How to Center Vertically an item in a Stack in Flutter

The simplest and most reliable layout is a Row, which already aligns children horizontally, and you can control the vertical centering with crossAxisAlignment. Don’t use Stack unless you must. 

✅ Recommended Layout

Row(
  mainAxisAlignment: MainAxisAlignment.spaceBetween,
  crossAxisAlignment: CrossAxisAlignment.center, // ensures vertical centering
  children: [
    Expanded(
      child: YourMainWidget(),
    ),
    GestureDetector(
      onTap: () {
        print('Icon tapped!');
      },
      child: Icon(Icons.more_vert, size: 24),
    ),
  ],
)

This ensures:

• The icon stays at the end
• Both widgets get their click events
• Everything stays vertically centered

---

If you MUST use a Stack (for overlay UI)

You can do:

Stack(
  children: [
    YourMainWidget(),
    Positioned(
      right: 0,
      top: 0,
      bottom: 0,   // keeps the icon vertically centered
      child: GestureDetector(
        onTap: () => print('Icon tapped'),
        child: Center(
          child: Icon(Icons.more_vert),
        ),
      ),
    ),
  ],
)

This works because setting top:0 and bottom:0 forces the child to match the Stack height, so Center inside keeps the icon vertically centered.