Let visibility of "laser scanner" be set (#503)

* Add laser visibility attribute

* Add laser visibility attribute usage to sample project

- set to true to stick with the current behavior
- included for didactic reasons

* Add laser visibility attribute to ViewfinderView and set it accordingly

* Draw "laser scanner" only if wanted

* Let laser visibility be changed programmatically

* Add sample code to show how laser visibility can be changed programmatically

Author: Andre Ippisch

sample/src/main/java/example/zxing/CustomScannerActivity.java

@@ -48,6 +48,7 @@ protected void onCreate(Bundle savedInstanceState) {
         capture.decode();
 
         changeMaskColor(null);
+        changeLaserVisibility(true);
     }
 
     @Override
@@ -102,6 +103,10 @@ public void changeMaskColor(View view) {
         viewfinderView.setMaskColor(color);
     }
 
+    public void changeLaserVisibility(boolean visible) {
+        viewfinderView.setLaserVisibility(visible);
+    }
+
     @Override
     public void onTorchOn() {
         switchFlashlightButton.setText(R.string.turn_off_flashlight);

sample/src/main/res/layout/custom_barcode_scanner.xml

@@ -17,6 +17,7 @@
         app:zxing_possible_result_points="@color/zxing_custom_possible_result_points"
         app:zxing_result_view="@color/zxing_custom_result_view"
         app:zxing_viewfinder_laser="@color/zxing_custom_viewfinder_laser"
+        app:zxing_viewfinder_laser_visibility="true"
         app:zxing_viewfinder_mask="@color/zxing_custom_viewfinder_mask"/>
 
     <TextView

zxing-android-embedded/res/values/zxing_attrs.xml

@@ -21,6 +21,7 @@
     <attr name="zxing_result_view" format="color"/>
     <attr name="zxing_viewfinder_laser" format="color"/>
     <attr name="zxing_viewfinder_mask" format="color"/>
+    <attr name="zxing_viewfinder_laser_visibility" format="boolean"/>
   </declare-styleable>
 
 </resources>

zxing-android-embedded/src/com/journeyapps/barcodescanner/ViewfinderView.java

@@ -54,6 +54,7 @@ public class ViewfinderView extends View {
     protected final int resultColor;
     protected final int laserColor;
     protected final int resultPointColor;
+    protected boolean laserVisibility;
     protected int scannerAlpha;
     protected List<ResultPoint> possibleResultPoints;
     protected List<ResultPoint> lastPossibleResultPoints;
@@ -84,6 +85,8 @@ public ViewfinderView(Context context, AttributeSet attrs) {
                 resources.getColor(R.color.zxing_viewfinder_laser));
         this.resultPointColor = attributes.getColor(R.styleable.zxing_finder_zxing_possible_result_points,
                 resources.getColor(R.color.zxing_possible_result_points));
+        this.laserVisibility = attributes.getBoolean(R.styleable.zxing_finder_zxing_viewfinder_laser_visibility,
+                true);
 
         attributes.recycle();
 
@@ -160,13 +163,16 @@ public void onDraw(Canvas canvas) {
             paint.setAlpha(CURRENT_POINT_OPACITY);
             canvas.drawBitmap(resultBitmap, null, frame, paint);
         } else {
+            // If wanted, draw a red "laser scanner" line through the middle to show decoding is active
+            if (laserVisibility) {
+                paint.setColor(laserColor);
 
-            // Draw a red "laser scanner" line through the middle to show decoding is active
-            paint.setColor(laserColor);
-            paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
-            scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
-            final int middle = frame.height() / 2 + frame.top;
-            canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);
+                paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
+                scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
+
+                final int middle = frame.height() / 2 + frame.top;
+                canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);
+            }
 
             final float scaleX = this.getWidth() / (float) previewSize.width;
             final float scaleY = this.getHeight() / (float) previewSize.height;
@@ -247,4 +253,8 @@ public void addPossibleResultPoint(ResultPoint point) {
     public void setMaskColor(int maskColor) {
         this.maskColor = maskColor;
     }
+
+    public void setLaserVisibility(boolean visible) {
+        this.laserVisibility = visible;
+    }
 }