This is a wrap for the latest version of this Github project. The wrapper is almost a direct implementation of BarcodeCaptureActivity.java
The B4A project uses the default layout of the original barcodereader github project (except for some additions that I have added).
It basically turns this code (the original BarcodeCaptureActivity.java)....
.....into this (with some additional code added)....
It is not started as an external activity - the wrapper takes care of it all and reports results directly to B4A while the scanner is active.
When the scanner is active:
1. Click on a highlighted barcode - it will raise an event in the B4A project with the content of the barcode (1D / 2D). It will also display the content of the barcode that was clicked in the "snackbar/toast" at the bottom of the view when the scanner is active
2. Every time a barcode is detected it will raise an event id the B4A project (it will include doubles - revise the B4A code to filter doubles)
3. Do a LongClick on the scanner while it is active to toggle the Torch/Flash
Take note of the B4A manifest file
Attached the following:
1. zipped b4a project
2. b4a library files
3. resource.zip - extract it and copy the resource folder and its contents to be on the same folder level as that of the /Files and /Objects folders of the b4a project
4. DemoRes.zip - extract it and copy the DemoRes folder and its contents to be on the same folder level as that of the /Files and /Objects folders of the b4a project
5. The java code (you need to add the libs folder that contains the required jar files in order to compile it)
Done with B4A V7.80 and with an Android 7.0 device (also working on a KitKat device)
Take it for a test drive - shout if in doubt or if something out of the ordinary happens.
The B4A project uses the default layout of the original barcodereader github project (except for some additions that I have added).
It basically turns this code (the original BarcodeCaptureActivity.java)....
B4X:
/*
* Copyright (C) The Android Open Source Project
*
* 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.google.android.gms.samples.vision.barcodereader;
import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.Snackbar;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.android.gms.common.api.CommonStatusCodes;
import com.google.android.gms.samples.vision.barcodereader.ui.camera.CameraSource;
import com.google.android.gms.samples.vision.barcodereader.ui.camera.CameraSourcePreview;
import com.google.android.gms.samples.vision.barcodereader.ui.camera.GraphicOverlay;
import com.google.android.gms.vision.MultiProcessor;
import com.google.android.gms.vision.barcode.Barcode;
import com.google.android.gms.vision.barcode.BarcodeDetector;
import java.io.IOException;
/**
* Activity for the multi-tracker app. This app detects barcodes and displays the value with the
* rear facing camera. During detection overlay graphics are drawn to indicate the position,
* size, and ID of each barcode.
*/
public final class BarcodeCaptureActivity extends AppCompatActivity implements BarcodeGraphicTracker.BarcodeUpdateListener {
private static final String TAG = "Barcode-reader";
// intent request code to handle updating play services if needed.
private static final int RC_HANDLE_GMS = 9001;
// permission request codes need to be < 256
private static final int RC_HANDLE_CAMERA_PERM = 2;
// constants used to pass extra data in the intent
public static final String AutoFocus = "AutoFocus";
public static final String UseFlash = "UseFlash";
public static final String BarcodeObject = "Barcode";
private CameraSource mCameraSource;
private CameraSourcePreview mPreview;
private GraphicOverlay<BarcodeGraphic> mGraphicOverlay;
// helper objects for detecting taps and pinches.
private ScaleGestureDetector scaleGestureDetector;
private GestureDetector gestureDetector;
/**
* Initializes the UI and creates the detector pipeline.
*/
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.barcode_capture);
mPreview = (CameraSourcePreview) findViewById(R.id.preview);
mGraphicOverlay = (GraphicOverlay<BarcodeGraphic>) findViewById(R.id.graphicOverlay);
// read parameters from the intent used to launch the activity.
boolean autoFocus = getIntent().getBooleanExtra(AutoFocus, false);
boolean useFlash = getIntent().getBooleanExtra(UseFlash, false);
// Check for the camera permission before accessing the camera. If the
// permission is not granted yet, request permission.
int rc = ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA);
if (rc == PackageManager.PERMISSION_GRANTED) {
createCameraSource(true, useFlash);
} else {
requestCameraPermission();
}
gestureDetector = new GestureDetector(this, new CaptureGestureListener());
scaleGestureDetector = new ScaleGestureDetector(this, new ScaleListener());
Snackbar.make(mGraphicOverlay, "Tap to capture. Pinch/Stretch to zoom",
Snackbar.LENGTH_LONG)
.show();
}
/**
* Handles the requesting of the camera permission. This includes
* showing a "Snackbar" message of why the permission is needed then
* sending the request.
