Look at almost any business app in Ghana, from a pharmacy stock app to an NGO survey tool, and you will find the same three things: a list of items, a form to add or edit them, and a way to move between screens. Master these and you can build the core of most real apps.
Long lists with ListView.builder
A shop might have five hundred products. Building five hundred widgets at once would waste memory on a modest phone. ListView.builder only builds the rows that are visible on screen, and builds more as the user scrolls:
ListView.builder(
itemCount: products.length,
itemBuilder: (context, i) {
final p = products[i];
return ListTile(
title: Text(p.name),
subtitle: Text('GHS ${p.price}'),
onTap: () => openDetail(p),
);
},
)ListTile is a ready made row with a title, subtitle and optional icons. Use it often; it already follows good spacing and touch target sizes.
Forms that check their input
A Form groups input fields so you can check them all at once. Each TextFormField can have a validator function that returns an error message, or null if the value is fine: