CODEWITHSUNDEEP
javaswingjscrollpane
Stanislav
Stanislav

Reputation: 425

JScrollpane: scroll only by unitIncrement

I created JPanel with implemented Scrollable interface and overrided method getScrollableBlockIncrement. I placed JPanel into JScrollPane. And JPanel contains several components with same height. This height is the unitIncrement. Now, when I click on arrow on the vertical scrollbar, viewport moves by unitIncrement. But, when I move knob with mouse, viewport moves by pixels. How to make viewport to move only by unitIncrement?

Update:
Knob is the middle button on scrollbar, on track, to drag it. As shown there How a Scroll Pane Works

I want viewport moves only by unitIncrement in any way. Also when I press left mouse button on knob and drag it. The example behaviour: intellisense in Eclipse.

Update 2:
I tried myJScrollPane.getVerticalScrollBar().setUnitIncrement(16); And didn't get desired behaviour.
When I debugged code, I found that parameter unitIncrement is discarded when I drag the knob.

Update 3:
Couldn't find suitable solution with JScrollPane and wrote custom scroll pane.

Upvotes: 0

Views: 723

Answers (1)

Nick Rippe
Nick Rippe

Reputation: 6475

The answer to your question could be found with a little search effort: How do I speed up the scroll speed in a JScrollPane when using the mouse wheel?

To reiterate, you basically want to modify the JScrollBar on your JScollPane.

myJScrollPane.getVerticalScrollBar().setUnitIncrement(16);

Otherwise, you're left with overriding the Scolling event on the JScrollPane to pass in the amount you want to scroll based on the pane that's being scrolled - that's a little messy... so if the first way works for you, that's what I'd go with.

Bottom line: the problem's with JScollPane - not your Scrollable class.

Upvotes: 0

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