*/
private void requestCameraPermission() {
Log.w(TAG, "Camera permission is not granted. Requesting permission");
final String[] permissions = new String[]{Manifest.permission.CAMERA};
if (!ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.CAMERA)) {
ActivityCompat.requestPermissions(this, permissions, RC_HANDLE_CAMERA_PERM);
return;
}
final Activity thisActivity = this;
View.OnClickListener listener = new View.OnClickListener() {
@Override
public void onClick(View view) {
ActivityCompat.requestPermissions(thisActivity, permissions,
RC_HANDLE_CAMERA_PERM);
}
};
findViewById(R.id.topLayout).setOnClickListener(listener);
Snackbar.make(mGraphicOverlay, R.string.permission_camera_rationale,
Snackbar.LENGTH_INDEFINITE)
.setAction(R.string.ok, listener)
.show();
}
@Override
public boolean onTouchEvent(MotionEvent e) {
boolean b = scaleGestureDetector.onTouchEvent(e);
boolean c = gestureDetector.onTouchEvent(e);
return b || c || super.onTouchEvent(e);
}
/**
* Creates and starts the camera. Note that this uses a higher resolution in comparison
* to other detection examples to enable the barcode detector to detect small barcodes
* at long distances.
*
* Suppressing InlinedApi since there is a check that the minimum version is met before using
* the constant.
*/
@SuppressLint("InlinedApi")
private void createCameraSource(boolean autoFocus, boolean useFlash) {
Context context = getApplicationContext();
// A barcode detector is created to track barcodes. An associated multi-processor instance
// is set to receive the barcode detection results, track the barcodes, and maintain
// graphics for each barcode on screen. The factory is used by the multi-processor to
// create a separate tracker instance for each barcode.
BarcodeDetector barcodeDetector = new BarcodeDetector.Builder(context).build();
BarcodeTrackerFactory barcodeFactory = new BarcodeTrackerFactory(mGraphicOverlay, this);
barcodeDetector.setProcessor(
new MultiProcessor.Builder<>(barcodeFactory).build());
if (!barcodeDetector.isOperational()) {
// Note: The first time that an app using the barcode or face API is installed on a
// device, GMS will download a native libraries to the device in order to do detection.
// Usually this completes before the app is run for the first time. But if that
// download has not yet completed, then the above call will not detect any barcodes
// and/or faces.
//
// isOperational() can be used to check if the required native libraries are currently
// available. The detectors will automatically become operational once the library
// downloads complete on device.
Log.w(TAG, "Detector dependencies are not yet available.");
// Check for low storage. If there is low storage, the native library will not be
// downloaded, so detection will not become operational.
IntentFilter lowstorageFilter = new IntentFilter(Intent.ACTION_DEVICE_STORAGE_LOW);
boolean hasLowStorage = registerReceiver(null, lowstorageFilter) != null;
if (hasLowStorage) {
Toast.makeText(this, R.string.low_storage_error, Toast.LENGTH_LONG).show();
Log.w(TAG, getString(R.string.low_storage_error));
}
}
// Creates and starts the camera. Note that this uses a higher resolution in comparison
// to other detection examples to enable the barcode detector to detect small barcodes
// at long distances.
