package Ġb z . or on . rx li ved ata app Ċ Ċ import Ġandroid . arch . lifecycle . Mutable LiveData Ċ import Ġandroid . support . v 7 . app . AppCompatActivity Ċ import Ġandroid . os . Bundle Ċ import Ġb z . or on . rx li ved ata . filter Null Ċ Ċ class ĠMainActivity Ġ: ĠAppCompatActivity () Ġ{ ĊĊĠ Ġoverride Ġfun ĠonCreate ( savedInstanceState : ĠBundle ?) Ġ{ ĊĠĠĠ Ġsuper . onCreate ( savedInstanceState ) ĊĠĠĠ ĠsetContentView ( R . layout . activity _ main ) ĊĊĠĠĠ Ġval Ġor on Ġ= ĠMutable LiveData < String >() ĊĠĠĠ Ġor on . filter Null () ĊĠ Ġ} Ċ } Ċ