#4 Fix crash due to position NaN in ViewPager PageTransformer

[omtodkar]

In some cases CardSliderTransformer#scalingEquation doesn't return valid Float.

// gives position NaN in some cases
override fun transformPage(page: View, position: Float)

The following line throws an error when trying to assign NaN as elevation.

// This will be during transformation
(page as CardView).cardElevation =
       scalingEquation(viewPager.minShadow, viewPager.baseShadow, absPosition)

private fun scalingEquation(minValue: Float, maxValue: Float, absPosition: Float) =
        (minValue - maxValue) * absPosition + maxValue

Stacktrace as per the Logcat

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.taglr.debug, PID: 5855
    java.lang.IllegalArgumentException: Cannot set 'elevation' to Float.NaN
        at android.view.View.sanitizeFloatPropertyValue(View.java:17041)
        at android.view.View.sanitizeFloatPropertyValue(View.java:17015)
        at android.view.View.setElevation(View.java:17137)
        at androidx.cardview.widget.CardViewApi21Impl.setElevation(CardViewApi21Impl.java:78)
        at androidx.cardview.widget.CardView.setCardElevation(CardView.java:376)
        at com.github.islamkhsh.CardSliderTransformer.transformPage(CardSliderTransformer.kt:40)
        at androidx.viewpager.widget.ViewPager.onPageScrolled(ViewPager.java:1915)
        at androidx.viewpager.widget.ViewPager.pageScrolled(ViewPager.java:1842)
        at androidx.viewpager.widget.ViewPager.scrollToItem(ViewPager.java:694)
        at androidx.viewpager.widget.ViewPager.onLayout(ViewPager.java:1786)
        at android.view.View.layout(View.java:22509)
        at android.view.ViewGroup.layout(ViewGroup.java:7190)
        at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
        at android.view.View.layout(View.java:22509)
        at android.view.ViewGroup.layout(ViewGroup.java:7190)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
        at android.view.View.layout(View.java:22509)
        at android.view.ViewGroup.layout(ViewGroup.java:7190)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.layoutDecoratedWithMargins(RecyclerView.java:9555)
        at androidx.recyclerview.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:690)
        at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
        at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
        at androidx.recyclerview.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4115)
        at androidx.recyclerview.widget.RecyclerView.onMeasure(RecyclerView.java:3521)
        at android.view.View.measure(View.java:25056)
        at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:25056)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:7745)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at androidx.cardview.widget.CardView.onMeasure(CardView.java:260)
        at android.view.View.measure(View.java:25056)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.measureChildWithMargins(RecyclerView.java:9352)
        at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1653)
        at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
        at androidx.recyclerview.widget.LinearLayoutManager.scrollBy(LinearLayoutManager.java:1391)
        at androidx.recyclerview.widget.LinearLayoutManager.scrollVerticallyBy(LinearLayoutManager.java:1128)
        at androidx.recyclerview.widget.RecyclerView.scrollStep(RecyclerView.java:1855)
        at androidx.recyclerview.widget.RecyclerView$ViewFlinger.run(RecyclerView.java:5281)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:988)
        at android.view.Choreographer.doCallbacks(Choreographer.java:765)
        at android.view.Choreographer.doFrame(Choreographer.java:697)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:967)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:216)
        at android.app.ActivityThread.main(ActivityThread.java:7285)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:975)