LoopView：因List内无元素，便没有setDataList，滑动LoopView区域，会有异常（传入无元素List也会有异常）；

[crDemons]

java.lang.NullPointerException: Attempt to invoke virtual method 'int java.util.ArrayList.size()' on a null object reference at com.bruce.pickerview.LoopView$LoopViewGestureListener.onScroll(LoopView.java:433) at android.view.GestureDetector.onTouchEvent(GestureDetector.java:611) at com.bruce.pickerview.LoopView.onTouchEvent(LoopView.java:334) at android.view.View.dispatchTouchEvent(View.java:11776) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657) at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:448) at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1829) at android.app.Dialog.dispatchTouchEvent(Dialog.java:815) at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:410) at android.view.View.dispatchPointerEvent(View.java:12015) at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4795) at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4609) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4147) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4200) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4166) at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4293) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4174) at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4350) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4147) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4200) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4166) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4174) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4147) at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6661) at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6635) at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6596) at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6764) at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:186) at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method) at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:177) at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:6735) at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:6787) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:911) at android.view.Choreographer.doCallbacks(Choreographer.java:723) at android.view.Choreographer.doFrame(Choreographer.java:652) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:897) at android.os.Handler.handleCallback(Handler.java:790) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:164) at android.app.ActivityThread.main(ActivityThread.java:6494) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

目前我在无元素时LoopView区域INVISIBLE，期待源码早日修复；