TextFieldBuffer

fun asCharSequence(): CharSequence

Returns a CharSequence backed by this buffer. Any subsequent changes to this buffer will be visible in the returned sequence as well.

fun charAt(index: Int): Char

Returns the Char at index in this buffer.

fun placeCursorAfterCharAt(index: Int): Unit

Places the cursor after the character at the given index.

If index is inside a surrogate pair or other invalid run, the cursor will be placed at the nearest later index.

To place the cursor at the end of the field, after the last character, pass index TextFieldBuffer.length or call placeCursorAtEnd.

fun placeCursorBeforeCharAt(index: Int): Unit

Places the cursor before the character at the given index.

If index is inside a surrogate pair or other invalid run, the cursor will be placed at the nearest earlier index.

To place the cursor at the beginning of the field, pass index 0. To place the cursor at the end of the field, after the last character, pass index TextFieldBuffer.length or call placeCursorAtEnd.

fun replace(start: Int, end: Int, text: CharSequence): Unit

Replaces the text between start (inclusive) and end (exclusive) in this value with text, and records the change in changes.

fun revertAllChanges(): Unit

Revert all changes made to this value since it was created.

After calling this method, this object will be in the same state it was when it was initially created, and changes will be empty.

@ExperimentalFoundationApi
val changes: TextFieldBuffer.ChangeList

The ChangeList represents the changes made to this value and is inherently mutable. This means that the returned ChangeList always reflects the complete list of changes made to this value at any given time, even those made after reading this property.

import androidx.compose.foundation.text.BasicTextField
import androidx.compose.foundation.text.input.TextFieldState
import androidx.compose.foundation.text.input.forEachChange
import androidx.compose.foundation.text.input.rememberTextFieldState
import androidx.compose.material.Text
import androidx.compose.runtime.remember
import androidx.compose.ui.text.substring

// Print a log message every time the text is changed.
BasicTextField(
    state = rememberTextFieldState(),
    inputTransformation = {
        changes.forEachChange { sourceRange, replacedLength ->
            val newString = asCharSequence().substring(sourceRange)
            println("""$replacedLength characters were replaced with "$newString"""")
        }
    }
)

import androidx.compose.foundation.text.BasicTextField
import androidx.compose.foundation.text.input.TextFieldState
import androidx.compose.foundation.text.input.delete
import androidx.compose.foundation.text.input.forEachChange
import androidx.compose.foundation.text.input.forEachChangeReversed
import androidx.compose.foundation.text.input.insert
import androidx.compose.foundation.text.input.rememberTextFieldState
import androidx.compose.material.Text
import androidx.compose.runtime.remember

// Make a text field behave in "insert mode" – inserted text overwrites the text ahead of it
// instead of being inserted.
BasicTextField(
    state = rememberTextFieldState(),
    inputTransformation = {
        changes.forEachChangeReversed { range, originalRange ->
            if (!range.collapsed && originalRange.collapsed) {
                // New text was inserted, delete the text ahead of it.
                delete(
                    range.end.coerceAtMost(length),
                    (range.end + range.length).coerceAtMost(length)
                )
            }
        }
    }
)

val hasSelection: Boolean

True if the selection range has non-zero length. If this is false, then the selection represents the cursor.

val length: Int

The number of characters in the text field.

val originalSelection: TextRange

Original selection before the changes. Calling revertAllChanges will set the selection to this value.

val originalText: CharSequence

Original text content of the buffer before any changes were applied. Calling revertAllChanges will set the contents of this buffer to this value.

var selection: TextRange

The selected range of characters.

Places the selection around the given range in characters.

If the start or end of TextRange fall inside surrogate pairs or other invalid runs, the values will be adjusted to the nearest earlier and later characters, respectively.

To place the start of the selection at the beginning of the field, set this value to TextRange.Zero. To place the end of the selection at the end of the field, after the last character, pass TextFieldBuffer.length. Passing a zero-length range is the same as calling placeCursorBeforeCharAt.

fun TextFieldBuffer.delete(start: Int, end: Int): Unit

Delete the text between start (inclusive) and end (exclusive). Pass 0 as start and TextFieldBuffer.length as end to delete everything in this buffer.

fun TextFieldBuffer.insert(index: Int, text: String): Unit

Insert text at the given index in this value. Pass 0 to insert text at the beginning of this buffer, and pass TextFieldBuffer.length to insert text at the end of this buffer.

This is equivalent to calling replace(index, index, text).

fun TextFieldBuffer.placeCursorAtEnd(): Unit

Places the cursor at the end of the text.

fun TextFieldBuffer.selectAll(): Unit

Places the selection around all the text.