question: @ Override public String filter ( String value , String previousValue ) { if ( previousValue != null && value . length ( ) > previousValue . length ( ) ) return value ; return value . equals ( "0" ) || value . equals ( "0.0" ) ? "" : value ; }
target:  The default filter removes the display of '0' or '0.0' if the user has erased the text. This is to prevent a number being shown when the user tries to erase it.