I'am trying to show a LazyColumn inside an alert dialog so the user can choose between a list of items, and click on it. The alert dialog will show without problem, i can click on any item which is on screen and close it, but as soon as i try to scroll between the items, it will give the following error:
E/InputEventReceiver: Exception dispatching input event.
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.app, PID: 22418
java.lang.IllegalArgumentException: Failed requirement.
at androidx.compose.ui.node.MeasureAndLayoutDelegate.doRemeasure(MeasureAndLayoutDelegate.kt:177)
at androidx.compose.ui.node.MeasureAndLayoutDelegate.remeasureAndRelayoutIfNeeded(MeasureAndLayoutDelegate.kt:228)
at androidx.compose.ui.node.MeasureAndLayoutDelegate.access$remeasureAndRelayoutIfNeeded(MeasureAndLayoutDelegate.kt:38)
at androidx.compose.ui.node.MeasureAndLayoutDelegate.measureAndLayout(MeasureAndLayoutDelegate.kt:201)
at androidx.compose.ui.platform.AndroidComposeView.measureAndLayout(AndroidComposeView.android.kt:662)
at androidx.compose.ui.platform.AndroidComposeView.handleMotionEvent-8iAsVTc(AndroidComposeView.android.kt:1073)
at androidx.compose.ui.platform.AndroidComposeView.dispatchTouchEvent(AndroidComposeView.android.kt:1059)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3920)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:3594)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3920)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:3594)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3920)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:3594)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3920)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:3594)
at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:913)
at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1957)
at android.app.Dialog.dispatchTouchEvent(Dialog.java:1162)
at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:871)
at android.view.View.dispatchPointerEvent(View.java:15458)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:7457)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:7233)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:6595)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:6652)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:6618)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:6786)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:6626)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:6843)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:6599)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:6652)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:6618)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:6626)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:6599)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:9880)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:9718)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:9671)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:10014)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:220)
at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method)
at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:200)
at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:9960)
at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:10056)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1010)
at android.view.Choreographer.doCallbacks(Choreographer.java:809)
at android.view.Choreographer.doFrame(Choreographer.java:737)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:995)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:246)
at android.app.ActivityThread.main(ActivityThread.java:8595)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
I/Process: Sending signal. PID: 22418 SIG: 9
This is the AlertDialog code:
AlertDialog(
onDismissRequest = { showDialog.value = false },
modifier = Modifier.fillMaxHeight(.80f),
text = {
LazyColumn{
items(30){ i ->
Text(text = i.toString())
}
}
},
buttons = {
Button(onClick = { /*TODO*/ }) {
Text(text = "Cancel")
}
}
)
The same problem happens to me although I found that if I use the Material3 library scrolling is not a problem anymore:
implementation "androidx.compose.material3:material3:1.0.0-alpha03"
AlertDialog(
onDismissRequest = { },
modifier = Modifier.fillMaxHeight(0.8f),
text = {
LazyColumn() {
items(30) { i ->
Text(text = i.toString())
}
}
},
dismissButton = {
Button(onClick = { /*TODO*/ }) {
Text(text = "Cancel")
}
}
)
Make sure to import:
import androidx.compose.material3.AlertDialog
I don't know if this is the correct answer but I hope it helps in any case.
Another workaround is the usage of the base androidx.compose.ui.window.Dialog. This Dialog works without any crashes when using the LazyColumn:
#Composable
#Preview(showBackground = true)
fun SimpleDialog(onDismissRequest: () -> Unit = {}) {
Dialog(
onDismissRequest = onDismissRequest,
content = {
Surface(shape = RoundedCornerShape(8.dp)) {
Column(
modifier = Modifier.padding(8.dp),
) {
Text(text = "Simple Dialog", style = MaterialTheme.typography.h6)
LazyColumn(
modifier = Modifier.height(150.dp),
content = {
items(30){ i ->
Text(text = i.toString())
}
}
)
Button(onClick = onDismissRequest) {
Text("Cancel")
}
}
}
},
)
}
Related
I'm created custom dialog from common class in ini
init {
activity.setContent {
CustomDialog(viewModel)
}
}
#Composable
fun CustomDialog(viewModel: ViewModel){
Dialog(
onDismissRequest = { },
properties = DialogProperties(dismissOnBackPress = true, dismissOnClickOutside = true)
) {
}
}
But under dialog background is an empty activity, but must be a preference activity.
