CODEWITHSUNDEEP
javascrolllibgdxdrag
Grinning Trout
Grinning Trout

Reputation: 119

Scroll up and down by drag the table

 table1.addListener(new InputListener(){
        @Override
        public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
           scroll=y;
            System.out.print(scroll);
            return true;
        }

        @Override
        public void touchDragged(InputEvent event, float x, float y, int pointer) {

            table1.setPosition((scroll+(y)));
        }});

I want to scroll my table up and down by dragging my table (like Facebook on phone) I can't make this math thing on the Y I don't know why when I drag it it goes crazy.

Upvotes: 2

Views: 137

Answers (1)

Arctic45
Arctic45

Reputation: 1098

Parameters x and y in the methods of InputListener are local coordinates (i.e. relative to your table), so you need to convert them to table's parent coordinate system:

table.addListener(new InputListener() {

    Vector2 vec = new Vector2();

    @Override
    public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
        table.localToParentCoordinates(vec.set(x, y));
        return true;
    }

    @Override
    public void touchDragged(InputEvent event, float x, float y, int pointer) {
        float oldTouchY = vec.y;
        table.localToParentCoordinates(vec.set(x, y));
        table.moveBy(0f, vec.y - oldTouchY);
    }
});

By the way, using ScrollPane will probably be much better and convenient solution in your case: https://github.com/libgdx/libgdx/wiki/Scene2d.ui#scrollpane

Upd:

Actually, since you only need deltaY you can do this without converting coordinates:

table.addListener(new InputListener() {

    float touchY;

    @Override
    public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
        touchY = y;
        return true;
    }

    @Override
    public void touchDragged(InputEvent event, float x, float y, int pointer) {
        // since you move your table along with pointer, your touchY will be the same in table's local coordinates
        float deltaY = y - touchY;
        table.moveBy(0f, deltaY);
    }
});

Upvotes: 2

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