CameraSource.Builder builder = new CameraSource.Builder(getApplicationContext(), barcodeDetector)
.setFacing(CameraSource.CAMERA_FACING_BACK)
.setRequestedPreviewSize(1600, 1024)
.setRequestedFps(15.0f);
// make sure that auto focus is an available option
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
builder = builder.setFocusMode(
autoFocus ? Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE : null);
}
mCameraSource = builder
.setFlashMode(useFlash ? Camera.Parameters.FLASH_MODE_TORCH : null)
.build();
}
/**
* Restarts the camera.
*/
@Override
protected void onResume() {
super.onResume();
startCameraSource();
}
/**
* Stops the camera.
*/
@Override
protected void onPause() {
super.onPause();
if (mPreview != null) {
mPreview.stop();
}
}
/**
* Releases the resources associated with the camera source, the associated detectors, and the
* rest of the processing pipeline.
*/
@Override
protected void onDestroy() {
super.onDestroy();
if (mPreview != null) {
mPreview.release();
}
}
/**
* Callback for the result from requesting permissions. This method
* is invoked for every call on {@link #requestPermissions(String[], int)}.
* <p>
* <strong>Note:</strong> It is possible that the permissions request interaction
* with the user is interrupted. In this case you will receive empty permissions
* and results arrays which should be treated as a cancellation.
* </p>
*
* @param requestCode The request code passed in {@link #requestPermissions(String[], int)}.
* @param permissions The requested permissions. Never null.
* @param grantResults The grant results for the corresponding permissions
* which is either {@link PackageManager#PERMISSION_GRANTED}
* or {@link PackageManager#PERMISSION_DENIED}. Never null.
* @see #requestPermissions(String[], int)
*/
@Override
public void onRequestPermissionsResult(int requestCode,
@NonNull String[] permissions,
@NonNull int[] grantResults) {
if (requestCode != RC_HANDLE_CAMERA_PERM) {
Log.d(TAG, "Got unexpected permission result: " + requestCode);
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
return;
}
if (grantResults.length != 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
Log.d(TAG, "Camera permission granted - initialize the camera source");
// we have permission, so create the camerasource
boolean autoFocus = getIntent().getBooleanExtra(AutoFocus,false);
boolean useFlash = getIntent().getBooleanExtra(UseFlash, false);
createCameraSource(autoFocus, useFlash);
return;
}
Log.e(TAG, "Permission not granted: results len = " + grantResults.length +
" Result code = " + (grantResults.length > 0 ? grantResults[0] : "(empty)"));
DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
finish();
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Multitracker sample")
.setMessage(R.string.no_camera_permission)
.setPositiveButton(R.string.ok, listener)
.show();
}
/**
* Starts or restarts the camera source, if it exists. If the camera source doesn't exist yet
* (e.g., because onResume was called before the camera source was created), this will be called
* again when the camera source is created.
*/
private void startCameraSource() throws SecurityException {
// check that the device has play services available.
int code = GoogleApiAvailability.getInstance().isGooglePlayServicesAvailable(
getApplicationContext());
if (code != ConnectionResult.SUCCESS) {
Dialog dlg =
GoogleApiAvailability.getInstance().getErrorDialog(this, code, RC_HANDLE_GMS);
dlg.show();
}
if (mCameraSource != null) {
try {
mPreview.start(mCameraSource, mGraphicOverlay);
} catch (IOException e) {
Log.e(TAG, "Unable to start camera source.", e);
mCameraSource.release();
mCameraSource = null;
}
}
}
/**
* onTap returns the tapped barcode result to the calling Activity.
*
* @param rawX - the raw position of the tap
* @param rawY - the raw position of the tap.
* @return true if the activity is ending.
*/
private boolean onTap(float rawX, float rawY) {
// Find tap point in preview frame coordinates.
int[] location = new int[2];
mGraphicOverlay.getLocationOnScreen(location);
float x = (rawX - location[0]) / mGraphicOverlay.getWidthScaleFactor();
float y = (rawY - location[1]) / mGraphicOverlay.getHeightScaleFactor();
// Find the barcode whose center is closest to the tapped point.