Not correct composable:
correct dialog via XML:
I tried, but didn't help
Surface(modifier = Modifier.background(Color.Transparent)) {
CustomDialog(viewModel)
}
```
Exampe:
Dialog(onDismissRequest = { onDismissRequest() }, properties = DialogProperties()) {
Column(
modifier = Modifier
.wrapContentSize()
.background(
color = MaterialTheme.colors.surface,
shape = RoundedCornerShape(size = 16.dp)
).clip(shape = RoundedCornerShape(size = 16.dp))
) {
//.....
}
}
Found solution:
dialog?.window?.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
dialog?.window?.setDimAmount(0.0f)
I'm learning Kotlin and Compose Desktop and I'm trying refresh the UI before fetch data from an API.
But the request is running inside a runBlocking, thus the UI freezes until request is completed.
This is my code, everything works.
val client = HttpClient(CIO)
#OptIn(ExperimentalComposeUiApi::class)
#Composable
#Preview
fun App() {
var text by remember { mutableStateOf("Test button") }
Box(
modifier = Modifier.fillMaxSize(),
contentAlignment = Alignment.Center
) {
Column(
modifier = Modifier.padding(50.dp)
) {
Button(
onClick = {
text = "Wait..."//How to refresh UI to display this text?
runBlocking {
delay(5000)//blocking test
val response: HttpResponse = client.request("https://myapi.com/") {
// Configure request parameters exposed by HttpRequestBuilder
}
if (response.status == HttpStatusCode.OK) {
val body = response.body<String>()
println(body)
} else {
println("Error has occurred")
}
}
text = "Test button"
},
modifier = Modifier.fillMaxWidth()
) {
Text(text)
}
OutlinedTextField(
value = "",
singleLine = true,
onValueChange = { text = it }
)
}
}
}
fun main() = application {
Window(
onCloseRequest = ::exitApplication,
state = WindowState(size = DpSize(350.dp, 500.dp)),
title = "Compose test"
) {
App()
}
}
How to achieve that?
The problem here is that you are using runBlocking at all.
The most straightforward solution for your case would be to replace your runBlocking {} with a coroutine scope. At the top of your App() function, create your scope: val scope = rememberCoroutineScope(), then instead of runBlocking you can say scope.launch {}.
New code would be:
#OptIn(ExperimentalComposeUiApi::class)
#Composable
#Preview
fun App() {
var text by remember { mutableStateOf("Test button") }
val scope = rememberCoroutineScope()
Box(
modifier = Modifier.fillMaxSize(),
contentAlignment = Alignment.Center
) {
Column(
modifier = Modifier.padding(50.dp)
) {
Button(
onClick = {
text = "Wait..."//How to refresh UI to display this text?
scope.launch {
delay(5000)//blocking test
val response: HttpResponse = client.request("https://myapi.com/") {
// Configure request parameters exposed by HttpRequestBuilder
}
if (response.status == HttpStatusCode.OK) {
val body = response.body<String>()
println(body)
} else {
println("Error has occurred")
}
}
text = "Test button"
},
modifier = Modifier.fillMaxWidth()
) {
Text(text)
}
OutlinedTextField(
value = "",
singleLine = true,
onValueChange = { text = it }
)
}
}
}
I saw one comment say to use LaunchedEffect() but this won't work in your case since you can't use that in an onClick since it's not a Composable.
When I double click the same item or if I go to each composable screen very quickly i receive an error, How do I solve this problem? I tried changing few things but I just can't solve it and I can't find any resources to fix this problem.
