Android: how to check if a View inside of ScrollView is visible?

This extension help detect view fully visible.
It also work if your View is a child of child of ... of ScrollView (eg: ScrollView -> LinearLayout -> ContraintLayout -> ... -> YourView).

fun ScrollView.isViewVisible(view: View): Boolean {
    val scrollBounds = Rect()
    this.getDrawingRect(scrollBounds)
    var top = 0f
    var temp = view
    while (temp !is ScrollView){
        top += (temp).y
        temp = temp.parent as View
    }
    val bottom = top + view.height
    return scrollBounds.top < top && scrollBounds.bottom > bottom
}

Note

1) view.getY() and view.getX() return the x,y value to FIRST PARENT.

2) Here is example about how getDrawingRect will return Link

Use View#getHitRect instead of View#getDrawingRect on the view you're testing. You can use View#getDrawingRect on the ScrollView instead of calculating explicitly.

Code from View#getDrawingRect:

 public void getDrawingRect(Rect outRect) {
        outRect.left = mScrollX;
        outRect.top = mScrollY;
        outRect.right = mScrollX + (mRight - mLeft);
        outRect.bottom = mScrollY + (mBottom - mTop);
 }

Code from View#getHitRect:

public void getHitRect(Rect outRect) {
        outRect.set(mLeft, mTop, mRight, mBottom);
}

This works:

Rect scrollBounds = new Rect();
scrollView.getHitRect(scrollBounds);
if (imageView.getLocalVisibleRect(scrollBounds)) {
    // Any portion of the imageView, even a single pixel, is within the visible window
} else {
    // NONE of the imageView is within the visible window
}

If you want to detect that the view is FULLY visible:

private boolean isViewVisible(View view) {
    Rect scrollBounds = new Rect();
    mScrollView.getDrawingRect(scrollBounds);

    float top = view.getY();
    float bottom = top + view.getHeight();

    if (scrollBounds.top < top && scrollBounds.bottom > bottom) {
        return true;
    } else {
        return false;
    }
}