Fix showing thw showcase I get

Author: amlcurran

library/src/main/java/com/github/amlcurran/showcaseview/ShowcaseView.java

@@ -209,7 +209,6 @@ private void updateBitmap() {
                 bitmapBuffer.recycle();
             }
             bitmapBuffer = Bitmap.createBitmap(getMeasuredWidth(), getMeasuredHeight(), Bitmap.Config.ARGB_8888);
-
         }
     }
 
@@ -337,10 +336,17 @@ public void onAnimationEnd() {
     @Override
     public void show() {
         isShowing = true;
+        if (canUpdateBitmap()) {
+            updateBitmap();
+        }
         mEventListener.onShowcaseViewShow(this);
         fadeInShowcase();
     }
 
+    private boolean canUpdateBitmap() {
+        return getMeasuredHeight() > 0 && getMeasuredWidth() > 0;
+    }
+
     private void fadeInShowcase() {
         animationFactory.fadeInView(
                 this, fadeInMillis,