根据文本状态，可以为trailingIcon参数指定null或实际视图：

var text by remember { mutableStateOf("") }
val trailingIconView = @Composable {
    IconButton(
        onClick = {
            text = ""
        },
    ) {
        Icon(
            Icons.Default.Clear,
            contentDescription = "",
            tint = Color.Black
        )
    }
}
TextField(
    value = text,
    onValueChange = { text = it },
    trailingIcon = if (text.isNotBlank()) trailingIconView else null,
)

您可以添加条件以使trailingIcon可见。
例如：

var text by remember { mutableStateOf("") }
val isVisible by remember {
    derivedStateOf {
        text.isNotBlank()
    }
}

OutlinedTextField(
    value = text,
    onValueChange = {
        text = it
    },
    trailingIcon = {
        if (isVisible) {
            IconButton(
                onClick = { text = "" }
            ) {
                Icon(
                    imageVector = Icons.Default.Clear,
                    contentDescription = "Clear"
                )
            }
        }
    }
)