Exposed drop-down menu for jetpack compose

The M2 (starting from the version 1.1.0-alpha06) and M3 have the implementation of ExposedDropdownMenu based on ExposedDropdownMenuBox with TextField and DropdownMenu inside.

Something like:

    val options = listOf("Option 1", "Option 2", "Option 3", "Option 4", "Option 5")
    var expanded by remember { mutableStateOf(false) }
    var selectedOptionText by remember { mutableStateOf(options[0]) }
    
    ExposedDropdownMenuBox(
        expanded = expanded,
        onExpandedChange = {
            expanded = !expanded
        }
    ) {
        TextField(
            readOnly = true,
            value = selectedOptionText,
            onValueChange = { },
            label = { Text("Label") },
            trailingIcon = {
                ExposedDropdownMenuDefaults.TrailingIcon(
                    expanded = expanded
                )
            },
            colors = ExposedDropdownMenuDefaults.textFieldColors()
        )
        ExposedDropdownMenu(
            expanded = expanded,
            onDismissRequest = {
                expanded = false
            }
        ) {
            options.forEach { selectionOption ->
                DropdownMenuItem(
                    onClick = {
                        selectedOptionText = selectionOption
                        expanded = false
                    }
                ){
                    Text(text = selectionOption) 
                }
            }
        }
    }

If you are using M3 (androidx.compose.material3) you have also to pass the menuAnchor modifier to the TextField:

ExposedDropdownMenuBox(
    expanded = expanded,
    onExpandedChange = { expanded = !expanded },
) {
   TextField(
        //...
        modifier = Modifier.menuAnchor()
    )
    ExposedDropdownMenu(){ /*..  */ }
}

Also in M3 in the DropdownMenuItem you have to move the content in the text parameter:

DropdownMenuItem(
    text = { Text(text = selectionOption) },
    onClick = {
        selectedOptionText = selectionOption
        expanded = false
    }
)

---

With the M2 version 1.0.x there isn’t a built-in component.
You can use a OutlinedTextField + DropdownMenu. It is important to wrap the them in a Box. In this way the TextField will be used as the ‘anchor’.

It is just a basic (very basic) implementation:

var expanded by remember { mutableStateOf(false) }
val suggestions = listOf("Item1","Item2","Item3")
var selectedText by remember { mutableStateOf("") }

var textfieldSize by remember { mutableStateOf(Size.Zero)}

val icon = if (expanded)
    Icons.Filled.ArrowDropUp //it requires androidx.compose.material:material-icons-extended
else
    Icons.Filled.ArrowDropDown


Box() {
    OutlinedTextField(
        value = selectedText,
        onValueChange = { selectedText = it },
        modifier = Modifier
            .fillMaxWidth()
            .onGloballyPositioned { coordinates ->
                //This value is used to assign to the DropDown the same width
                textfieldSize = coordinates.size.toSize()
            },
        label = {Text("Label")},
        trailingIcon = {
            Icon(icon,"contentDescription",
                 Modifier.clickable { expanded = !expanded })
        }
    )
    DropdownMenu(
        expanded = expanded,
        onDismissRequest = { expanded = false },
        modifier = Modifier
            .width(with(LocalDensity.current){textfieldSize.width.toDp()})
    ) {
        suggestions.forEach { label ->
            DropdownMenuItem(onClick = {
                selectedText = label
            }) {
                Text(text = label)
            }
        }
    }
}