crash when rillpe finishes

With this layout

<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:keepScreenOn="true">

    <com.andexert.library.RippleView
        android:id="@+id/ripple_view"
        android:layout_width="@dimen/size_l"
        android:layout_height="@dimen/size_l"
        android:layout_gravity="center"
        android:layout_margin="@dimen/margin_m"
        rv_centered="true">

        <Button
            style="@style/Base.Widget.AppCompat.Button.Borderless"
            android:layout_width="match_parent"
            android:layout_margin="@dimen/margin_s"
            android:layout_height="match_parent"
            android:text="xxx"/>

    </com.andexert.library.RippleView>

</FrameLayout>

After tap at Button, when ripple animation finishes i got this exception:

11-16 17:07:52.128 E/AndroidRuntime: FATAL EXCEPTION: main
                                     Process: com.axxonsoft.livestream, PID: 21412
                                     java.lang.IllegalStateException: Underflow in restore - more restores than saves
                                         at android.graphics.Canvas.native_restore(Native Method)
                                         at android.graphics.Canvas.restore(Canvas.java:540)
                                         at com.andexert.library.RippleView.draw(RippleView.java:166)
                                         at android.view.View.updateDisplayListIfDirty(View.java:15198)
                                         at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3594)
                                         at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3574)
                                         at android.view.View.updateDisplayListIfDirty(View.java:15158)
                                         at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3594)
                                         at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3574)
                                         at android.view.View.updateDisplayListIfDirty(View.java:15158)
                                         at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3594)
                                         at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3574)
                                         at android.view.View.updateDisplayListIfDirty(View.java:15158)
                                         at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3594)
                                         at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3574)
                                         at android.view.View.updateDisplayListIfDirty(View.java:15158)
                                         at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3594)
                                         at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3574)
                                         at android.view.View.updateDisplayListIfDirty(View.java:15158)
                                         at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3594)
                                         at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3574)
                                         at android.view.View.updateDisplayListIfDirty(View.java:15158)
                                         at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:283)
                                         at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:289)
                                         at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:324)
                                         at android.view.ViewRootImpl.draw(ViewRootImpl.java:2642)
                                         at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2461)
                                         at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2094)
                                         at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1134)
                                         at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6050)
                                         at android.view.Choreographer$CallbackRecord.run(Choreographer.java:860)
                                         at android.view.Choreographer.doCallbacks(Choreographer.java:672)
                                         at android.view.Choreographer.doFrame(Choreographer.java:608)
                                         at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:846)
                                         at android.os.Handler.handleCallback(Handler.java:742)
                                         at android.os.Handler.dispatchMessage(Handler.java:95)
                                         at android.os.Looper.loop(Looper.java:154)
                                         at android.app.ActivityThread.main(ActivityThread.java:5529)
                                         at java.lang.reflect.Method.invoke(Native Method)
                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629)

traex / RippleEffect

crash when rillpe finishes #132