我想在选择新位置时重置该值并将其设置为空字符串
我尝试像这样重置值：
**tower.value = ""
floorNumber.value = ""**
但在 UI 方面，价值仍然存在
**这是下拉菜单 **
@Composable
fun DropDownBox(
items:List<String>,
onItemSelected: (String) -> Unit,
textFieldLabel:String,
modifier: Modifier = Modifier,
) {
var expanded by remember { mutableStateOf(false) }
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
Log.d("select", "$selectedText")
Column() {
OutlinedTextField(
textStyle = TextStyle(
fontFamily = mont,
color = Color.Black),
shape = RoundedCornerShape(15.dp),
value = selectedText,
onValueChange = {
selectedText = it },
modifier = Modifier
.fillMaxWidth()
.onGloballyPositioned { coordinates ->
//This value is used to assign to the DropDown the same width
textfieldSize = coordinates.size.toSize()
},
label ={ Text(textFieldLabel,
fontSize = 15.sp,
fontWeight = FontWeight.Normal,
fontFamily = mont
)
},
trailingIcon = {
Icon(icon,"contentDescription",
Modifier.clickable { expanded = !expanded })
},
readOnly = true,
)
DropdownMenu(
expanded = expanded,
onDismissRequest = { expanded = false },
modifier = Modifier
.width(with(LocalDensity.current){textfieldSize.width.toDp()})
) {
items.sorted().forEach { label ->
DropdownMenuItem(onClick = {
selectedText = label
onItemSelected(selectedText)
expanded = false
}) {
Text(text = label,
fontSize = 15.sp,
fontWeight = FontWeight.Normal,
fontFamily = mont
)
}
}
}
}
}
我有一个下拉菜单，可显示位置、塔楼和楼层号。我希望如果我选择一个新位置，塔楼和楼层号的值将重置为空字符串。我已经尝试过这段代码，但唯一的变化是值而不是 UI 本身。所以我正在尝试调试这段代码，请帮助我解决我的代码
var isLocationSelected by remember { mutableStateOf(false) }
var isTowerSelected by remember { mutableStateOf(false) }
var isFloorSelected by remember { mutableStateOf(false) }
Log.d("LOCATION", "$location")
DropdownTextField(
items = locationsMap.map {
it.key
},
onItemSelected = {
if (locationErrorState.value) {
locationErrorState.value = false
}
location.value = it
isLocationSelected = true
isTowerSelected = false
isFloorSelected = false
tower.value = ""
floorNumber.value = ""
unitNumber.value = ""
unitNumberSuffx.value = ""
/* Populate towers dropdown list */
var towersList:MutableList<String> = ArrayList()
towers.value = towersList
var suffixList:MutableList<String> = ArrayList()
suffix.value = suffixList
val building = locationsMap[location.value]
building?.let {
it.map {
it.towerName?.let {
towersList.add(it)
}
it.unitNumberSuffix.let {
it?.let {
it.map {
suffixList.add(it)
}
}
}
}
}
if (!towersList.isEmpty()) {
towers.value = towersList
} else {
building?.let {
val maxFloorNumber = it.first().floorNumber
val maxUnit = it.first().unitsPerFloor
var unitList: MutableList<String> = ArrayList()
var floorsList: MutableList<String> = ArrayList()
for (n in 1..maxFloorNumber.toInt()) {
floorsList.add(n.toString())
}
for (n in 1..maxUnit) {
// Add "0" in the middle for unit numbers 1-9
val formattedUnit = if (n in 1..9) "0$n" else n.toString()
unitList.add(formattedUnit)
}
unitNumbers.value = unitList
floors.value = floorsList
}
}
if (!suffixList.isEmpty()) {
suffix.value = suffixList.distinct()
}
},
textFieldLabel = "Location",
)
Log.d("TOWER", "$tower")
if (isLocationSelected && towers.value.count() >= 1) {
Spacer(modifier = Modifier.height(8.dp))
DropdownTextField(items = towers.value,
onItemSelected = {
if (towerErrorState.value) {
towerErrorState.value = true
}
tower.value = it
isTowerSelected = true
isFloorSelected = false
floorNumber.value = ""
/*
Update floors
*/
val building = locationsMap[location.value]
building?.let {
it.map {
if (it.towerName == tower.value) {
val maxFloorNumber = it.floorNumber
val maxUnit = it.unitsPerFloor
var unitList:MutableList<String> = ArrayList()
var floorsList:MutableList<String> = ArrayList()
for(n in 1..maxFloorNumber.toInt()) {
floorsList.add(n.toString())
}
for (n in 1..maxUnit) {
// Add "0" in the middle for unit numbers 1-9
val formattedUnit = if (n in 1..9) "0$n" else n.toString()
unitList.add(formattedUnit)
}
unitNumbers.value = unitList
floors.value = floorsList
}
}
}
},
textFieldLabel = "Tower",
)
}
Spacer(modifier = Modifier.height(8.dp))
Log.d("FLOOR", "$floorNumber")
if (isLocationSelected || isTowerSelected) {
DropDownBox(
items = floors.value,
onItemSelected = {
if (floorNumberErrorState.value) {
floorNumberErrorState.value = false
}
Log.d("TEST", "$it")
floorNumber.value = it
isFloorSelected = true
unitNumber.value = ""
},
textFieldLabel = stringResource(R.string.FloorNumber),
)
}
为了确保在选择新位置时重置 DropDownBox 值，您可以添加逻辑以重置 DropDownBox 可组合项本身中的选定值。下面是 DropDownBox 可组合项的修改版本，添加了在选择新位置时重置所选文本的逻辑：
@Composable
fun DropDownBox(
items: List<String>,
onItemSelected: (String) -> Unit,
textFieldLabel: String,
modifier: Modifier = Modifier,
) {
var expanded by remember { mutableStateOf(false) }
var selectedText by remember { mutableStateOf("") }
var textfieldSize by remember { mutableStateOf(Size.Zero) }
val icon = if (expanded)
Icons.Filled.ArrowDropUp
else
Icons.Filled.ArrowDropDown
Column {
OutlinedTextField(
value = selectedText,
onValueChange = {
selectedText = it
},
modifier = Modifier
.fillMaxWidth()
.onGloballyPositioned { coordinates ->
textfieldSize = coordinates.size.toSize()
},
label = {
Text(textFieldLabel)
},
trailingIcon = {
Icon(icon, contentDescription = "Dropdown Icon",
modifier = Modifier.clickable { expanded = !expanded })
},
readOnly = true,
)
DropdownMenu(
expanded = expanded,
onDismissRequest = { expanded = false },
modifier = Modifier.width(with(LocalDensity.current) {
textfieldSize.width.toDp()
})
) {
items.sorted().forEach { label ->
DropdownMenuItem(onClick = {
selectedText = label
onItemSelected(selectedText)
expanded = false
}) {
Text(text = label)
}
}
}
}
// Reset selected text when a new location is selected
DisposableEffect(Unit) {
onDispose {
selectedText = ""
}
}
}
通过此修改，每当选择新位置时，DropDownBox 中的 selectedText 状态变量将重置为空字符串，从而有效地清除 DropDownBox UI 中显示的文本。这可确保选择新位置时 UI 反映更新后的状态。