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[英]onValueChange of textfield is not triggered when selecting an option from exposed dropdownMenu composable, jetpack compose
[英]Jetpack Compose - DropdownMenu / Composable is placed outside (the) Box
我正在尝试为我的应用程序创建一个自定义 TopBar,并且我希望在屏幕的右上角显示一个DropdownMenu
。 我有一个Box
,其中包含Row
(带有一些文本和图标)和一个最初不显示的DropdownMenu
。 当我单击一个图标时,会显示DropdownMenu
,但在Box
之外,所以不在我想要的位置。 代码:
@Composable
private fun TopBar {
var expanded by remember { mutableStateOf(false) }
Box(
modifier = Modifier
.border(1.dp, Color.Black)
) {
Row(
verticalAlignment = Alignment.CenterVertically
) {
Text(
text = "Ride history",
maxLines = 1,
fontSize = 25.sp
)
Row(
modifier = Modifier.fillMaxWidth(),
horizontalArrangement = Arrangement.End
) {
IconButton(
onClick = {}) {
Icon(imageVector = Icons.Filled.Search, contentDescription = null)
}
IconButton(
onClick = { expanded = !expanded }) {
Icon(imageVector = Icons.Filled.Sort, contentDescription = null)
}
IconButton(
onClick = { findNavController().navigate(RideFragmentDirections.actionRideFragmentToSettingsFragment())}) {
Icon(imageVector = Icons.Filled.Settings, contentDescription = null)
}
}
}
DropdownMenu(
modifier = Modifier.align(Alignment.TopEnd),
expanded = expanded,
onDismissRequest = { expanded = false }
) {
DropdownMenuItem(onClick = {}) {
Text(text = "BlaBla")
}
DropdownMenuItem(onClick = {}) {
Text(text = "BlaBla")
}
}
}
}
我得到的:
(我在盒子周围放了一个边框来查看它的边界)
按下排序按钮后,会出现DropdownMenu
,但它位于Box
之外。 我希望它放在右上角,覆盖所有内容。 我错过了什么?
更新
@Composable
private fun TopBar() {
var expanded by remember { mutableStateOf(false) }
Box(
modifier = Modifier
.border(1.dp, Color.Black)
) {
Row(
verticalAlignment = Alignment.CenterVertically
) {
Text(
text = "Ride history",
maxLines = 1,
fontSize = 25.sp
)
Row(
modifier = Modifier.fillMaxWidth(),
horizontalArrangement = Arrangement.End
) {
IconButton(
onClick = {}
) {
Icon(imageVector = Icons.Filled.Search, contentDescription = null)
}
IconButton(
onClick = { expanded = !expanded }
) {
Icon(imageVector = Icons.Filled.Sort, contentDescription = null)
}
IconButton(
onClick = {}
) {
Icon(imageVector = Icons.Filled.Settings, contentDescription = null)
}
}
}
Box(
modifier = Modifier.fillMaxHeight().align(Alignment.TopEnd),
contentAlignment = Alignment.TopEnd
) {
DropdownMenu(
expanded = expanded,
onDismissRequest = { expanded = false }
) {
DropdownMenuItem(onClick = {}) {
Text(text = "BlaBla")
}
DropdownMenuItem(onClick = {}) {
Text(text = "BlaBla")
}
}
}
}
}
这产生:
根据Material 指南,下拉菜单应放置在元素下方。
要在 Compose 中使用DropdownMenu
获得此布局,您需要将其放入带有调用按钮的Box
中,如下所示:
Box {
IconButton(
onClick = { expanded = !expanded }
) {
Icon(imageVector = Icons.Filled.Sort, contentDescription = null)
}
DropdownMenu(
expanded = expanded,
onDismissRequest = { expanded = false }
) {
DropdownMenuItem(onClick = {}) {
Text(text = "BlaBla")
}
DropdownMenuItem(onClick = {}) {
Text(text = "BlaBla")
}
}
}
Output 其中Sort
是调用按钮:
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