Bottom Navigation implementation
#Composable
fun BottomNav(
navController: NavController,
bottomNavState: MutableState<Boolean>,
) {
val navItems = listOf(
Screen.HomeScreen,
Screen.BookmarkScreen,
Screen.MyRecipesScreen,
Screen.FavouriteScreen
)
AnimatedVisibility(
visible = bottomNavState.value,
enter = slideInVertically(initialOffsetY = { it }),
exit = slideOutVertically(targetOffsetY = { it }),
content = {
BottomNavigation(
backgroundColor = Color.White,
elevation = 12.dp
) {
val bottomNavBackStackEntry by navController.currentBackStackEntryAsState()
val currentDestination = bottomNavBackStackEntry?.destination
navItems.forEach { item ->
BottomNavigationItem(
icon = {
Icon(painter = painterResource(id = item.icon), contentDescription = "")
},
label = {
Text(text = item.title)
},
selected = currentDestination?.hierarchy?.any { it.route == item.route } == true,
onClick = {
navController.navigate(item.route) {
popUpTo(navController.graph.findStartDestination().id) {
saveState = true
}
launchSingleTop = true
restoreState = true
}
},
selectedContentColor = Color.Black,
unselectedContentColor = Color.LightGray,
alwaysShowLabel = true,
)
}
}
}
)
}
Error Received
2022-03-05 11:50:10.183 8460-8460/com.im.cookgaloreapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.im.cookgaloreapp, PID: 8460
java.lang.IllegalStateException: Already attached to lifecycleOwner
at androidx.lifecycle.SavedStateHandleController.attachToLifecycle(SavedStateHandleController.java:38)
at androidx.lifecycle.SavedStateHandleAttacher.onRecreated(SavedStateHandleSupport.kt:139)
at androidx.savedstate.Recreator.reflectiveNew(Recreator.java:90)
at androidx.savedstate.Recreator.onStateChanged(Recreator.java:62)
at androidx.lifecycle.LifecycleRegistry$ObserverWithState.dispatchEvent(LifecycleRegistry.java:360)
at androidx.lifecycle.LifecycleRegistry.forwardPass(LifecycleRegistry.java:271)
at androidx.lifecycle.LifecycleRegistry.sync(LifecycleRegistry.java:313)
at androidx.lifecycle.LifecycleRegistry.moveToState(LifecycleRegistry.java:151)
at androidx.lifecycle.LifecycleRegistry.setCurrentState(LifecycleRegistry.java:121)
at androidx.navigation.NavBackStackEntry.updateState(NavBackStackEntry.kt:188)
at androidx.navigation.NavBackStackEntry.setMaxLifecycle(NavBackStackEntry.kt:154)
at androidx.navigation.NavController.updateBackStackLifecycle$navigation_runtime_release(NavController.kt:987)
at androidx.navigation.NavController.dispatchOnDestinationChanged(NavController.kt:892)
at androidx.navigation.NavController.navigate(NavController.kt:1726)
at androidx.navigation.NavController.navigate(NavController.kt:1658)
at androidx.navigation.NavController.navigate(NavController.kt:1980)
at androidx.navigation.NavController.navigate$default(NavController.kt:1975)
at androidx.navigation.NavController.navigate(NavController.kt:1961)
at com.im.cookgaloreapp.ui.components.BottomNavigationKt$BottomNav$3$1$1$2.invoke(BottomNavigation.kt:67)
at com.im.cookgaloreapp.ui.components.BottomNavigationKt$BottomNav$3$1$1$2.invoke(BottomNavigation.kt:57)
at androidx.compose.foundation.ClickableKt$clickable$4$gesture$1$2.invoke-k-4lQ0M(Clickable.kt:153)
at androidx.compose.foundation.ClickableKt$clickable$4$gesture$1$2.invoke(Clickable.kt:142)
at androidx.compose.foundation.gestures.TapGestureDetectorKt$detectTapAndPress$2$1$1.invokeSuspend(TapGestureDetector.kt:223)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
at kotlinx.coroutines.DispatchedTaskKt.resume(DispatchedTask.kt:178)
at kotlinx.coroutines.DispatchedTaskKt.dispatch(DispatchedTask.kt:166)
at kotlinx.coroutines.CancellableContinuationImpl.dispatchResume(CancellableContinuationImpl.kt:397)
at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl(CancellableContinuationImpl.kt:431)
at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl$default(CancellableContinuationImpl.kt:420)
at kotlinx.coroutines.CancellableContinuationImpl.resumeWith(CancellableContinuationImpl.kt:328)
at androidx.compose.ui.input.pointer.SuspendingPointerInputFilter$PointerEventHandlerCoroutine.offerPointerEvent(SuspendingPointerInputFilter.kt:511)
at androidx.compose.ui.input.pointer.SuspendingPointerInputFilter.dispatchPointerEvent(SuspendingPointerInputFilter.kt:406)
at androidx.compose.ui.input.pointer.SuspendingPointerInputFilter.onPointerEvent-H0pRuoY(SuspendingPointerInputFilter.kt:419)
at androidx.compose.ui.input.pointer.Node.dispatchMainEventPass(HitPathTracker.kt:310)
at androidx.compose.ui.input.pointer.Node.dispatchMainEventPass(HitPathTracker.kt:297)
at androidx.compose.ui.input.pointer.Node.dispatchMainEventPass(HitPathTracker.kt:297)
