JavaFX TableView ScrollBar值说明

Question

Could anyone explain what vertical scroll bar value means? For example, there is a table with 100 rows. View port can show only 10 rows. For example rows 26-35 are shown. What will be value of scroll bar and how it is calculated?

Answer 1

Assuming all rows are the same height:

A scroll bar has a min , max , and value . If your viewport shows 10 rows and the table has 100 items, then it can be scrolled vertically a total of 90 rows (at one end, showing rows 1-10, and at the other, showing rows 91-100). If it shows 26-35 then it has scrolled 25 rows, so you will have

(value - min) / (max - min) = 25/90

or

value = min + 25*(max - min) / 90

The default min and max are 0 and 1 , respectively, so with those defaults this would be

value = 25 /90 = 0.277778