활동에서 ViewPager 조각의 메서드를 호출하는 방법은 무엇입니까?

<code class="java">class PagerAdapter extends FragmentPagerAdapter {
    public Fragment[] fragments;

    // Instantiate fragments and add to array
    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        Fragment createdFragment = (Fragment) super.instantiateItem(container, position);
        fragments[position] = createdFragment;
        return createdFragment;
    }
}</code>

<code class="java">viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
    @Override
    public void onPageSelected(int position) {
        Fragment frag = mAdapter.fragments[position];
        if (frag != null &amp;&amp; frag instanceof FragmentTwo) {
            ((FragmentTwo)frag).sendGetRequest();
        }
    }
});</code>

<code class="kotlin">viewPager.registerOnPageChangeCallback(
    object: ViewPager2.OnPageChangeCallback() {
        override fun onPageSelected(position: Int) {
            super.onPageSelected(position)
            val frag: Fragment = mAdapter.fragments[position]
            if (frag != null &amp;&amp; frag is FragmentTwo) {
                (frag as FragmentTwo).sendGetRequest()
            }
        }
    }
)</code>