如何刷新CalenderView日期上的listView日期已更改

I want to syne my listView with my CalenderView so that when a new date is selected on the calender is changed only appointments that have a date that equals the date on the calendar view are displayed.I am using Firebase realtime database and the only way i thought of geting this to work is update the database each time a selection is made but i dont think this is the optimal/correct way to do it. i have attached the class below if any other classes are needed i can add them too. I have attached an image of the screen too for some clarity. Thanks in advanceI want to syne my listView with my CalenderView