Merge pull request #135 from googlesamples/tap-fix

Return tapped (or closest) barcode result to calling Activity.

Author: pchx

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

@@ -325,41 +325,51 @@ private void startCameraSource() throws SecurityException {
     }
 
     /**
-     * onTap is called to capture the oldest barcode currently detected and
-     * return it to the caller.
+     * 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) {
-
-        //TODO: use the tap position to select the barcode.
-        BarcodeGraphic graphic = mGraphicOverlay.getFirstGraphic();
-        Barcode barcode = null;
-        if (graphic != null) {
-            barcode = graphic.getBarcode();
-            if (barcode != null) {
-                Intent data = new Intent();
-                data.putExtra(BarcodeObject, barcode);
-                setResult(CommonStatusCodes.SUCCESS, data);
-                finish();
+        // 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;
             }
-            else {
-                Log.d(TAG, "barcode data is null");
+            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;
             }
         }
-        else {
-            Log.d(TAG,"no barcode detected");
+
+        if (best != null) {
+            Intent data = new Intent();
+            data.putExtra(BarcodeObject, best);
+            setResult(CommonStatusCodes.SUCCESS, data);
+            finish();
+            return true;
         }
-        return barcode != null;
+        return false;
     }
 
     private class CaptureGestureListener extends GestureDetector.SimpleOnGestureListener {
-
         @Override
         public boolean onSingleTapConfirmed(MotionEvent e) {
-
             return onTap(e.getRawX(), e.getRawY()) || super.onSingleTapConfirmed(e);
         }
     }

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

@@ -23,7 +23,9 @@
 import com.google.android.gms.vision.CameraSource;
 
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
+import java.util.Vector;
 
 /**
  * A view which renders a series of custom graphics to be overlayed on top of an associated preview
@@ -51,7 +53,6 @@ public class GraphicOverlay<T extends GraphicOverlay.Graphic> extends View {
     private float mHeightScaleFactor = 1.0f;
     private int mFacing = CameraSource.CAMERA_FACING_BACK;
     private Set<T> mGraphics = new HashSet<>();
-    private T mFirstGraphic;
 
     /**
      * Base class for a custom graphics object to be rendered within the graphic overlay.  Subclass
@@ -129,7 +130,6 @@ public GraphicOverlay(Context context, AttributeSet attrs) {
     public void clear() {
         synchronized (mLock) {
             mGraphics.clear();
-            mFirstGraphic = null;
         }
         postInvalidate();
     }
@@ -140,9 +140,6 @@ public void clear() {
     public void add(T graphic) {
         synchronized (mLock) {
             mGraphics.add(graphic);
-            if (mFirstGraphic == null) {
-                mFirstGraphic = graphic;
-            }
         }
         postInvalidate();
     }
@@ -153,24 +150,34 @@ public void add(T graphic) {
     public void remove(T graphic) {
         synchronized (mLock) {
             mGraphics.remove(graphic);
-            if (mFirstGraphic != null && mFirstGraphic.equals(graphic)) {
-                mFirstGraphic = null;
-            }
         }
         postInvalidate();
     }
 
     /**
-     * Returns the first (oldest) graphic added.  This is used
-     * to get the barcode that was detected first.
-     * @return graphic containing the barcode, or null if no barcodes are detected.
+     * Returns a copy (as a list) of the set of all active graphics.
+     * @return list of all active graphics.
      */
-    public T getFirstGraphic() {
+    public List<T> getGraphics() {
         synchronized (mLock) {
-            return mFirstGraphic;
+            return new Vector(mGraphics);
         }
     }
 
+    /**
+     * Returns the horizontal scale factor.
+     */
+    public float getWidthScaleFactor() {
+        return mWidthScaleFactor;
+    }
+
+    /**
+     * Returns the vertical scale factor.
+     */
+    public float getHeightScaleFactor() {
+        return mHeightScaleFactor;
+    }
+
     /**
      * Sets the camera attributes for size and facing direction, which informs how to transform
      * image coordinates later.