ã kotlin properties ObservableProperty V ReadWriteProperty Any initialValue value afterChange Unit property reflect KProperty oldValue newValue beforeChange Boolean getValue thisRef setValue toString StringH            ¸ "»&*B(J2 (2 (2(8HJ2 (2 (2(8HJ2(2 (8H–J2(2 (2(8H–J8HRHX‚ò. 0 H 0 8 0 0 0 0