Adding ability to consume barcodes in BarcodeCaptureAcitivity by adding interface too BarcodeGraphicTracker

Author: Adam Hurwitz

visionSamples/barcode-reader/app/src/main/java/com/google/android/gms/samples/vision/barcodereader/BarcodeCaptureActivity.java

@@ -57,7 +57,7 @@
  * 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 {
+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.
@@ -170,7 +170,7 @@ private void createCameraSource(boolean autoFocus, boolean useFlash) {
         // 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);
+        BarcodeTrackerFactory barcodeFactory = new BarcodeTrackerFactory(mGraphicOverlay, this);
         barcodeDetector.setProcessor(
                 new MultiProcessor.Builder<>(barcodeFactory).build());
 
@@ -428,4 +428,9 @@ public void onScaleEnd(ScaleGestureDetector detector) {
             mCameraSource.doZoom(detector.getScaleFactor());
         }
     }
+
+    @Override
+    public void onBarcodeDetected(Barcode barcode) {
+        //do something with barcode data returned
+    }
 }

visionSamples/barcode-reader/app/src/main/java/com/google/android/gms/samples/vision/barcodereader/BarcodeGraphicTracker.java

@@ -15,6 +15,9 @@
  */
 package com.google.android.gms.samples.vision.barcodereader;
 
+import android.content.Context;
+import android.support.annotation.UiThread;
+
 import com.google.android.gms.samples.vision.barcodereader.ui.camera.GraphicOverlay;
 import com.google.android.gms.vision.Detector;
 import com.google.android.gms.vision.Tracker;
@@ -26,13 +29,30 @@
  * to an overlay, update the graphics as the item changes, and remove the graphics when the item
  * goes away.
  */
-class BarcodeGraphicTracker extends Tracker<Barcode> {
+public class BarcodeGraphicTracker extends Tracker<Barcode> {
     private GraphicOverlay<BarcodeGraphic> mOverlay;
     private BarcodeGraphic mGraphic;
 
-    BarcodeGraphicTracker(GraphicOverlay<BarcodeGraphic> overlay, BarcodeGraphic graphic) {
-        mOverlay = overlay;
-        mGraphic = graphic;
+    private BarcodeUpdateListener mBarcodeUpdateListener;
+
+    /**
+     * Consume the item instance detected from an Activity or Fragment level by implementing the
+     * BarcodeUpdateListener interface method onBarcodeDetected.
+     */
+    public interface BarcodeUpdateListener {
+        @UiThread
+        void onBarcodeDetected(Barcode barcode);
+    }
+
+    BarcodeGraphicTracker(GraphicOverlay<BarcodeGraphic> mOverlay, BarcodeGraphic mGraphic,
+                          Context context) {
+        this.mOverlay = mOverlay;
+        this.mGraphic = mGraphic;
+        if (context instanceof BarcodeUpdateListener) {
+            this.mBarcodeUpdateListener = (BarcodeUpdateListener) context;
+        } else {
+            throw new RuntimeException("Hosting activity must implement BarcodeUpdateListener");
+        }
     }
 
     /**
@@ -41,6 +61,7 @@ class BarcodeGraphicTracker extends Tracker<Barcode> {
     @Override
     public void onNewItem(int id, Barcode item) {
         mGraphic.setId(id);
+        mBarcodeUpdateListener.onBarcodeDetected(item);
     }
 
     /**

visionSamples/barcode-reader/app/src/main/java/com/google/android/gms/samples/vision/barcodereader/BarcodeTrackerFactory.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.gms.samples.vision.barcodereader;
 
+import android.content.Context;
+
 import com.google.android.gms.samples.vision.barcodereader.ui.camera.GraphicOverlay;
 import com.google.android.gms.vision.MultiProcessor;
 import com.google.android.gms.vision.Tracker;
@@ -26,15 +28,18 @@
  */
 class BarcodeTrackerFactory implements MultiProcessor.Factory<Barcode> {
     private GraphicOverlay<BarcodeGraphic> mGraphicOverlay;
+    private Context mContext;
 
-    BarcodeTrackerFactory(GraphicOverlay<BarcodeGraphic> barcodeGraphicOverlay) {
-        mGraphicOverlay = barcodeGraphicOverlay;
+    public BarcodeTrackerFactory(GraphicOverlay<BarcodeGraphic> mGraphicOverlay,
+                                 Context mContext) {
+        this.mGraphicOverlay = mGraphicOverlay;
+        this.mContext = mContext;
     }
 
     @Override
     public Tracker<Barcode> create(Barcode barcode) {
         BarcodeGraphic graphic = new BarcodeGraphic(mGraphicOverlay);
-        return new BarcodeGraphicTracker(mGraphicOverlay, graphic);
+        return new BarcodeGraphicTracker(mGraphicOverlay, graphic, mContext);
     }
 
 }