Floating action button

A Floating Action Button (FAB) is a high-emphasis button that lets the user perform a primary action in an application. It promotes a single, focused action that is the most common pathway a user might take and is typically found anchored to the bottom right of the screen.

Consider these three use cases where you might use a FAB:

• Create new item: In a note-taking app, a FAB might be used to quickly create a new note.
• Add new contact: In a chat app, a FAB could open an interface that lets the user add someone to a conversation.
• Center location: In a map interface, a FAB could center the map on the user's current location.

In Material Design, there are four types of FAB:

• FAB: A floating action button of ordinary size.
• Small FAB: A smaller floating action button.
• Large FAB: A larger floating action button.
• Extended FAB: A floating action button that contains more than just an icon.

API surface

Although there are several composables you can use to create floating action buttons consistent with Material Design, their parameters don't differ greatly. Among the key parameters you should keep in mind are the following:

• onClick: The function called when the user presses the button.
• containerColor: The color of the button.
• contentColor: The color of the icon.

Floating action button

To create a general floating action button, use the basic FloatingActionButton composable. The following example demonstrates a basic implementation of a FAB:

@Composable
funExample(onClick:()->Unit){
FloatingActionButton(
onClick={onClick()},
){
Icon(Icons.Filled.Add,"Floating action button.")
}
}
FloatingActionButton.kt 

This implementation appears as follows:

Small button

To create a small floating action button, use the SmallFloatingActionButton composable. The following example demonstrates how to do so, with the addition of custom colors.

@Composable
funSmallExample(onClick:()->Unit){
SmallFloatingActionButton(
onClick={onClick()},
containerColor=MaterialTheme.colorScheme.secondaryContainer,
contentColor=MaterialTheme.colorScheme.secondary
){
Icon(Icons.Filled.Add,"Small floating action button.")
}
}
FloatingActionButton.kt 

This implementation appears as follows:

Large button

To create a large floating action button, use the LargeFloatingActionButton composable. This composable is not significantly different from the other examples aside from the fact that it results in a bigger button.

The following is a straightforward implementation of a large FAB.

@Composable
funLargeExample(onClick:()->Unit){
LargeFloatingActionButton(
onClick={onClick()},
shape=CircleShape,
){
Icon(Icons.Filled.Add,"Large floating action button")
}
}
FloatingActionButton.kt 

This implementation appears as follows:

Extended button

You can create more complex floating action buttons with the ExtendedFloatingActionButton composable. The key difference between it and FloatingActionButton is that it has dedicated icon and text parameters. They let you create a button with more complex content that scales to fit its content appropriately.

The following snippet demonstrates how to implement ExtendedFloatingActionButton, with example values passed for icon and text.

@Composable
funExtendedExample(onClick:()->Unit){
ExtendedFloatingActionButton(
onClick={onClick()},
icon={Icon(Icons.Filled.Edit,"Extended floating action button.")},
text={Text(text="Extended FAB")},
)
}
FloatingActionButton.kt 

This implementation appears as follows:

Additional resources

• Common buttons
• Material UI docs