ScrollView with a OnBottomReachedListener for Android. MIT license (https://opensource.org/licenses/MIT).

InteractiveScrollView.java

package se.marteinn.ui;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.ScrollView;


/**
 * Triggers a event when scrolling reaches bottom.
 *
 * Created by martinsandstrom on 2010-05-12.
 * Updated by martinsandstrom on 2014-07-22.
 *
 * Usage:
 *
 *  scrollView.setOnBottomReachedListener(
 *      new InteractiveScrollView.OnBottomReachedListener() {
 *          @Override
 *          public void onBottomReached() {
 *              // do something
 *          }
 *      }
 *  );
 * 
 *
 * Include in layout:
 *  
 *  <se.marteinn.ui.InteractiveScrollView
 *      android:layout_width="match_parent"
 *      android:layout_height="match_parent" />
 *  
 */
public class InteractiveScrollView extends ScrollView {
    OnBottomReachedListener mListener;

    public InteractiveScrollView(Context context, AttributeSet attrs,
            int defStyle) {
        super(context, attrs, defStyle);
    }

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

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

    @Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        View view = (View) getChildAt(getChildCount()-1);
        int diff = (view.getBottom()-(getHeight()+getScrollY()));
        
        if (diff == 0 && mListener != null) {
            mListener.onBottomReached();
        }

        super.onScrollChanged(l, t, oldl, oldt);
    }


    // Getters & Setters

    public OnBottomReachedListener getOnBottomReachedListener() {
        return mListener;
    }

    public void setOnBottomReachedListener(
            OnBottomReachedListener onBottomReachedListener) {
        mListener = onBottomReachedListener;
    }
    

    /**
     * Event listener.
     */
    public interface OnBottomReachedListener{
        public void onBottomReached();
    }
    
}

@marteinn Under which license do you publish this?

@Croydon MIT. Will clarify in the description.

One-liner in Kotlin:

fun ViewGroup.isScrolledToBottom() = getChildAt(childCount - 1).bottom - height - scrollY == 0

good, it's work

topReach is fired multiple times

fixed version

public class MyScrollView extends ScrollView {

OnBottomReachedListener mListener;

private boolean bottomreached = false;

public MyStickyScrollView(Context context, AttributeSet attrs,
                          int defStyle) {
    super(context, attrs, defStyle);
}

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

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

@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
    View view = getChildAt(getChildCount()-1);
    int diff = (view.getBottom()-(getHeight()+getScrollY()));

    if (diff == 0 && mListener != null && !bottomreached) {
        mListener.onBottomReached();
        bottomreached = true;
    }
    else {
        bottomreached = false;
    }

    super.onScrollChanged(l, t, oldl, oldt);
}

// Getters & Setters
public OnBottomReachedListener getOnBottomReachedListener() {
    return mListener;
}

public void setOnBottomReachedListener(
        OnBottomReachedListener onBottomReachedListener) {
    mListener = onBottomReachedListener;
}


/**
 * Event listener.
 */
public interface OnBottomReachedListener{
    void onBottomReached();
}

}
only fires 1 time

diff ==0 is dangerous because it may never hit 0 as of various brand screen configurations. diff <= 0 is kinda useless because it's gonna trigger top/bottomReached multiple times.

So far, great thanks for your work, works just as expected.