androidx.compose.foundation.text

In this page, you'll find documentation for types, properties, and functions available in the androidx.compose.foundation.text package such as BasicText, BasicTextFiled, KeyboardActions, and KeyboardOptions.

If you're looking for guidance instead, check out the Text in Compose guide.

Interfaces

`KeyboardActionScope`	This scope can be used to execute the default action implementation.	Cmn
`TextAutoSize`	Interface used by Text composables to override text size to automatically grow or shrink text to fill the layout bounds.	Cmn

Classes

`InlineTextContent`	A data class that stores a composable to be inserted into the text layout.	Cmn
`KeyboardActions`	The `KeyboardActions` class allows developers to specify actions that will be triggered in response to users triggering IME action on the software keyboard.	Cmn
`KeyboardOptions`	The keyboard configuration options for TextFields.	Cmn

Objects

TextAutoSizeDefaults

Contains defaults for TextAutoSize APIs.

Cmn

Annotations

InternalFoundationTextApi

Cmn

Top-level functions summary

`Unit`	@Composable BasicSecureTextField( state: TextFieldState, modifier: Modifier, enabled: Boolean, readOnly: Boolean, inputTransformation: InputTransformation?, textStyle: TextStyle, keyboardOptions: KeyboardOptions, onKeyboardAction: KeyboardActionHandler?, onTextLayout: (Density.(getResult: () -> TextLayoutResult?) -> Unit)?, interactionSource: MutableInteractionSource?, cursorBrush: Brush, decorator: TextFieldDecorator?, textObfuscationMode: TextObfuscationMode, textObfuscationCharacter: Char, scrollState: ScrollState ) BasicSecureTextField is specifically designed for password entry fields and is a preconfigured alternative to `BasicTextField`.	Cmn
`Unit`	`@Composable BasicText( text: String, modifier: Modifier, style: TextStyle, onTextLayout: ((TextLayoutResult) -> Unit)?, overflow: TextOverflow, softWrap: Boolean, maxLines: Int, minLines: Int, color: ColorProducer?, autoSize: TextAutoSize? )` Basic element that displays text and provides semantics / accessibility information.	Cmn
`Unit`	`@Composable BasicText( text: AnnotatedString, modifier: Modifier, style: TextStyle, onTextLayout: ((TextLayoutResult) -> Unit)?, overflow: TextOverflow, softWrap: Boolean, maxLines: Int, minLines: Int, inlineContent: Map<String, InlineTextContent>, color: ColorProducer?, autoSize: TextAutoSize? )` Basic element that displays text and provides semantics / accessibility information.	Cmn
`Unit`	@Composable BasicTextField( state: TextFieldState, modifier: Modifier, enabled: Boolean, readOnly: Boolean, inputTransformation: InputTransformation?, textStyle: TextStyle, keyboardOptions: KeyboardOptions, onKeyboardAction: KeyboardActionHandler?, lineLimits: TextFieldLineLimits, onTextLayout: (Density.(getResult: () -> TextLayoutResult?) -> Unit)?, interactionSource: MutableInteractionSource?, cursorBrush: Brush, outputTransformation: OutputTransformation?, decorator: TextFieldDecorator?, scrollState: ScrollState ) Basic text composable that provides an interactive box that accepts text input through software or hardware keyboard, but provides no decorations like hint or placeholder.	Cmn
`Unit`	@Composable BasicTextField( value: String, onValueChange: (String) -> Unit, modifier: Modifier, enabled: Boolean, readOnly: Boolean, textStyle: TextStyle, keyboardOptions: KeyboardOptions, keyboardActions: KeyboardActions, singleLine: Boolean, maxLines: Int, minLines: Int, visualTransformation: VisualTransformation, onTextLayout: (TextLayoutResult) -> Unit, interactionSource: MutableInteractionSource?, cursorBrush: Brush, decorationBox: @Composable (@Composable innerTextField: () -> Unit) -> Unit ) Basic composable that enables users to edit text via hardware or software keyboard, but provides no decorations like hint or placeholder.	Cmn
`Unit`	@Composable BasicTextField( value: TextFieldValue, onValueChange: (TextFieldValue) -> Unit, modifier: Modifier, enabled: Boolean, readOnly: Boolean, textStyle: TextStyle, keyboardOptions: KeyboardOptions, keyboardActions: KeyboardActions, singleLine: Boolean, maxLines: Int, minLines: Int, visualTransformation: VisualTransformation, onTextLayout: (TextLayoutResult) -> Unit, interactionSource: MutableInteractionSource?, cursorBrush: Brush, decorationBox: @Composable (@Composable innerTextField: () -> Unit) -> Unit ) Basic composable that enables users to edit text via hardware or software keyboard, but provides no decorations like hint or placeholder.	Cmn
`Unit`	`@Composable ClickableText( text: AnnotatedString, modifier: Modifier, style: TextStyle, softWrap: Boolean, overflow: TextOverflow, maxLines: Int, onTextLayout: (TextLayoutResult) -> Unit, onClick: (Int) -> Unit )` This function is deprecated. Use Text or BasicText and pass an AnnotatedString that contains a LinkAnnotation.	Cmn
`KeyboardActions`	`KeyboardActions(onAny: KeyboardActionScope.() -> Unit)` Creates an instance of `KeyboardActions` that uses the specified lambda for all `ImeAction`s.	Cmn

Extension functions summary

Unit

AnnotatedString.Builder.appendInlineContent(
    id: String,
    alternateText: String
)

Used to insert composables into the text layout.

