = new Runnable() { @Override public void run() { try { final Camera camera = cameraManager.open(surfaceHolder, !DISABLE_CONTINUOUS_AUTOFOCUS); final Rect framingRect = cameraManager.getFrame(); final Rect framingRectInPreview = cameraManager.getFramePreview(); runOnUiThread(new Runnable() { @Override public void run() { scannerView.setFraming(framingRect, framingRectInPreview); } }); final String focusMode = camera.getParameters().getFocusMode(); final boolean nonContinuousAutoFocus = Camera.Parameters.FOCUS_MODE_AUTO.equals(focusMode) || Camera.Parameters.FOCUS_MODE_MACRO.equals(focusMode); if (nonContinuousAutoFocus) cameraHandler.post(new AutoFocusRunnable(camera)); cameraHandler.post(fetchAndDecodeRunnable); } catch (final IOException x) { log.info("problem opening camera", x); showErrorToast(); } catch (final RuntimeException x) { log.info("problem opening camera", x); showErrorToast(); } } }; private void showErrorToast() { runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(ScanActivity.this, R.string.error_camera, Toast.LENGTH_LONG).show(); finish(); } }); } private final Runnable closeRunnable = new Runnable() { @Override public void run() { cameraManager.close(); // cancel background thread cameraHandler.removeCallbacksAndMessages(null); cameraThread.quit(); } }; private final class AutoFocusRunnable implements Runnable { private final Camera camera; public AutoFocusRunnable(final Camera camera) { this.camera = camera; } @Override public void run() { camera.autoFocus(new Camera.AutoFocusCallback() { @Override public void onAutoFocus(final boolean success, final Camera camera) { // schedule again cameraHandler.postDelayed(AutoFocusRunnable.this, AUTO_FOCUS_INTERVAL_MS); } }); } } private final Runnable fetchAndDecodeRunnable = new Runnable() { private final QRCodeReader reader = new QRCodeReader(); private final Map<DecodeHintType, Object> hints = new EnumMap<DecodeHintType, Object>(DecodeHintType.class); @Override public void run() { cameraManager.requestPreviewFrame(new PreviewCallback() { @Override public void onPreviewFrame(final byte[] data, final Camera camera) { decode(data); } }); } private void decode(final byte[] data) { final PlanarYUVLuminanceSource source = cameraManager.buildLuminanceSource(data); final BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); try { hints.put(DecodeHintType.NEED_RESULT_POINT_CALLBACK, new ResultPointCallback() { @Override public void foundPossibleResultPoint(final ResultPoint dot) { runOnUiThread(new Runnable() { @Override public void run() { scannerView.addDot(dot); } }); } }); final Result scanResult = reader.decode(bitmap, hints); final int thumbnailWidth = source.getThumbnailWidth(); final int thumbnailHeight = source.getThumbnailHeight(); final float thumbnailScaleFactor = (float) thumbnailWidth / source.getWidth(); final Bitmap thumbnailImage = Bitmap.createBitmap(thumbnailWidth, thumbnailHeight, Bitmap.Config.ARGB_8888); thumbnailImage.setPixels(source.renderThumbnail(), 0, thumbnailWidth, 0, 0, thumbnailWidth, thumbnailHeight); runOnUiThread(new Runnable() { @Override public void run() { handleResult(scanResult, thumbnailImage, thumbnailScaleFactor); } }); } catch (final ReaderException x) { // retry cameraHandler.post(fetchAndDecodeRunnable); } finally { reader.reset(); } } }; }