LazyColumn for lists in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a LazyColumn in Jetpack Compose?

LazyColumn is a vertically scrolling list that only composes and lays out the visible items, improving performance for long lists.

beginner

How do you add items to a LazyColumn?

You use the items() function inside LazyColumn to provide a list of data and a composable for each item.

intermediate

Why is LazyColumn preferred over Column for long lists?

Because LazyColumn only creates the visible items, it uses less memory and CPU, making scrolling smooth even with many items.

intermediate

What parameter helps LazyColumn remember scroll position?

The state parameter with a LazyListState object helps remember and control scroll position.

beginner

How can you add spacing between items in a LazyColumn?

You can add spacing by using the verticalArrangement = Arrangement.spacedBy(8.dp) parameter inside LazyColumn.

What does LazyColumn do differently than a regular Column?

A Preloads all items at once

B Displays items horizontally

C Automatically sorts list items

D Only composes visible items to improve performance

LazyColumn only composes and lays out the items currently visible on screen, unlike Column which composes all children.

Which function is used inside LazyColumn to display a list of data?

A items()

B listOf()

C forEach()

D map()

The items() function takes a list and a composable lambda to display each item in LazyColumn.

How do you add vertical space between items in LazyColumn?

A Use horizontalArrangement

B Use verticalArrangement = Arrangement.spacedBy()

C Add padding to each item manually

D Wrap items in a Spacer composable

verticalArrangement = Arrangement.spacedBy() adds consistent vertical spacing between items.

What type of state object helps control scroll position in LazyColumn?

A MutableState

B ScrollState

C LazyListState

D ViewModelState

LazyListState is designed to track and control the scroll position of LazyColumn.

Which of these is NOT a benefit of using LazyColumn?

A Automatically sorts list items alphabetically

B Improved performance for large lists

C Only visible items are composed

D Automatic item recycling

LazyColumn does not sort items; sorting must be done before passing data.

Explain how LazyColumn improves performance when displaying long lists.

Think about what happens when you scroll a long list on your phone.

Describe how to add a list of strings to a LazyColumn with spacing between items.

Remember the parameters inside LazyColumn and how you display each item.