NPE in view runnable

[vcoolish]

https://github.com/konaire/NumericKeyboard/blob/master/numeric-keyboard/src/main/java/com/konaire/numerickeyboard/NumericKeyboard.kt#L35

at some point 'this' becomes null, need to handle this case

java.lang.NullPointerException: 
  at com.konaire.numerickeyboard.NumericKeyboard$removeChar$1.run (NumericKeyboard.kt:39)
  at android.os.Handler.handleCallback (Handler.java:938)
  at android.os.Handler.dispatchMessage (Handler.java:99)
  at android.os.Looper.loopOnce (Looper.java:226)
  at android.os.Looper.loop (Looper.java:313)
  at android.app.ActivityThread.main (ActivityThread.java:8663)
  at java.lang.reflect.Method.invoke (Native Method)
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:567)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1135)

[Mojtaba-Shafaei]

I got the NPE too, like @vcoolish

handler.postDelayed(this, 50) inside the runnable throws NPE
I guess the "postDelayed" was executed after onStop, so, the activity is no longer alive

private val removeChar: ViewRunnable = object : ViewRunnable() {
        override fun run() {
            val listener = KeyClickListener(field, fieldMaxLength)

            listener.onClick(view)
            handler.postDelayed(this, 50)
        }
    }