crash：at com.scichart.charting.modifiers.GestureModifierBase.onTouch(SourceFile:80)

java.lang.NullPointerException: Attempt to invoke virtual method ‘boolean android.view.GestureDetector.onTouchEvent(android.view.MotionEvent)’ on a null object reference
at com.scichart.charting.modifiers.GestureModifierBase.onTouch(SourceFile:80)
at com.scichart.core.utility.touch.MotionEventManager.c(SourceFile:140)
at com.scichart.core.utility.touch.MotionEventManager.a(SourceFile:39)
at com.scichart.core.utility.touch.MotionEventManager$a$1.a(SourceFile:224)
at com.scichart.core.utility.touch.MotionEventManager$a$1.execute(SourceFile:221)
at com.scichart.core.utility.touch.MotionEventManager$a.a(SourceFile:211)
at com.scichart.core.utility.touch.MotionEventManager$a.onTouchEvent(SourceFile:183)
at com.scichart.charting.visuals.SciChartSurface.onTouchEvent(SourceFile:1237)
at android.view.View.dispatchTouchEvent(View.java:12533)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3026)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2705)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:461)
at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1830)
at android.app.Activity.dispatchTouchEvent(Activity.java:3453)
at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:419)
at android.view.View.dispatchPointerEvent(View.java:12774)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:5263)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:5063)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4578)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4631)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4597)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4737)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4605)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4794)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4578)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4631)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4597)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4605)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4578)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:7304)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:7273)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:7234)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7410)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:247)
at android.os.MessageQueue.nativePollOnce(Native Method)
at android.os.MessageQueue.next(MessageQueue.java:326)
at android.os.Looper.loop(Looper.java:165)
at android.app.ActivityThread.main(ActivityThread.java:6806)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)