Cmn

Top-level properties summary

`ProvidableCompositionLocal<Brush>`	`LocalAutofillHighlightBrush` CompositionLocal used to change the highlight `Brush` used for autofilled components.	Cmn
`ProvidableCompositionLocal<Color>`	`LocalAutofillHighlightColor` This property is deprecated. Use LocalAutofillHighlightBrush instead.	Cmn
`ProvidableCompositionLocal<Executor?>`	`LocalBackgroundTextMeasurementExecutor` CompositionLocal that provides an Executor for background text processing to potentially get run on.	android

Top-level functions

BasicSecureTextField

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

@Composable
fun BasicSecureTextField(
    state: TextFieldState,
    modifier: Modifier = Modifier,
    enabled: Boolean = true,
    readOnly: Boolean = false,
    inputTransformation: InputTransformation? = null,
    textStyle: TextStyle = TextStyle.Default,
    keyboardOptions: KeyboardOptions = KeyboardOptions.SecureTextField,
    onKeyboardAction: KeyboardActionHandler? = null,
    onTextLayout: (Density.(getResult: () -> TextLayoutResult?) -> Unit)? = null,
    interactionSource: MutableInteractionSource? = null,
    cursorBrush: Brush = SolidColor(Color.Black),
    decorator: TextFieldDecorator? = null,
    textObfuscationMode: TextObfuscationMode = TextObfuscationMode.Default,
    textObfuscationCharacter: Char = DefaultObfuscationCharacter,
    scrollState: ScrollState = rememberScrollState()
): Unit

BasicSecureTextField is specifically designed for password entry fields and is a preconfigured alternative to BasicTextField. It only supports a single line of content and comes with default settings for KeyboardOptions, InputTransformation, and CodepointTransformation that are appropriate for entering secure content. Additionally, some context menu actions like cut, copy, and drag are disabled for added security.

Parameters
`state: TextFieldState`	`TextFieldState` object that holds the internal state of a `BasicSecureTextField`.
`modifier: Modifier = Modifier`	optional `Modifier` for this text field.
`enabled: Boolean = true`	controls the enabled state of the `BasicSecureTextField`. When `false`, the text field will be neither editable nor focusable, the input of the text field will not be selectable.
`readOnly: Boolean = false`	controls the editable state of the `BasicSecureTextField`. When `true`, the text field can not be modified, however, a user can focus on it. Read-only text fields are usually used to display pre-filled forms that a user can not edit.
`inputTransformation: InputTransformation? = null`	Optional `InputTransformation` that will be used to transform changes to the `TextFieldState` made by the user. The transformation will be applied to changes made by hardware and software keyboard events, pasting or dropping text, accessibility services, and tests. The transformation will not be applied when changing the `state` programmatically, or when the transformation is changed. If the transformation is changed on an existing text field, it will be applied to the next user edit. The transformation will not immediately affect the current `state`.
`textStyle: TextStyle = TextStyle.Default`	Style configuration for text content that's displayed in the editor.
`keyboardOptions: KeyboardOptions = KeyboardOptions.SecureTextField`	Software keyboard options that contain configurations such as `KeyboardType` and `ImeAction`. This composable by default configures `KeyboardOptions` for a secure text field by disabling auto correct and setting `KeyboardType` to `KeyboardType.Password`.
`onKeyboardAction: KeyboardActionHandler? = null`	Called when the user presses the action button in the input method editor (IME), or by pressing the enter key on a hardware keyboard. By default this parameter is null, and would execute the default behavior for a received IME Action e.g., `ImeAction.Done` would close the keyboard, `ImeAction.Next` would switch the focus to the next focusable item on the screen.
`onTextLayout: (Density.(getResult: () -> TextLayoutResult?) -> Unit)? = null`	Callback that is executed when the text layout becomes queryable. The callback receives a function that returns a `TextLayoutResult` if the layout can be calculated, or null if it cannot. The function reads the layout result from a snapshot state object, and will invalidate its caller when the layout result changes. A `TextLayoutResult` object contains paragraph information, size of the text, baselines and other details. The callback can be used to add additional decoration or functionality to the text. For example, to draw a cursor or selection around the text. `Density` scope is the one that was used while creating the given text layout.
`interactionSource: MutableInteractionSource? = null`	the `MutableInteractionSource` representing the stream of `Interaction`s for this TextField. You can create and pass in your own remembered `MutableInteractionSource` if you want to observe `Interaction`s and customize the appearance / behavior of this TextField for different `Interaction`s.
`cursorBrush: Brush = SolidColor(Color.Black)`	`Brush` to paint cursor with. If `SolidColor` with `Color.Unspecified` provided, there will be no cursor drawn.
`decorator: TextFieldDecorator? = null`	Allows to add decorations around text field, such as icon, placeholder, helper messages or similar, and automatically increase the hit target area of the text field.
`textObfuscationMode: TextObfuscationMode = TextObfuscationMode.Default`	Determines the method used to obscure the input text.
`textObfuscationCharacter: Char = DefaultObfuscationCharacter`	Which character to use while obfuscating the text. It doesn't have an effect when `textObfuscationMode` is set to `TextObfuscationMode.Visible`.
`scrollState: ScrollState = rememberScrollState()`	The scroll state of the text field. Since `BasicSecureTextField` is always single line, this scroll state always controls a horizontal scroll.

BasicText

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

@Composable
fun BasicText(
    text: String,
    modifier: Modifier = Modifier,
    style: TextStyle = TextStyle.Default,
    onTextLayout: ((TextLayoutResult) -> Unit)? = null,
    overflow: TextOverflow = TextOverflow.Clip,
    softWrap: Boolean = true,
    maxLines: Int = Int.MAX_VALUE,
    minLines: Int = 1,
    color: ColorProducer? = null,
    autoSize: TextAutoSize? = null
): Unit

Basic element that displays text and provides semantics / accessibility information. Typically you will instead want to use androidx.compose.material.Text, which is a higher level Text element that contains semantics and consumes style information from a theme.