at androidx.compose.ui.input.pointer.Node.dispatchMainEventPass(HitPathTracker.kt:297)
at androidx.compose.ui.input.pointer.Node.dispatchMainEventPass(HitPathTracker.kt:297)
at androidx.compose.ui.input.pointer.NodeParent.dispatchMainEventPass(HitPathTracker.kt:179)
at androidx.compose.ui.input.pointer.HitPathTracker.dispatchChanges(HitPathTracker.kt:98)
at androidx.compose.ui.input.pointer.PointerInputEventProcessor.process-BIzXfog(PointerInputEventProcessor.kt:80)
2022-03-05 11:50:10.184 8460-8460/com.im.cookgaloreapp E/AndroidRuntime: at androidx.compose.ui.platform.AndroidComposeView.sendMotionEvent-8iAsVTc(AndroidComposeView.android.kt:1205)
at androidx.compose.ui.platform.AndroidComposeView.handleMotionEvent-8iAsVTc(AndroidComposeView.android.kt:1155)
at androidx.compose.ui.platform.AndroidComposeView.dispatchTouchEvent(AndroidComposeView.android.kt:1095)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3118)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2799)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3118)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2799)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3118)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2799)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3118)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2799)
at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:488)
at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1871)
at android.app.Activity.dispatchTouchEvent(Activity.java:4125)
at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:446)
at android.view.View.dispatchPointerEvent(View.java:14568)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:6016)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:5819)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:5310)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:5367)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:5333)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:5485)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:5341)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:5542)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:5314)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:5367)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:5333)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:5341)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:5314)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:8080)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:8031)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:7992)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:8203)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:220)
at android.os.MessageQueue.nativePollOnce(Native Method)
at android.os.MessageQueue.next(MessageQueue.java:335)
at android.os.Looper.loop(Looper.java:183)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
I'm facing the same problem using the latest compose navigation dependency 2.5.0-alpha03.
I don't know why it's happening.
Philip Dukhov is right, you should report this issue.
Here is a dirty workaround :
try {
// The navigation code that throw this exception
} catch (e: IllegalStateException) {
if (e.message != "Already attached to lifecycleOwner") {
throw e
} else {
// You can log the exception if you want
}
}
I was experiencing the same bug in 2.5.0-alpha01, 2.5.0-alpha02, and 2.5.0-alpha03 but finally was able to get it to work in 2.5.0-alpha04. 4th time is the charm!
This is indeed a navigation error. The problem is that the Tab is repeatedly clicked. The temporary solution is to return equally.
NavigationBarItem(
icon = {
Icon(painterResource(id = screen.icon), contentDescription = screen.route)
},
selected = currentRoute == screen.route,
onClick = {
if (currentRoute == screen.route) {
return#NavigationBarItem
}
navController.navigate(screen.route) {
popUpTo(navController.graph.findStartDestination().id) {
saveState = true
}
launchSingleTop = true
restoreState = true
}
}
)
There is indeed a bug in 2.5.0-alpha03. Remitting to 2.5.0-alpha02 fixed the bug
implementation 'androidx.navigation:navigation-compose:2.5.0-alpha03'
to
implementation 'androidx.navigation:navigation-compose:2.5.0-alpha02'
fixed it for me
In its simplest form I have this dialog:
#Composable
fun MyDialog(
showDialogState: MutableState<Boolean>
) {
if (showDialogState.value) {
AlertDialog(onDismissRequest = { showDialogState.value = false },
// Other irrelevant attributes have been omitted
)
}
}
How can I trigger "onDismissRequest" on this composable in Robolectric?
