DateTimePicker 设置年月日时分和年月日之间进行切换

使用DatimeWheelLayout，想通过改变wheel_timeMode值进行切换，将wheel_timeMode改为none时，时分滚轮只是隐藏了，但是依旧占据位置，改变DatimeWheelLayout的宽度也没用，需要整体居中显示，也没办法设置每个滚轮的宽度

Start by locating DatimeWheelLayout and the wheel_timeMode handling, then reproduce switching between date-time and date-only modes. Check how hidden time wheels affect layout width and how wheel widths are assigned. Done means date-only mode is centered without reserved space and each wheel's width can be configured.

Written by the indexing model from the issue text.