Doc: update Accelbubble example

The app could not recover from receiving a NaN value from
the Accelerometer, so NaN values are ignored.

Change-Id: Ia33d800f7fe080e07dcf327c26b3772e994793bf
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>

2 files changed, 6 insertions, 0 deletions

diff --git a/doc/examples/accelbubble/main.qml b/doc/examples/accelbubble/main.qml
index 80c961f78b..0f3d198941 100644
--- a/doc/examples/accelbubble/main.qml
+++ b/doc/examples/accelbubble/main.qml
@@ -79,6 +79,9 @@ ApplicationWindow {
             var newX = (bubble.x + calcRoll(accel.reading.x, accel.reading.y, accel.reading.z) * 0.1)
             var newY = (bubble.y - calcPitch(accel.reading.x, accel.reading.y, accel.reading.z) * 0.1)
 
+            if (isNaN(newX) || isNaN(newY))
+                return;
+
             if (newX < 0)
                 newX = 0
 
diff --git a/doc/src/qtquick/creator-mobile-app-tutorial.qdoc b/doc/src/qtquick/creator-mobile-app-tutorial.qdoc
index 483f9cd665..09713b4d83 100644
--- a/doc/src/qtquick/creator-mobile-app-tutorial.qdoc
+++ b/doc/src/qtquick/creator-mobile-app-tutorial.qdoc
@@ -196,6 +196,9 @@
             \skipto onReadingChanged
             \printuntil }
 
+            We want to ensure that the position of the bubble is always within
+            the bounds of the screen. If the Accelerometer returns not a number
+            (NaN), the value is ignored and the bubble position is not updated.
         \li Add SmoothedAnimation behavior on the \a x and \a y properties of
             the bubble to make its movement look smoother.