Android TextureView and hardware acceleration

I am trying to implement the example shown on this page . I tried three different devices running Android 4 and above, and in all cases I get a black screen with this warning:

01-27 20:01:22.683: W/TextureView(4728): A TextureView or a subclass can only be used with hardware acceleration enabled.

I turned on hardware acceleration in the application manifest:

<application
    android:hardwareAccelerated="true"
    [etc...]

But the next check of my custom view onAttachedToWindow method always returns false

private class MyTextureView extends TextureView
{
    public MyTextureView(Context context) {
        super(context);
    }

    @Override
    protected void onAttachedToWindow()
    {
        super.onAttachedToWindow();
        Log.d("", Boolean.toString(mTextureView.isHardwareAccelerated()));          
    }
}

Does anyone know what's wrong here?

thank