NullPointer in SubsamplingScaleImageView.onDraw()

[tobsinger]

Hi,

first of all thank you for this very nice project. I really appreciate the work. Currently I am facing an error during the draw process of the SubsamplingScaleImageView.

It happens in this line:

float vFocusNowX = this.ease(this.anim.easing, scaleElapsed, this.anim.vFocusStart.x, this.anim.vFocusEnd.x - this.anim.vFocusStart.x, this.anim.duration);

java.lang.NullPointerException: Attempt to read from field 'float android.graphics.PointF.x' on a null object reference
                                                                    at com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView.onDraw(SubsamplingScaleImageView.java:969)

I already debugged into the line and figured out that this.anim.vFocusStart is null. Maybe a simple nullcheck before the call will fix the issue.

Thank you and keep up the good work.

[davemorrissey]

It's hard to see how this would happen in normal use. Can you describe when it happens, whether it's before load, after load, on touch, drag, zoom, fling, custom animation or whatever?

I think the only way vFocusStart can be null is the anim was started some time after it was constructed, and the view was reset in the meantime. I can guard against that but it would be good to know what the real cause is.

[davemorrissey]

I've added a basic fix for the NPE but not addressed any possible root cause. I suspect when this NPE happens the view is in a reset or loading state so the animation can be safely ignored. If you do find why this was happening let me know!