The exceptions of nullable field

[yunlinos]

Many field are nullable, but use !! in the calling place, which is very unsafe and easily lead to exceptions or crashes. such as:

W/System.err: java.lang.NullPointerException
W/System.err: at com.dragonbones.animation.AnimationState.getAnimationData(AnimationState.kt:1501)
W/System.err: at com.dragonbones.animation.Animation.advanceTime(Animation.kt:209)
W/System.err: at com.dragonbones.armature.Armature._advanceTime(Armature.kt:338)
W/System.err: at com.dragonbones.armature.Armature.advanceTime(Armature.kt:310)
W/System.err: at com.soywiz.korge.dragonbones.KorgeDbArmatureDisplay$1.invoke-eeKXlv4(KorgeDbArmatureDisplay.kt:67)
W/System.err: at com.soywiz.korge.dragonbones.KorgeDbArmatureDisplay$1.invoke(KorgeDbArmatureDisplay.kt:64)
W/System.err: at com.soywiz.korge.view.ViewKt$addUpdater$component$1.update-_rozLdE(View.kt:1648)
W/System.err: at com.soywiz.korge.view.ViewsKt.updateSingleViewWithViewsAll-rsF1gfE(Views.kt:644)
W/System.err: at com.soywiz.korge.view.Views.update-_rozLdE(Views.kt:412)
W/System.err: at com.soywiz.korge.view.Views.frameUpdateAndRender-_rozLdE(Views.kt:400)
W/System.err: at com.soywiz.korge.Korge$prepareViewsBase$15.invoke(Korge.kt:527)
W/System.err: at com.soywiz.korge.Korge$prepareViewsBase$15.invoke(Korge.kt:518)
W/System.err: at com.soywiz.korev.EventDispatcher$Mixin.dispatch(EventDispatcher.kt:50)
W/System.err: at com.soywiz.korgw.GameWindow.dispatchRenderEvent(GameWindow.kt:985)
W/System.err: at com.soywiz.korgw.GameWindow.frameRender(GameWindow.kt:580)
W/System.err: at com.soywiz.korgw.GameWindow.frame-LZ20uQo(GameWindow.kt:550)
W/System.err: at com.soywiz.korgw.GameWindow.frame-LZ20uQo$default(GameWindow.kt:547)

The above exception has a very low probability of occurrence, and there is no recurrence path.