如果我已经清楚地理解了这个问题，正如@Gabriele Mariotti建议的那样，您可以存储文本字段的先前值，然后在单击按钮时将其与文本字段本身中的实际值进行比较。
可以使用Composable函数来安排代码，如下所示：

@Composable
fun SaveButton(
    modifier: Modifier = Modifier
) {
    var currentValue by remember { mutableStateOf("") }
    var previousValue by remember { mutableStateOf(currentValue) }
    val context = LocalContext.current

    Row(
        verticalAlignment = Alignment.CenterVertically,
        horizontalArrangement = Arrangement.SpaceEvenly,
        modifier = Modifier.fillMaxSize()
    ) {
        OutlinedTextField(
            value = currentValue,
            modifier = modifier,
            onValueChange = {
                currentValue = it
            }
        )

        Button(onClick = {
            if (currentValue != previousValue) {
                Toast.makeText(context, "API request started", Toast.LENGTH_SHORT).show()
                previousValue = currentValue
                // Handle API request
            } else {
                Toast.makeText(context, "The text has not changed. Returning to the previous screen...", Toast.LENGTH_LONG).show()
                // Handle on back screen
            }
        }) {
            Text(text = "Save")
        }
    }
}