Barcode best = null;
float bestDistance = Float.MAX_VALUE;
for (BarcodeGraphic graphic : mGraphicOverlay.getGraphics()) {
Barcode barcode = graphic.getBarcode();
if (barcode.getBoundingBox().contains((int) x, (int) y)) {
// Exact hit, no need to keep looking.
best = barcode;
break;
}
float dx = x - barcode.getBoundingBox().centerX();
float dy = y - barcode.getBoundingBox().centerY();
float distance = (dx * dx) + (dy * dy); // actually squared distance
if (distance < bestDistance) {
best = barcode;
bestDistance = distance;
}
}
if (best != null) {
Intent data = new Intent();
data.putExtra(BarcodeObject, best);
setResult(CommonStatusCodes.SUCCESS, data);
finish();
return true;
}
return false;
}
private class CaptureGestureListener extends GestureDetector.SimpleOnGestureListener {
@Override
public boolean onSingleTapConfirmed(MotionEvent e) {
return onTap(e.getRawX(), e.getRawY()) || super.onSingleTapConfirmed(e);
}
}
private class ScaleListener implements ScaleGestureDetector.OnScaleGestureListener {
/**
* Responds to scaling events for a gesture in progress.
* Reported by pointer motion.
*
* @param detector The detector reporting the event - use this to
* retrieve extended info about event state.
* @return Whether or not the detector should consider this event
* as handled. If an event was not handled, the detector
* will continue to accumulate movement until an event is
* handled. This can be useful if an application, for example,
* only wants to update scaling factors if the change is
* greater than 0.01.
*/
@Override
public boolean onScale(ScaleGestureDetector detector) {
return false;
}
/**
* Responds to the beginning of a scaling gesture. Reported by
* new pointers going down.
*
* @param detector The detector reporting the event - use this to
* retrieve extended info about event state.
* @return Whether or not the detector should continue recognizing
* this gesture. For example, if a gesture is beginning
* with a focal point outside of a region where it makes
* sense, onScaleBegin() may return false to ignore the
* rest of the gesture.
*/
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
return true;
}
/**
* Responds to the end of a scale gesture. Reported by existing
* pointers going up.
* <p/>
* Once a scale has ended, {@link ScaleGestureDetector#getFocusX()}
* and {@link ScaleGestureDetector#getFocusY()} will return focal point
* of the pointers remaining on the screen.
*
* @param detector The detector reporting the event - use this to
* retrieve extended info about event state.
*/
@Override
public void onScaleEnd(ScaleGestureDetector detector) {
mCameraSource.doZoom(detector.getScaleFactor());
}
}
@Override
public void onBarcodeDetected(Barcode barcode) {
//do something with barcode data returned
}
}.....into this (with some additional code added)....
B4X:
/*
* Copyright (C) The Android Open Source Project
*
* 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 aaaaawrapper;
import anywheresoftware.b4a.AbsObjectWrapper;
import anywheresoftware.b4a.BA;
import anywheresoftware.b4a.BA.Author;
import anywheresoftware.b4a.BA.Hide;
import anywheresoftware.b4a.BA.Pixel;
import anywheresoftware.b4a.BA.ShortName;
import anywheresoftware.b4a.BA.Version;
import anywheresoftware.b4a.BALayout;
import anywheresoftware.b4a.BA.DependsOn;
import anywheresoftware.b4a.keywords.Common.DesignerCustomView;
import anywheresoftware.b4a.objects.LabelWrapper;
import anywheresoftware.b4a.objects.PanelWrapper;
import anywheresoftware.b4a.objects.ViewWrapper;
import anywheresoftware.b4a.BA.ActivityObject;
import anywheresoftware.b4a.BA.Events;
import anywheresoftware.b4a.IOnActivityResult;
import anywheresoftware.b4a.BA.Permissions;
import android.content.Intent;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.View;
import android.widget.CompoundButton;
import android.widget.TextView;
import android.graphics.Color;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import com.google.android.gms.common.api.CommonStatusCodes;
