[android-developers] Re: getRotationMatrixFromVector() broken on Note 3

I encountered the same problem with a Samsung S4.

On Wednesday, October 2, 2013 8:41:01 AM UTC-5, String wrote:

I've been getting error reports from users of the Note 3 that boil down to the following:

java.lang.IllegalArgumentException: R array length must be 3 or 4

at android.hardware.SensorManager.getRotationMatrixFromVector(SensorManager.java:1336)

This function, getRotationMatrixFromVector(), is documented as a "Helper function to convert a rotation vector to a rotation matrix. Given a rotation vector (presumably from a ROTATION_VECTOR sensor)". My typical call to this function looks like this:

SensorManager.getRotationMatrixFromVector(R, rotationVector);

Where the rotationVector comes from the hardware accelerometer and gyroscope, and (despite the error message about R) it's with this parameter where the problem lies. It's directly passed from android.hardware.SensorEventListener.onSensorChanged(SensorEvent event) for a Sensor.TYPE_ROTATION_VECTOR event. The event parameter there has a values property that is passed as the rotationVector in the previous call. And according to the docs at
http://developer.android.com/reference/android/hardware/SensorEvent.html#values, this array can legitimately have up to 5 elements - moreover, in Android 4.3, it should have all 5. However, passing an array of length 5 causes the Note 3 to crash on the aforementioned IllegalArgumentException; it seems to expect 4 elements at most.

So, here's the summary: Android 4.3 passes an array with 5 elements to this hardware event, and the Note 3 throws an exception when passed that same array to the system-defined helper function for that event. This behavior does not happen on the other 4.3 devices I have at hand (Galaxy Nexus and Nexus 7); it appears to be a basic flaw in the Samsung implementation of 4.3.

And I know, this all looks like minutiae of a hyper-specific issue - but believe me, it's likely to be encountered by any app using the device's motion sensors. A Google search for getRotationMatrixFromVector returns 51,400 results.

Any comment from Samsung on this would be most welcome, if unlikely.

String

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