Jetpack Compose why is onValueChange getting called over and over?

Question

This code works as expected. The println only prints when the text value changes or the user moves the cursor

val testText = remember { mutableStateOf(TextFieldValue()) }
TextField(
    value = testText.value,
    onValueChange = {
        // should only happen when you type or move cursor
        println("onValueChange called")
        testText.value = it.copy(
            annotatedString = buildAnnotatedString {
                append(it.text)
            },
        )
    },
)

However, some strange things happen when I add a style span:

val testText = remember { mutableStateOf(TextFieldValue()) }
TextField(
    value = testText.value,
    onValueChange = {
        // should only happen when you type or move cursor
        println("onValueChange called")
        testText.value = it.copy(
            annotatedString = buildAnnotatedString {
                withStyle(SpanStyle(Color.Blue)) {
                    append(it.text)
                }
            },
        )
    },
)

As I type, if my cursor is located in a word that begins with a letter, then the println is continuously called. But if my cursor is in a word that doesn't start with a letter, then the println acts normal. For example, if my text looks like @john{cursor here} is a person or john 9{cursor here}9 test then it's normal. But if my text looks like john{cursor here} is a person then I get the continuous prints.

Why is this happening?

Dharman · Accepted Answer · 2025-04-16 16:15:58Z

1

I found out this is happening due to IME auto suggestions. I got this to work by using the TextField visualTransformation parameters instead of applying the style directly to the TextFieldValue.

_{Posted on behalf of the question asker}

answered Apr 16, 2025 at 16:15

community wiki

Dharman

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Comments

Chirag Thummar · Accepted Answer · 2023-07-29 08:45:16Z

0

You doing it the wrong way. if you want to assign value you can do it like below example

val testText = remember { mutableStateOf(TextFieldValue()) }
    TextField(
        value = testText.value.copy(
            annotatedString = buildAnnotatedString {
                withStyle(SpanStyle(Color.Blue)) {
                    append(testText.value.text)
                }
            },
        ),
        onValueChange = {
            // should only happen when you type or move cursor
            println("onValueChange called")
            testText.value = it
        },
    )

I have tested the code in my Android Studio It is working as in Example 1

answered Jul 29, 2023 at 8:45

Chirag Thummar

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1 Comment

Marty Miller Jan 7 at 21:31

"testText.value = it" shouldn't compile since testText is a val

rmtheis · Accepted Answer · 2025-04-16 14:54:00Z

0

You need to provide all three arguments when you copy TextFieldValue -- text (or annotatedString), selection, and composition in order to get acceptable behavior.

edited Apr 16, 2025 at 14:54

answered Apr 16, 2025 at 14:44

rmtheis

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