Parameters
`text: String`	The text to be displayed.
`modifier: Modifier = Modifier`	`Modifier` to apply to this layout node.
`style: TextStyle = TextStyle.Default`	Style configuration for the text such as color, font, line height etc.
`onTextLayout: ((TextLayoutResult) -> Unit)? = null`	Callback that is executed when a new text layout is calculated. A `TextLayoutResult` object that callback provides contains paragraph information, size of the text, baselines and other details. The callback can be used to add additional decoration or functionality to the text. For example, to draw selection around the text.
`overflow: TextOverflow = TextOverflow.Clip`	How visual overflow should be handled.
`softWrap: Boolean = true`	Whether the text should break at soft line breaks. If false, the glyphs in the text will be positioned as if there was unlimited horizontal space. If `softWrap` is false, `overflow` and TextAlign may have unexpected effects.
`maxLines: Int = Int.MAX_VALUE`	An optional maximum number of lines for the text to span, wrapping if necessary. If the text exceeds the given number of lines, it will be truncated according to `overflow` and `softWrap`. It is required that 1 <= `minLines`<= `maxLines`.
`minLines: Int = 1`	The minimum height in terms of minimum number of visible lines. It is required that 1 <= `minLines`<= `maxLines`.
`color: ColorProducer? = null`	Overrides the text color provided in `style`
`autoSize: TextAutoSize? = null`	Enable auto sizing for this text composable. Finds the biggest font size that fits in the available space and lays the text out with this size. This performs multiple layout passes and can be slower than using a fixed font size. This takes precedence over sizes defined through `style`. See `TextAutoSize` and androidx.compose.foundation.samples.TextAutoSizeBasicTextSample.

BasicText

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

@Composable
fun BasicText(
    text: AnnotatedString,
    modifier: Modifier = Modifier,
    style: TextStyle = TextStyle.Default,
    onTextLayout: ((TextLayoutResult) -> Unit)? = null,
    overflow: TextOverflow = TextOverflow.Clip,
    softWrap: Boolean = true,
    maxLines: Int = Int.MAX_VALUE,
    minLines: Int = 1,
    inlineContent: Map<String, InlineTextContent> = mapOf(),
    color: ColorProducer? = null,
    autoSize: TextAutoSize? = null
): Unit

Parameters
`text: AnnotatedString`	The text to be displayed.
`modifier: Modifier = Modifier`	`Modifier` to apply to this layout node.
`style: TextStyle = TextStyle.Default`	Style configuration for the text such as color, font, line height etc.
`onTextLayout: ((TextLayoutResult) -> Unit)? = null`	Callback that is executed when a new text layout is calculated. A `TextLayoutResult` object that callback provides contains paragraph information, size of the text, baselines and other details. The callback can be used to add additional decoration or functionality to the text. For example, to draw selection around the text.
`overflow: TextOverflow = TextOverflow.Clip`	How visual overflow should be handled.
`softWrap: Boolean = true`	Whether the text should break at soft line breaks. If false, the glyphs in the text will be positioned as if there was unlimited horizontal space. If `softWrap` is false, `overflow` and TextAlign may have unexpected effects.
`maxLines: Int = Int.MAX_VALUE`	An optional maximum number of lines for the text to span, wrapping if necessary. If the text exceeds the given number of lines, it will be truncated according to `overflow` and `softWrap`. It is required that 1 <= `minLines`<= `maxLines`.
`minLines: Int = 1`	The minimum height in terms of minimum number of visible lines. It is required that 1 <= `minLines`<= `maxLines`.
`inlineContent: Map<String, InlineTextContent> = mapOf()`	A map store composables that replaces certain ranges of the text. It's used to insert composables into text layout. Check `InlineTextContent` for more information.
`color: ColorProducer? = null`	Overrides the text color provided in `style`
`autoSize: TextAutoSize? = null`	Enable auto sizing for this text composable. Finds the biggest font size that fits in the available space and lays the text out with this size. This performs multiple layout passes and can be slower than using a fixed font size. This takes precedence over sizes defined through `style`. See `TextAutoSize` and androidx.compose.foundation.samples.TextAutoSizeBasicTextSample.

BasicTextField

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

Added in 1.7.0

@Composable
fun BasicTextField(
    state: TextFieldState,
    modifier: Modifier = Modifier,
    enabled: Boolean = true,
    readOnly: Boolean = false,
    inputTransformation: InputTransformation? = null,
    textStyle: TextStyle = TextStyle.Default,
    keyboardOptions: KeyboardOptions = KeyboardOptions.Default,
    onKeyboardAction: KeyboardActionHandler? = null,
    lineLimits: TextFieldLineLimits = TextFieldLineLimits.Default,
    onTextLayout: (Density.(getResult: () -> TextLayoutResult?) -> Unit)? = null,
    interactionSource: MutableInteractionSource? = null,
    cursorBrush: Brush = BasicTextFieldDefaults.CursorBrush,
    outputTransformation: OutputTransformation? = null,
    decorator: TextFieldDecorator? = null,
    scrollState: ScrollState = rememberScrollState()
): Unit

Basic text composable that provides an interactive box that accepts text input through software or hardware keyboard, but provides no decorations like hint or placeholder.

All the editing state of this composable is hoisted through state. Whenever the contents of this composable change via user input or semantics, TextFieldState.text gets updated. Similarly, all the programmatic updates made to state also reflect on this composable.

If you want to add decorations to your text field, such as icon or similar, and increase the hit target area, use the decorator.

In order to filter (e.g. only allow digits, limit the number of characters), or change (e.g. convert every character to uppercase) the input received from the user, use an InputTransformation.

Limiting the height of the BasicTextField in terms of line count and choosing a scroll direction can be achieved by using TextFieldLineLimits.

Scroll state of the composable is also hoisted to enable observation and manipulation of the scroll behavior by the developer, e.g. bringing a searched keyword into view by scrolling to its position without focusing, or changing selection.

It's also possible to internally wrap around an existing TextFieldState and expose a more lightweight state hoisting mechanism through a value that dictates the content of the TextField and an onValueChange callback that communicates the changes to this value.