import com.google.android.gms.samples.vision.barcodereader.R;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.android.gms.common.api.CommonStatusCodes;
import com.google.android.gms.samples.vision.barcodereader.ui.camera.CameraSource;
import com.google.android.gms.samples.vision.barcodereader.ui.camera.CameraSourcePreview;
import com.google.android.gms.samples.vision.barcodereader.ui.camera.GraphicOverlay;
import com.google.android.gms.vision.MultiProcessor;
import com.google.android.gms.vision.barcode.Barcode;
import com.google.android.gms.vision.barcode.BarcodeDetector;
import com.google.android.gms.samples.vision.barcodereader.BarcodeGraphicTracker;
import com.google.android.gms.samples.vision.barcodereader.BarcodeGraphic;
import com.google.android.gms.samples.vision.barcodereader.BarcodeTrackerFactory;
import com.google.android.gms.vision.Tracker;
import com.google.android.gms.vision.barcode.Barcode;
import android.view.GestureDetector;
import android.view.ScaleGestureDetector;
import android.view.MotionEvent;
import android.Manifest;
import android.content.pm.PackageManager;
import android.support.design.widget.Snackbar;
import android.content.Context;
import android.content.IntentFilter;
import android.widget.Toast;
import android.os.Build;
import android.os.Bundle;
import android.hardware.Camera;
import android.app.AlertDialog;
import android.app.Dialog;
import java.io.IOException;
import android.view.View.OnLongClickListener;
@ActivityObject
@ShortName("VisionBarcodeScanner")
@Events(values={"touch_result(data As String)", "detected_result(data As String)"})
//@Author("Github: Clayton Wilkinson, Wrapped by: Johan Schoeman")
@Version(1.00f)
@DependsOn(values={"com.android.support:support-v4", "com.android.support:appcompat-v7", "com.google.android.gms:play-services-vision", "com.android.support:design"})
@Permissions(values={"android.permission.CAMERA","android.permission.WRITE_EXTERNAL_STORAGE","android.hardware.camera","android.hardware.camera.autofocus","android.permission.VIBRATE","android.permission.FLASHLIGHT"})
public class aaaaaWrapper extends AppCompatActivity implements BarcodeGraphicTracker.BarcodeUpdateListener { //implements View.OnClickListener {
//public class androidVisionMasterWrapper implements View.OnClickListener {
@Hide
public BA ba;
@Hide
public String eventName;
private static final String TAG = "Barcode-reader";
// intent request code to handle updating play services if needed.
private static final int RC_HANDLE_GMS = 9001;
// permission request codes need to be < 256
private static final int RC_HANDLE_CAMERA_PERM = 2;
// constants used to pass extra data in the intent
public static final String AutoFocus = "AutoFocus";
public static final String UseFlash = "UseFlash";
public static final String BarcodeObject = "Barcode";
private CameraSource mCameraSource;
private CameraSourcePreview mPreview;
private GraphicOverlay<BarcodeGraphic> mGraphicOverlay;
private boolean flashIsOn = false;
public void Initialize(BA paramBA, String paramString) {
eventName = paramString.toLowerCase(BA.cul);
ba = paramBA;
String str = paramString.toLowerCase(BA.cul);
}
public void BeginScan() {
ba.activity.setContentView(R.layout.barcode_capture);
mPreview = (CameraSourcePreview) ba.activity.findViewById(R.id.preview);
mGraphicOverlay = (GraphicOverlay<BarcodeGraphic>) ba.activity.findViewById(R.id.graphicOverlay);
mPreview.setOnTouchListener(touchListener);
mPreview.setOnLongClickListener(new OnLongClickListener() {
public boolean onLongClick(View arg0) {
if (flashIsOn == false) {
mCameraSource.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
flashIsOn = true;
Snackbar.make(mGraphicOverlay, "Flash/Torch turned on",
Snackbar.LENGTH_LONG)
.show();
} else {
mCameraSource.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
flashIsOn = false;
Snackbar.make(mGraphicOverlay, "Flash/Torch turned off",
Snackbar.LENGTH_LONG)
.show();
}
return true; // <- set to true
}
});
// read parameters from the intent used to launch the activity.
