Mask gets deleted when entering special characters in a numeric MaskedEditText

[SanjayGubaju]

Special characters includes Spaces, Asterisk,Minus, Plus....... etc. Results in app crash...

[gmk57]

Crashes with IndexOutOfBoundsException. Example stack traces:

java.lang.IndexOutOfBoundsException: charAt: 17 >= length 17
    at android.text.SpannableStringBuilder.charAt(SpannableStringBuilder.java:116)
    at com.github.pinball83.maskededittext.MaskedEditText.getUnmaskedText(MaskedEditText.java:206)
    at com.github.pinball83.maskededittext.MaskedEditText.onTouch(MaskedEditText.java:318)

java.lang.IndexOutOfBoundsException: replace (8 ... 9) ends beyond length 8
    at android.text.SpannableStringBuilder.checkRange(SpannableStringBuilder.java:1018)
    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:460)
    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:454)
    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:33)
    at com.github.pinball83.maskededittext.MaskedEditText$MaskedInputFilter.filter(MaskedEditText.java:375)

java.lang.IndexOutOfBoundsException: setSpan (7 ... 7) ends beyond length 6
    at android.text.SpannableStringBuilder.checkRange(SpannableStringBuilder.java:1018)
    at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:611)
    at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:607)
    at android.text.Selection.setSelection(Selection.java:76)
    at android.text.Selection.setSelection(Selection.java:87)
    at android.widget.EditText.setSelection(EditText.java:99)
    at com.github.pinball83.maskededittext.MaskedEditText$MaskedInputFilter.skipSymbol(MaskedEditText.java:421)
    at com.github.pinball83.maskededittext.MaskedEditText$MaskedInputFilter.filter(MaskedEditText.java:384)