This is usually how I build my composable tests by the way:
#Config(sdk = [Build.VERSION_CODES.O_MR1])
#RunWith(AndroidJUnit4::class)
#LooperMode(LooperMode.Mode.PAUSED)
class MyDialogTest {
#get:Rule
val composeTestRule = createComposeRule()
#Test
fun `MyDialog - when showing state and dismissed - changes showing state`() {
val state = mutableStateOf(true)
composeTestRule.setContent {
MyDialog(
showDialogState = state
)
}
// TODO: How do I trigger dismiss!?
assertFalse(state.value)
}
}
Compose version: 1.1.0-rc01
Android Gradle Plugin version: 7.0.4
Robolectric version: 4.7.3
I don't think this is possible at the moment. I have written this test to confirm:
val onButtonPressed = mock<() -> Unit>()
composeTestRule.setContent {
Scaffold(topBar = {
TopAppBar {
Text(text = "This test does not work")
}
}) {
AlertDialog(
onDismissRequest = {},
properties = DialogProperties(
dismissOnBackPress = true,
dismissOnClickOutside = true
),
title = { Text(text = "This is a dialog")},
confirmButton = { Button(onClick = {}) {
Text(text = "Confirm")
}}
)
Column(modifier = Modifier.fillMaxSize()) {
Spacer(modifier = Modifier.weight(1f))
Button(onClick = onButtonPressed) {
Text(text = "test")
}
}
}
}
composeTestRule.onNode(isDialog()).assertExists()
composeTestRule.onNodeWithText("test", ignoreCase = true).performClick()
verify(onButtonPressed).invoke()
composeTestRule.onNode(isDialog()).assertDoesNotExist()
Even though the button is "behind" the dialog, it receives click events without dismissing the dialog.
Manual testing has confirmed that the implementation works, so perhaps a UIAutomator test could automate this, but that seems like an overly complicated way of solving this issue.
I quote the official documentation:
Dismiss the dialog when the user clicks outside the dialog or on the
back button. If you want to disable that functionality, simply use an
empty onCloseRequest.
https://foso.github.io/Jetpack-Compose-Playground/material/alertdialog/
I was testing Compose and navigation and noticed strange behavior (nav ver: androidx.navigation:navigation-compose:2.4.0-alpha10)
In this example, is a screen to check if the app is up to date or not (boolean var in the code for simple test), and if yes, navigate to other screen.
The big issue I found here was that when automating the navigation, the second screen switches to the first one very quickly. But if the navigation is done with the click of a button, for example, nothing strange happens...
MainActivity file code:
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
AppTheme {
Surface(color = MaterialTheme.colors.background) {
val navController = rememberNavController()
NavHost(
navController = navController,
startDestination = "first_screen"
) {
composable(route = "first_screen") {
FirstScreen(navController)
}
composable(route = "second_screen") {
SecondScreen(navController)
}
}
}
}
}
}
}
FirstScreen file code:
#Composable
fun FirstScreen(navController: NavController) {
val isAppUpdated = true // switch case
Scaffold(
topBar = {
TopAppBar {
Text(text = "First Screen Bar")
}
}
) {
Column(
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Center,
modifier = Modifier.fillMaxSize()
) {
Text(
text = "First Screen",
textAlign = TextAlign.Center,
style = MaterialTheme.typography.h4
)
if (!isAppUpdated) OutdatedApp()
else {
// Two options to navigate: with compose button or automatically
// UpdatedApp {
// navigateToSecondScreen(navController)
// }
navigateToSecondScreen(navController)
}
}
}
}
#Composable
fun OutdatedApp() {
Text(
text = "Your app is out of date, consider updating it!",
textAlign = TextAlign.Center,
style = MaterialTheme.typography.body1
)
}
#Composable
fun UpdatedApp(onClick: () -> Unit) {
Button(
onClick = { onClick() }
) {
Text(
text = "Navigate to Second Screen",
style = MaterialTheme.typography.button
)
}
}
private fun navigateToSecondScreen(navController: NavController) {
navController.navigate(route = "second_screen") {
launchSingleTop
popUpTo(route = "first_screen") { inclusive = true }
}
}
SecondScreen file code:
#Composable
fun SecondScreen(navController: NavController) {
Scaffold(
topBar = {
TopAppBar {
Text(text = "Second Screen Bar")
}
}
) {
Column(
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Center,
modifier = Modifier.fillMaxSize()
) {
Text(
text = "Second Screen",
textAlign = TextAlign.Center,
style = MaterialTheme.typography.h4
)
}
}
}
Can anyone explain what happens in these cases?
And any solution to implement this logic?
EDIT
I did another test without Scaffold on FirstScreen and it looks like this problem didn't happen...
SOLUTION
Philip's answer
LaunchedEffect's documentation