How to find the swipe direction of PageSlider while the user starts swiping the page in HarmonyOS?

Question

I am writing a custom component in HarmonyOS using Java SDK and it is a custom page slider indicator. To do that I have added a PageChangedListener which provides three override methods.

public class CustomPageSliderIndicator extends Component implements PageSlider.PageChangedListener{

@Override
public void onPageSliding(int position, float positionOffset, int positionOffsetPixels) {}

@Override
public void onPageChosen(int i) {}

@Override
public void onPageSlideStateChanged(int i) { }
}

Whenever the user slides a page, onPageSliding will be called, here I am facing the problem that the position and positionOffset are the same for sliding right and left.

So, how to know the direction of sliding?

Answer 1

Introduce an instance variable (currentPosition) to keep track of the current page.

    private int currentPosition;

...

    pageSlider.addPageChangedListener(new PageSlider.PageChangedListener() {
                    @Override
                    public void onPageSliding(int itemPos, float itemPosOffset, int itemPosOffsetPixels) {
                    }

                    @Override
                    public void onPageSlideStateChanged(int state) {
                    }

                    @Override
                    public void onPageChosen(int position) {
                         if(currentPosition < position) {
                            // handle swipe LEFT
                        } else if(currentPosition > position){
                            // handle swipe RIGHT
                        }
                        currentPosition = position; // Update current position
                    }
                });