package com.github.aakira.expandablelayout;

public abstract class ExpandableLayoutListenerAdapter implements ExpandableLayoutListener {
    /**
     * {@inheritDoc}
     */
    @Override
    public void onAnimationStart() {
    }

    /**
     * {@inheritDoc}
     */
    public void onAnimationEnd() {
    }

    /**
     * {@inheritDoc}
     */
    public void onPreOpen() {
    }

    /**
     * {@inheritDoc}
     */
    public void onPreClose() {
    }

    /**
     * {@inheritDoc}
     */
    public void onOpened() {
    }

    /**
     * {@inheritDoc}
     */
    public void onClosed() {
    }
}
package com.github.aakira.expandablelayout;

public abstract class ExpandableLayoutListenerAdapter implements ExpandableLayoutListener {
    /**
     * {@inheritDoc}
     */
    @Override
    public void onAnimationStart() {
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onAnimationEnd() {
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onPreOpen() {
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onPreClose() {
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onOpened() {
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onClosed() {
    }
}
Add override annotations in ExpandableLayoutListenerAdapter.