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.BasicTextField
import androidx.compose.foundation.text.input.TextFieldState
import androidx.compose.foundation.text.input.rememberTextFieldState
import androidx.compose.material.Icon
import androidx.compose.material.Text
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.MailOutline
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp

// Demonstrates how to use the decorator API on BasicTextField
val state = rememberTextFieldState("Hello, World!")
BasicTextField(
    state = state,
    decorator = { innerTextField ->
        // Because the decorator is used, the whole Row gets the same behaviour as the internal
        // input field would have otherwise. For example, there is no need to add a
        // `Modifier.clickable` to the Row anymore to bring the text field into focus when user
        // taps on a larger text field area which includes paddings and the icon areas.
        Row(
            Modifier.background(Color.LightGray, RoundedCornerShape(percent = 30))
                .padding(16.dp)
        ) {
            Icon(Icons.Default.MailOutline, contentDescription = "Mail Icon")
            Spacer(Modifier.width(16.dp))
            innerTextField()
        }
    },
)

import androidx.compose.foundation.text.BasicTextField
import androidx.compose.foundation.text.input.InputTransformation
import androidx.compose.foundation.text.input.TextFieldState
import androidx.compose.foundation.text.input.delete
import androidx.compose.foundation.text.input.insert
import androidx.compose.material.Text
import androidx.compose.runtime.remember

// Demonstrates how to create a custom and relatively complex InputTransformation.
val state = remember { TextFieldState() }
BasicTextField(
    state,
    inputTransformation =
        InputTransformation {
            // A filter that always places newly-input text at the start of the string, after a
            // prompt character, like a shell.
            val promptChar = '>'

            fun CharSequence.countPrefix(char: Char): Int {
                var i = 0
                while (i < length && get(i) == char) i++
                return i
            }

            // Step one: Figure out the insertion point.
            val newPromptChars = asCharSequence().countPrefix(promptChar)
            val insertionPoint = if (newPromptChars == 0) 0 else 1

            // Step two: Ensure text is placed at the insertion point.
            if (changes.changeCount == 1) {
                val insertedRange = changes.getRange(0)
                val replacedRange = changes.getOriginalRange(0)
                if (!replacedRange.collapsed && insertedRange.collapsed) {
                    // Text was deleted, delete forwards from insertion point.
                    delete(insertionPoint, insertionPoint + replacedRange.length)
                }
            }
            // Else text was replaced or there were multiple changes - don't handle.

            // Step three: Ensure the prompt character is there.
            if (newPromptChars == 0) {
                insert(0, ">")
            }

            // Step four: Ensure the cursor is ready for the next input.
            placeCursorAfterCharAt(0)
        },
)

import androidx.compose.foundation.text.BasicTextField
import androidx.compose.foundation.text.input.TextFieldState
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember

var text by remember { mutableStateOf("") }
// A reference implementation that demonstrates how to create a TextField with the legacy
// state hoisting design around `BasicTextField(TextFieldState)`
StringTextField(value = text, onValueChange = { text = it })

Parameters
`state: TextFieldState`	`TextFieldState` object that holds the internal editing state of `BasicTextField`.
`modifier: Modifier = Modifier`	optional `Modifier` for this text field.
`enabled: Boolean = true`	controls the enabled state of the `BasicTextField`. When `false`, the text field will be neither editable nor focusable, the input of the text field will not be selectable.
`readOnly: Boolean = false`	controls the editable state of the `BasicTextField`. When `true`, the text field can not be modified, however, a user can focus it and copy text from it. Read-only text fields are usually used to display pre-filled forms that user can not edit.
`inputTransformation: InputTransformation? = null`	Optional `InputTransformation` that will be used to transform changes to the `TextFieldState` made by the user. The transformation will be applied to changes made by hardware and software keyboard events, pasting or dropping text, accessibility services, and tests. The transformation will not be applied when changing the `state` programmatically, or when the transformation is changed. If the transformation is changed on an existing text field, it will be applied to the next user edit. the transformation will not immediately affect the current `state`.
`textStyle: TextStyle = TextStyle.Default`	Typographic and graphic style configuration for text content that's displayed in the editor.
`keyboardOptions: KeyboardOptions = KeyboardOptions.Default`	Software keyboard options that contain configurations such as `KeyboardType` and `ImeAction`.
`onKeyboardAction: KeyboardActionHandler? = null`	Called when the user presses the action button in the input method editor (IME), or by pressing the enter key on a hardware keyboard if the `lineLimits` is configured as `TextFieldLineLimits.SingleLine`. By default this parameter is null, and would execute the default behavior for a received IME Action e.g., `ImeAction.Done` would close the keyboard, `ImeAction.Next` would switch the focus to the next focusable item on the screen.
`lineLimits: TextFieldLineLimits = TextFieldLineLimits.Default`	Whether the text field should be `SingleLine`, scroll horizontally, and ignore newlines; or `MultiLine` and grow and scroll vertically. If `SingleLine` is passed, all newline characters ('\n') within the text will be replaced with regular whitespace (' '), ensuring that the contents of the text field are presented in a single line.
`onTextLayout: (Density.(getResult: () -> TextLayoutResult?) -> Unit)? = null`	Callback that is executed when the text layout becomes queryable. The callback receives a function that returns a `TextLayoutResult` if the layout can be calculated, or null if it cannot. The function reads the layout result from a snapshot state object, and will invalidate its caller when the layout result changes. A `TextLayoutResult` object contains paragraph information, size of the text, baselines and other details. The callback can be used to add additional decoration or functionality to the text. For example, to draw a cursor or selection around the text. `Density` scope is the one that was used while creating the given text layout.
`interactionSource: MutableInteractionSource? = null`	the `MutableInteractionSource` representing the stream of `Interaction`s for this TextField. You can create and pass in your own remembered `MutableInteractionSource` if you want to observe `Interaction`s and customize the appearance / behavior of this TextField for different `Interaction`s.
`cursorBrush: Brush = BasicTextFieldDefaults.CursorBrush`	`Brush` to paint cursor with. If `SolidColor` with `Color.Unspecified` provided, then no cursor will be drawn.
`outputTransformation: OutputTransformation? = null`	An `OutputTransformation` that transforms how the contents of the text field are presented.
`decorator: TextFieldDecorator? = null`	Allows to add decorations around text field, such as icon, placeholder, helper messages or similar, and automatically increase the hit target area of the text field.
`scrollState: ScrollState = rememberScrollState()`	Scroll state that manages either horizontal or vertical scroll of TextField. If `lineLimits` is `SingleLine`, this text field is treated as single line with horizontal scroll behavior. In other cases the text field becomes vertically scrollable.