boolean autoFocus = true;
boolean useFlash = false;
createCameraSource(true, useFlash);
Snackbar.make(mGraphicOverlay, "1. Touch a highlighted barcode to get its value \n2. LongClick the scanner to toggle the Flash",
Snackbar.LENGTH_LONG)
.show();
startCameraSource();
}
public void StopScan() {
if (mPreview != null) {
mPreview.release();
}
}
private int raised = 0;
View.OnTouchListener touchListener = new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getActionMasked() == MotionEvent.ACTION_UP) {
onTap(event.getRawX(), event.getRawY());
}
return false;
}
};
/**
* Creates and starts the camera. Note that this uses a higher resolution in comparison
* to other detection examples to enable the barcode detector to detect small barcodes
* at long distances.
*
* Suppressing InlinedApi since there is a check that the minimum version is met before using
* the constant.
*/
private void createCameraSource(boolean autoFocus, boolean useFlash) {
Context context = ba.applicationContext;
// A barcode detector is created to track barcodes. An associated multi-processor instance
// is set to receive the barcode detection results, track the barcodes, and maintain
// graphics for each barcode on screen. The factory is used by the multi-processor to
// create a separate tracker instance for each barcode.
BarcodeDetector barcodeDetector = new BarcodeDetector.Builder(context).build();
BarcodeTrackerFactory barcodeFactory = new BarcodeTrackerFactory(mGraphicOverlay, this);
barcodeDetector.setProcessor(
new MultiProcessor.Builder<>(barcodeFactory).build());
if (!barcodeDetector.isOperational()) {
// Note: The first time that an app using the barcode or face API is installed on a
// device, GMS will download a native libraries to the device in order to do detection.
// Usually this completes before the app is run for the first time. But if that
// download has not yet completed, then the above call will not detect any barcodes
// and/or faces.
//
// isOperational() can be used to check if the required native libraries are currently
// available. The detectors will automatically become operational once the library
// downloads complete on device.
BA.Log("Detector dependencies are not yet available.");
// Check for low storage. If there is low storage, the native library will not be
// downloaded, so detection will not become operational.
IntentFilter lowstorageFilter = new IntentFilter(Intent.ACTION_DEVICE_STORAGE_LOW);
boolean hasLowStorage = registerReceiver(null, lowstorageFilter) != null;
if (hasLowStorage) {
Toast.makeText(ba.applicationContext, R.string.low_storage_error, Toast.LENGTH_LONG).show();
BA.Log("" + getString(R.string.low_storage_error));
}
}
// Creates and starts the camera. Note that this uses a higher resolution in comparison
// to other detection examples to enable the barcode detector to detect small barcodes
// at long distances.
CameraSource.Builder builder = new CameraSource.Builder(ba.applicationContext, barcodeDetector)
.setFacing(CameraSource.CAMERA_FACING_BACK)
.setRequestedPreviewSize(1600, 1024)
.setRequestedFps(15.0f);
// make sure that auto focus is an available option
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
builder = builder.setFocusMode(
autoFocus ? Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE : null);
}
mCameraSource = builder
.setFlashMode(useFlash ? Camera.Parameters.FLASH_MODE_TORCH : null)
.build();
}
/**
* Starts or restarts the camera source, if it exists. If the camera source doesn't exist yet
* (e.g., because onResume was called before the camera source was created), this will be called
* again when the camera source is created.
*/
private void startCameraSource() throws SecurityException {
if (mCameraSource != null) {
try {
mPreview.start(mCameraSource, mGraphicOverlay);
} catch (IOException e) {
BA.Log("Unable to start camera source. " + e);
mCameraSource.release();
mCameraSource = null;
}
}
}
String mybarcode = "";
@Override
public void onBarcodeDetected(Barcode barcode) {
mybarcode = barcode.rawValue;
if (ba.subExists(eventName + "_detected_result")) {
ba.raiseEventFromDifferentThread(ba.applicationContext, null, 0, eventName + "_detected_result", true, new Object[] {barcode.rawValue});
}
}
/**
* onTap returns the tapped barcode result to the calling Activity.
