CODEWITHSUNDEEP
androidandroid-layoutuiscrollviewscrollviewhorizontalscrollview
Shubham Agarwal Bhewanewala
Shubham Agarwal Bhewanewala

Reputation: 1119

Want to scroll a ScrollView parallely when another ScrollView is scrolled

I have created two ScrollView in same layout. You can say a parallel scrollview. I want to scroll one scrollview manually and in response another scrollview should scroll exactly same way. Scroll length for both view is same. This should happen same for both the scrollviews. I tried a code for this.

horizontalScrollViewB.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
            @Override
            public void onScrollChanged() {
                horizontalScrollViewD.scrollTo(horizontalScrollViewB.getScrollX(), horizontalScrollViewB.getScrollY());
            }
        });
        horizontalScrollViewD.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
            @Override
            public void onScrollChanged() {
                horizontalScrollViewB.scrollTo(horizontalScrollViewD.getScrollX(), horizontalScrollViewD.getScrollY());
            }
        });

Here what happened is for the first "B" scrollview it works fine but for "D" scrollview it creates problem in scrolling. I understand the problem but couldnot get the solution. So what should I do to avoid one's call when another is calling "onScrollChangeListener()".

Upvotes: 1

Views: 63

Answers (1)

Shubham Bhewanewala
Shubham Bhewanewala

Reputation: 597

Override HorizontalView class

package com.example.shaby.payshare;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.HorizontalScrollView;

/**
 * Created by shaby on 3/7/2017.
 */

public class HorizontalScroll extends HorizontalScrollView {

    private ScrollViewListener scrollViewListener = null;
    public interface ScrollViewListener {

        void onScrollChanged(HorizontalScroll scrollView, int x, int y, int oldx, int oldy);

    }
    public HorizontalScroll(Context context) {
        super(context);
    }

    public HorizontalScroll(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public HorizontalScroll(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public void setScrollViewListener(ScrollViewListener scrollViewListener) {
        this.scrollViewListener = scrollViewListener;
    }

    @Override
    protected void onScrollChanged(int x, int y, int oldx, int oldy) {
        super.onScrollChanged(x, y, oldx, oldy);
        if(scrollViewListener != null) {
            scrollViewListener.onScrollChanged(this, x, y, oldx, oldy);
        }
    }
}

Implement the interface in your required class

Upvotes: 1

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