BasicTextField

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

Added in 1.4.0

@Composable
fun BasicTextField(
    value: String,
    onValueChange: (String) -> Unit,
    modifier: Modifier = Modifier,
    enabled: Boolean = true,
    readOnly: Boolean = false,
    textStyle: TextStyle = TextStyle.Default,
    keyboardOptions: KeyboardOptions = KeyboardOptions.Default,
    keyboardActions: KeyboardActions = KeyboardActions.Default,
    singleLine: Boolean = false,
    maxLines: Int = if (singleLine) 1 else Int.MAX_VALUE,
    minLines: Int = 1,
    visualTransformation: VisualTransformation = VisualTransformation.None,
    onTextLayout: (TextLayoutResult) -> Unit = {},
    interactionSource: MutableInteractionSource? = null,
    cursorBrush: Brush = SolidColor(Color.Black),
    decorationBox: @Composable (@Composable innerTextField: () -> Unit) -> Unit = @Composable { innerTextField -> innerTextField() }
): Unit

Basic composable that enables users to edit text via hardware or software keyboard, but provides no decorations like hint or placeholder.

Whenever the user edits the text, onValueChange is called with the most up to date state represented by String with which developer is expected to update their state.

Unlike TextFieldValue overload, this composable does not let the developer control selection, cursor and text composition information. Please check TextFieldValue and corresponding BasicTextField overload for more information.

It is crucial that the value provided to the onValueChange is fed back into BasicTextField in order to actually display and continue to edit that text in the field. The value you feed back into the field may be different than the one provided to the onValueChange callback, however the following caveats apply:

The new value must be provided to BasicTextField immediately (i.e. by the next frame), or the text field may appear to glitch, e.g. the cursor may jump around. For more information about this requirement, see this article.
The value fed back into the field may be different from the one passed to onValueChange, although this may result in the input connection being restarted, which can make the keyboard flicker for the user. This is acceptable when you're using the callback to, for example, filter out certain types of input, but should probably not be done on every update when entering freeform text.

This composable provides basic text editing functionality, however does not include any decorations such as borders, hints/placeholder. A design system based implementation such as Material Design Filled text field is typically what is needed to cover most of the needs. This composable is designed to be used when a custom implementation for different design system is needed.

Example usage:

import androidx.compose.foundation.text.BasicTextField
import androidx.compose.material.Text
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.saveable.rememberSaveable

var value by rememberSaveable { mutableStateOf("initial value") }
BasicTextField(
    value = value,
    onValueChange = {
        // it is crucial that the update is fed back into BasicTextField in order to
        // see updates on the text
        value = it
    },
)

For example, if you need to include a placeholder in your TextField, you can write a composable using the decoration box like this:

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.text.BasicTextField
import androidx.compose.material.Text
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.saveable.rememberSaveable

var value by rememberSaveable { mutableStateOf("initial value") }
Box {
    BasicTextField(value = value, onValueChange = { value = it })
    if (value.isEmpty()) {
        Text(text = "Placeholder")
    }
}

If you want to add decorations to your text field, such as icon or similar, and increase the hit target area, use the decoration box:

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.BasicTextField
import androidx.compose.material.Icon
import androidx.compose.material.Text
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.MailOutline
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp

var value by rememberSaveable { mutableStateOf("initial value") }
BasicTextField(
    value = value,
    onValueChange = { value = it },
    decorationBox = { innerTextField ->
        // Because the decorationBox is used, the whole Row gets the same behaviour as the
        // internal input field would have otherwise. For example, there is no need to add a
        // Modifier.clickable to the Row anymore to bring the text field into focus when user
        // taps on a larger text field area which includes paddings and the icon areas.
        Row(
            Modifier.background(Color.LightGray, RoundedCornerShape(percent = 30))
                .padding(16.dp)
        ) {
            Icon(Icons.Default.MailOutline, contentDescription = null)
            Spacer(Modifier.width(16.dp))
            innerTextField()
        }
    },
)

In order to create formatted text field, for example for entering a phone number or a social security number, use a visualTransformation parameter. Below is the example of the text field for entering a credit card number:

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.layout.wrapContentSize
import androidx.compose.foundation.text.BasicTextField
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material.Text
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.AnnotatedString
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.text.input.OffsetMapping
import androidx.compose.ui.text.input.TransformedText
import androidx.compose.ui.text.input.VisualTransformation
import androidx.compose.ui.text.substring
import androidx.compose.ui.unit.dp

/** The offset translator used for credit card input field */
val creditCardOffsetTranslator =
    object : OffsetMapping {
        override fun originalToTransformed(offset: Int): Int {
            return when {
                offset < 4 -> offset
                offset < 8 -> offset + 1
                offset < 12 -> offset + 2
                offset <= 16 -> offset + 3
                else -> 19
            }
        }

        override fun transformedToOriginal(offset: Int): Int {
            return when {
                offset <= 4 -> offset
                offset <= 9 -> offset - 1
                offset <= 14 -> offset - 2
                offset <= 19 -> offset - 3
                else -> 16
            }
        }
    }

/**
 * Converts up to 16 digits to hyphen connected 4 digits string. For example, "1234567890123456"
 * will be shown as "1234-5678-9012-3456"
 */
val creditCardTransformation = VisualTransformation { text ->
    val trimmedText = if (text.text.length > 16) text.text.substring(0..15) else text.text
    var transformedText = ""
    trimmedText.forEachIndexed { index, char ->
        transformedText += char
        if ((index + 1) % 4 == 0 && index != 15) transformedText += "-"
    }
    TransformedText(AnnotatedString(transformedText), creditCardOffsetTranslator)
}

var text by rememberSaveable { mutableStateOf("") }
BasicTextField(
    value = text,
    onValueChange = { input ->
        if (input.length <= 16 && input.none { !it.isDigit() }) {
            text = input
        }
    },
    modifier = Modifier.size(170.dp, 30.dp).background(Color.LightGray).wrapContentSize(),
    singleLine = true,
    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
    visualTransformation = creditCardTransformation,
)

Note: This overload does not support KeyboardOptions.showKeyboardOnFocus.