*
* @param rawX - the raw position of the tap
* @param rawY - the raw position of the tap.
* @return true if the activity is ending.
*/
private boolean onTap(float rawX, float rawY) {
// Find tap point in preview frame coordinates.
int[] location = new int[2];
mGraphicOverlay.getLocationOnScreen(location);
float x = (rawX - location[0]) / mGraphicOverlay.getWidthScaleFactor();
float y = (rawY - location[1]) / mGraphicOverlay.getHeightScaleFactor();
// Find the barcode whose center is closest to the tapped point.
Barcode best = null;
float bestDistance = Float.MAX_VALUE;
for (BarcodeGraphic graphic : mGraphicOverlay.getGraphics()) {
Barcode barcode = graphic.getBarcode();
if (barcode.getBoundingBox().contains((int) x, (int) y)) {
// Exact hit, no need to keep looking.
best = barcode;
break;
}
float dx = x - barcode.getBoundingBox().centerX();
float dy = y - barcode.getBoundingBox().centerY();
float distance = (dx * dx) + (dy * dy); // actually squared distance
if (distance < bestDistance) {
best = barcode;
bestDistance = distance;
}
}
if (best != null) {
Snackbar.make(mGraphicOverlay, best.rawValue,
Snackbar.LENGTH_SHORT)
.show();
if (ba.subExists(eventName + "_touch_result")) {
ba.raiseEventFromDifferentThread(ba.applicationContext, null, 0, eventName + "_touch_result", true, new Object[] {best.rawValue});
}
//}
finish();
return true;
}
return false;
}
}It is not started as an external activity - the wrapper takes care of it all and reports results directly to B4A while the scanner is active.
When the scanner is active:
1. Click on a highlighted barcode - it will raise an event in the B4A project with the content of the barcode (1D / 2D). It will also display the content of the barcode that was clicked in the "snackbar/toast" at the bottom of the view when the scanner is active
2. Every time a barcode is detected it will raise an event id the B4A project (it will include doubles - revise the B4A code to filter doubles)
3. Do a LongClick on the scanner while it is active to toggle the Torch/Flash
Take note of the B4A manifest file
B4X:
'This code will be applied to the manifest file during compilation.
'You do not need to modify it in most cases.
'See this link for for more information: https://www.b4x.com/forum/showthread.php?p=78136
AddManifestText(
<uses-sdk android:minSdkVersion="5" android:targetSdkVersion="22"/>
<supports-screens android:largeScreens="true"
android:normalScreens="true"
android:smallScreens="true"
android:anyDensity="true"/>)
SetApplicationAttribute(android:icon, "@drawable/icon")
SetApplicationAttribute(android:label, "$LABEL$")
SetApplicationAttribute(android:theme, "@style/MyAppTheme")
AddApplicationText(<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
<meta-data
android:name="com.google.android.gms.vision.DEPENDENCIES"
android:value="barcode" />)
' <activity android:name="com.google.android.gms.samples.vision.barcodereader.BarcodeCaptureActivity"
' android:screenOrientation="portrait" android:configChanges="orientation|keyboardHidden">
' </activity>)
AddPermission(android.permission.CAMERA) ' Required to be able to access the camera device.
AddPermission(android.permission.GET_TASKS)
AddPermission("android.hardware.camera")
AddPermission("android.permission.FLASHLIGHT")Attached the following:
1. zipped b4a project
2. b4a library files
3. resource.zip - extract it and copy the resource folder and its contents to be on the same folder level as that of the /Files and /Objects folders of the b4a project
4. DemoRes.zip - extract it and copy the DemoRes folder and its contents to be on the same folder level as that of the /Files and /Objects folders of the b4a project
5. The java code (you need to add the libs folder that contains the required jar files in order to compile it)
Done with B4A V7.80 and with an Android 7.0 device (also working on a KitKat device)
Take it for a test drive - shout if in doubt or if something out of the ordinary happens.
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