NullPointerException, call beginFakeDrag before fakeDragBy

[logan676]

ViewPagerIndicator/library/src/com/viewpagerindicator/CirclePageIndicator.java

Line 309 in 8cd549f

if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) {

java.lang.NullPointerException:   Attempt to invoke virtual method 'void   android.view.VelocityTracker.addMovement(android.view.MotionEvent)' on a null   object reference\n\tat   android.support.v4.view.ViewPager.fakeDragBy(SourceFile:2644)\n\tat   com.xxx.xxx.ui.widget.aj.onTouchEvent(SourceFile:296)\n\tat   android.view.View.dispatchTouchEvent(View.java:9414)\n\tat