Parameters
`value: String`	the input `String` text to be shown in the text field
`onValueChange: (String) -> Unit`	the callback that is triggered when the input service updates the text. An updated text comes as a parameter of the callback
`modifier: Modifier = Modifier`	optional `Modifier` for this text field.
`enabled: Boolean = true`	controls the enabled state of the `BasicTextField`. When `false`, the text field will be neither editable nor focusable, the input of the text field will not be selectable
`readOnly: Boolean = false`	controls the editable state of the `BasicTextField`. When `true`, the text field can not be modified, however, a user can focus it and copy text from it. Read-only text fields are usually used to display pre-filled forms that user can not edit
`textStyle: TextStyle = TextStyle.Default`	Style configuration that applies at character level such as color, font etc.
`keyboardOptions: KeyboardOptions = KeyboardOptions.Default`	software keyboard options that contains configuration such as `KeyboardType` and `ImeAction`.
`keyboardActions: KeyboardActions = KeyboardActions.Default`	when the input service emits an IME action, the corresponding callback is called. Note that this IME action may be different from what you specified in `KeyboardOptions.imeAction`.
`singleLine: Boolean = false`	when set to true, this text field becomes a single horizontally scrolling text field instead of wrapping onto multiple lines. The keyboard will be informed to not show the return key as the `ImeAction`. `maxLines` and `minLines` are ignored as both are automatically set to 1.
`maxLines: Int = if (singleLine) 1 else Int.MAX_VALUE`	the maximum height in terms of maximum number of visible lines. It is required that 1 <= `minLines`<= `maxLines`. This parameter is ignored when `singleLine` is true.
`minLines: Int = 1`	the minimum height in terms of minimum number of visible lines. It is required that 1 <= `minLines`<= `maxLines`. This parameter is ignored when `singleLine` is true.
`visualTransformation: VisualTransformation = VisualTransformation.None`	The visual transformation filter for changing the visual representation of the input. By default no visual transformation is applied.
`onTextLayout: (TextLayoutResult) -> Unit = {}`	Callback that is executed when a new text layout is calculated. A `TextLayoutResult` object that callback provides contains paragraph information, size of the text, baselines and other details. The callback can be used to add additional decoration or functionality to the text. For example, to draw a cursor or selection around the text.
`interactionSource: MutableInteractionSource? = null`	an optional hoisted `MutableInteractionSource` for observing and emitting `Interaction`s for this text field. You can use this to change the text field's appearance or preview the text field in different states. Note that if `null` is provided, interactions will still happen internally.
`cursorBrush: Brush = SolidColor(Color.Black)`	`Brush` to paint cursor with. If `SolidColor` with `Color.Unspecified` provided, there will be no cursor drawn
`decorationBox: @Composable (@Composable innerTextField: () -> Unit) -> Unit = @Composable { innerTextField -> innerTextField() }`	Composable lambda that allows to add decorations around text field, such as icon, placeholder, helper messages or similar, and automatically increase the hit target area of the text field. To allow you to control the placement of the inner text field relative to your decorations, the text field implementation will pass in a framework-controlled composable parameter "innerTextField" to the decorationBox lambda you provide. You must call innerTextField exactly once.

BasicTextField

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

Added in 1.4.0

@Composable
fun BasicTextField(
    value: TextFieldValue,
    onValueChange: (TextFieldValue) -> Unit,
    modifier: Modifier = Modifier,
    enabled: Boolean = true,
    readOnly: Boolean = false,
    textStyle: TextStyle = TextStyle.Default,
    keyboardOptions: KeyboardOptions = KeyboardOptions.Default,
    keyboardActions: KeyboardActions = KeyboardActions.Default,
    singleLine: Boolean = false,
    maxLines: Int = if (singleLine) 1 else Int.MAX_VALUE,
    minLines: Int = 1,
    visualTransformation: VisualTransformation = VisualTransformation.None,
    onTextLayout: (TextLayoutResult) -> Unit = {},
    interactionSource: MutableInteractionSource? = null,
    cursorBrush: Brush = SolidColor(Color.Black),
    decorationBox: @Composable (@Composable innerTextField: () -> Unit) -> Unit = @Composable { innerTextField -> innerTextField() }
): Unit

Basic composable that enables users to edit text via hardware or software keyboard, but provides no decorations like hint or placeholder.

Whenever the user edits the text, onValueChange is called with the most up to date state represented by TextFieldValue. TextFieldValue contains the text entered by user, as well as selection, cursor and text composition information. Please check TextFieldValue for the description of its contents.

The new value must be provided to BasicTextField immediately (i.e. by the next frame), or the text field may appear to glitch, e.g. the cursor may jump around. For more information about this requirement, see this article.
The value fed back into the field may be different from the one passed to onValueChange, although this may result in the input connection being restarted, which can make the keyboard flicker for the user. This is acceptable when you're using the callback to, for example, filter out certain types of input, but should probably not be done on every update when entering freeform text.

Example usage:

import androidx.compose.foundation.text.BasicTextField
import androidx.compose.material.Text
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.compose.ui.text.input.TextFieldValue

var value by
    rememberSaveable(stateSaver = TextFieldValue.Saver) { mutableStateOf(TextFieldValue()) }
BasicTextField(
    value = value,
    onValueChange = {
        // it is crucial that the update is fed back into BasicTextField in order to
        // see updates on the text
        value = it
    },
)

For example, if you need to include a placeholder in your TextField, you can write a composable using the decoration box like this:

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.text.BasicTextField
import androidx.compose.material.Text
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.saveable.rememberSaveable

var value by rememberSaveable { mutableStateOf("initial value") }
Box {
    BasicTextField(value = value, onValueChange = { value = it })
    if (value.isEmpty()) {
        Text(text = "Placeholder")
    }
}

If you want to add decorations to your text field, such as icon or similar, and increase the hit target area, use the decoration box:

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.BasicTextField
import androidx.compose.material.Icon
import androidx.compose.material.Text
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.MailOutline
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp

var value by rememberSaveable { mutableStateOf("initial value") }
BasicTextField(
    value = value,
    onValueChange = { value = it },
    decorationBox = { innerTextField ->
        // Because the decorationBox is used, the whole Row gets the same behaviour as the
        // internal input field would have otherwise. For example, there is no need to add a
        // Modifier.clickable to the Row anymore to bring the text field into focus when user
        // taps on a larger text field area which includes paddings and the icon areas.
        Row(
            Modifier.background(Color.LightGray, RoundedCornerShape(percent = 30))
                .padding(16.dp)
        ) {
            Icon(Icons.Default.MailOutline, contentDescription = null)
            Spacer(Modifier.width(16.dp))
            innerTextField()
        }
    },
)

Note: This overload does not support KeyboardOptions.showKeyboardOnFocus.

Parameters
`value: TextFieldValue`	The `androidx.compose.ui.text.input.TextFieldValue` to be shown in the `BasicTextField`.
`onValueChange: (TextFieldValue) -> Unit`	Called when the input service updates the values in `TextFieldValue`.
`modifier: Modifier = Modifier`	optional `Modifier` for this text field.
`enabled: Boolean = true`	controls the enabled state of the `BasicTextField`. When `false`, the text field will be neither editable nor focusable, the input of the text field will not be selectable
`readOnly: Boolean = false`	controls the editable state of the `BasicTextField`. When `true`, the text field can not be modified, however, a user can focus it and copy text from it. Read-only text fields are usually used to display pre-filled forms that user can not edit
`textStyle: TextStyle = TextStyle.Default`	Style configuration that applies at character level such as color, font etc.
`keyboardOptions: KeyboardOptions = KeyboardOptions.Default`	software keyboard options that contains configuration such as `KeyboardType` and `ImeAction`.
`keyboardActions: KeyboardActions = KeyboardActions.Default`	when the input service emits an IME action, the corresponding callback is called. Note that this IME action may be different from what you specified in `KeyboardOptions.imeAction`.
`singleLine: Boolean = false`	when set to true, this text field becomes a single horizontally scrolling text field instead of wrapping onto multiple lines. The keyboard will be informed to not show the return key as the `ImeAction`. `maxLines` and `minLines` are ignored as both are automatically set to 1.
`maxLines: Int = if (singleLine) 1 else Int.MAX_VALUE`	the maximum height in terms of maximum number of visible lines. It is required that 1 <= `minLines`<= `maxLines`. This parameter is ignored when `singleLine` is true.
`minLines: Int = 1`	the minimum height in terms of minimum number of visible lines. It is required that 1 <= `minLines`<= `maxLines`. This parameter is ignored when `singleLine` is true.
`visualTransformation: VisualTransformation = VisualTransformation.None`	The visual transformation filter for changing the visual representation of the input. By default no visual transformation is applied.
`onTextLayout: (TextLayoutResult) -> Unit = {}`	Callback that is executed when a new text layout is calculated. A `TextLayoutResult` object that callback provides contains paragraph information, size of the text, baselines and other details. The callback can be used to add additional decoration or functionality to the text. For example, to draw a cursor or selection around the text.
`interactionSource: MutableInteractionSource? = null`	an optional hoisted `MutableInteractionSource` for observing and emitting `Interaction`s for this text field. You can use this to change the text field's appearance or preview the text field in different states. Note that if `null` is provided, interactions will still happen internally.
`cursorBrush: Brush = SolidColor(Color.Black)`	`Brush` to paint cursor with. If `SolidColor` with `Color.Unspecified` provided, there will be no cursor drawn
`decorationBox: @Composable (@Composable innerTextField: () -> Unit) -> Unit = @Composable { innerTextField -> innerTextField() }`	Composable lambda that allows to add decorations around text field, such as icon, placeholder, helper messages or similar, and automatically increase the hit target area of the text field. To allow you to control the placement of the inner text field relative to your decorations, the text field implementation will pass in a framework-controlled composable parameter "innerTextField" to the decorationBox lambda you provide. You must call innerTextField exactly once.

ClickableText

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

@Composable
fun ClickableText(
    text: AnnotatedString,
    modifier: Modifier = Modifier,
    style: TextStyle = TextStyle.Default,
    softWrap: Boolean = true,
    overflow: TextOverflow = TextOverflow.Clip,
    maxLines: Int = Int.MAX_VALUE,
    onTextLayout: (TextLayoutResult) -> Unit = {},
    onClick: (Int) -> Unit
): Unit

A continent version of BasicText component to be able to handle click event on the text.

This is a shorthand of BasicText with pointerInput to be able to handle click event easily.

import androidx.compose.foundation.text.ClickableText
import androidx.compose.material.Text
import androidx.compose.ui.text.AnnotatedString

ClickableText(
    text = AnnotatedString("Click Me"),
    onClick = { offset -> Log.d("ClickableText", "$offset -th character is clicked.") },
)

For other gestures, e.g. long press, dragging, follow sample code.

import androidx.compose.foundation.gestures.detectTapGestures
import androidx.compose.material.Text
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.input.pointer.pointerInput
import androidx.compose.ui.text.TextLayoutResult

val layoutResult = remember { mutableStateOf<TextLayoutResult?>(null) }
val gesture =
    Modifier.pointerInput(onLongClick) {
        detectTapGestures(
            onLongPress = { pos ->
                layoutResult.value?.let { layout ->
                    onLongClick(layout.getOffsetForPosition(pos))
                }
            }
        )
    }

Text(
    text = text,
    modifier = modifier.then(gesture),
    style = style,
    softWrap = softWrap,
    overflow = overflow,
    maxLines = maxLines,
    onTextLayout = {
        onTextLayout(it)
        layoutResult.value = it
    },
)

Parameters
`text: AnnotatedString`	The text to be displayed.
`modifier: Modifier = Modifier`	Modifier to apply to this layout node.
`style: TextStyle = TextStyle.Default`	Style configuration for the text such as color, font, line height etc.
`softWrap: Boolean = true`	Whether the text should break at soft line breaks. If false, the glyphs in the text will be positioned as if there was unlimited horizontal space. If `softWrap` is false, `overflow` and `TextAlign` may have unexpected effects.
`overflow: TextOverflow = TextOverflow.Clip`	How visual overflow should be handled.
`maxLines: Int = Int.MAX_VALUE`	An optional maximum number of lines for the text to span, wrapping if necessary. If the text exceeds the given number of lines, it will be truncated according to `overflow` and `softWrap`. If it is not null, then it must be greater than zero.
`onTextLayout: (TextLayoutResult) -> Unit = {}`	Callback that is executed when a new text layout is calculated. A `TextLayoutResult` object that callback provides contains paragraph information, size of the text, baselines and other details. The callback can be used to add additional decoration or functionality to the text. For example, to draw selection around the text.
`onClick: (Int) -> Unit`	Callback that is executed when users click the text. This callback is called with clicked character's offset. Note: this composable is now deprecated. Instead, use regular `androidx.compose.material3.Text` or `androidx.compose.foundation.text.BasicText` and pass an AnnotatedString that contains a `androidx.compose.ui.text.LinkAnnotation`.

See also
`BasicText`
`pointerInput`
`detectTapGestures`
`LinkAnnotation`

KeyboardActions

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

Added in 1.0.0

fun KeyboardActions(onAny: KeyboardActionScope.() -> Unit): KeyboardActions

Creates an instance of KeyboardActions that uses the specified lambda for all ImeActions.

Extension functions

appendInlineContent

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

Added in 1.0.0

fun AnnotatedString.Builder.appendInlineContent(
    id: String,
    alternateText: String = REPLACEMENT_CHAR
): Unit

Used to insert composables into the text layout. This method can be used together with the inlineContent parameter of BasicText. It will append the alternateText to this AnnotatedString and also mark this range of text to be replaced by a composable. BasicText will try to find an InlineTextContent in the map defined by inlineContent whose key equals to id, and it will use the InlineTextContent.children to replace this range of text.

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.text.BasicText
import androidx.compose.foundation.text.InlineTextContent
import androidx.compose.foundation.text.appendInlineContent
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.Placeholder
import androidx.compose.ui.text.PlaceholderVerticalAlign
import androidx.compose.ui.text.buildAnnotatedString
import androidx.compose.ui.unit.em

val myId = "inlineContent"
val text = buildAnnotatedString {
    append("Hello")
    // Append a placeholder string "[myBox]" and attach an annotation "inlineContent" on it.
    appendInlineContent(myId, "[myBox]")
}

val inlineContent =
    mapOf(
        Pair(
            // This tells the [BasicText] to replace the placeholder string "[myBox]" by
            // the composable given in the [InlineTextContent] object.
            myId,
            InlineTextContent(
                // Placeholder tells text layout the expected size and vertical alignment of
                // children composable.
                Placeholder(
                    width = 0.5.em,
                    height = 0.5.em,
                    placeholderVerticalAlign = PlaceholderVerticalAlign.AboveBaseline,
                )
            ) {
                // This [Box] will fill maximum size, which is specified by the [Placeholder]
                // above. Notice the width and height in [Placeholder] are specified in
                // TextUnit,
                // and are converted into pixel by text layout.
                Box(modifier = Modifier.fillMaxSize().background(color = Color.Red))
            },
        )
    )

BasicText(text = text, inlineContent = inlineContent)

Parameters
`id: String`	The id used to look up the `InlineTextContent`, it is referred by the inlineContent parameter of `BasicText` to replace the `alternateText` to the corresponding composable.
`alternateText: String = REPLACEMENT_CHAR`	The text to be replaced by the inline content. It's displayed when the inlineContent parameter of `BasicText` doesn't contain `id`. Accessibility features will also use this text to describe the inline content.

Throws
`kotlin.IllegalArgumentException`	if `alternateText` has zero length.

See also
`InlineTextContent`
`BasicText`

Top-level properties

LocalAutofillHighlightBrush

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

Added in 1.10.0

val LocalAutofillHighlightBrush: ProvidableCompositionLocal<Brush>

CompositionLocal used to change the highlight Brush used for autofilled components.

LocalAutofillHighlightColor

Cmn

Artifact: androidx.compose.foundation:foundation

View Source

Added in 1.8.0

Deprecated in 1.10.0

val LocalAutofillHighlightColor: ProvidableCompositionLocal<Color>

CompositionLocal used to change the autofillHighlightColor used by components in the hierarchy.

LocalBackgroundTextMeasurementExecutor

android

Artifact: androidx.compose.foundation:foundation

View Source

val LocalBackgroundTextMeasurementExecutor: ProvidableCompositionLocal<Executor?>

CompositionLocal that provides an Executor for background text processing to potentially get run on.

BasicText premeasure is the process of using a background thread to early start metrics calculation for Text composables on Android to warm up the underlying text layout cache. This becomes especially useful in LazyLists when precomposition may precede premeasurement by at least a frame, which gives the background thread enough time to fully calculate text metrics. This approximately reduces text layout duration on main thread from 50% to 90%.

By default this CompositionLocal provides null, which means that any text prefetch behavior will revert to the system default. You can provide an executor like Executors.newSingleThreadExecutor() for BasicText to schedule background tasks.

Please note that prefetch text does not guarantee a net performance increase. It may actually be harmful in certain scenarios where there is not enough time between composition and measurement for background thread to actually start warming the cache, or when the text is long enough that it floods the cache and overflows it, at around 5000 words.

Use benchmarking tools to check whether enabling this behavior works well for your use case.

import androidx.compose.foundation.text.BasicText
import androidx.compose.foundation.text.LocalBackgroundTextMeasurementExecutor
import androidx.compose.runtime.CompositionLocalProvider

CompositionLocalProvider(
    LocalBackgroundTextMeasurementExecutor provides DefaultTextMeasurementExecutor
) {
    BasicText("Hello World!")
}