How to add swipe behavior to the screens? - android-jetpack-compose

Question

We have bottom navigation in our app and we want to add swipe behavior into our screens so that if a user swipe to right/left then s/he should be navigated into next screen.
I know that Accompanist has HorizontalPager with Tabs. But I wonder if we can achieve that behavior with bottom navigation.

Answer 1

As you can see in the Material Design Guidelines:
Using swipe gestures on the content area does not navigate between views.
Also:
Avoid using lateral motion to transition between views.
But, if you really want to do this, you can do the this:
fun BottomNavSwipeScreen() {
// This scope is necessary to change the tab using animation
val scope = rememberCoroutineScope()
// I'm using a list of images here
val images = listOf(R.drawable.img1, ...)
// This page state will be used by BottomAppbar and HorizontalPager
val pageState = rememberPagerState(pageCount = images.size)
val scaffoldState = rememberScaffoldState()
Scaffold(
scaffoldState = scaffoldState,
bottomBar = {
BottomAppBar(
backgroundColor = MaterialTheme.colors.primary,
content = {
for (page in images.indices) {
BottomNavigationItem(
icon = {
Icon(Icons.Filled.Home, "Page $page")
},
// here's the trick. the selected tab is based
// on HorizontalPager state.
selected = page == pageState.currentPage,
onClick = {
// When a tab is selected,
// the page is updated
scope.launch {
pageState.animateScrollToPage(page)
}
},
selectedContentColor = Color.Magenta,
unselectedContentColor = Color.LightGray,
label = { Text(text = "Page $page") }
)
}
}
)
},
) {
HorizontalPager(
state = pageState,
offscreenLimit = 2
) { page ->
Image(
painterResource(id = images[page]),
null,
modifier = Modifier
.fillMaxSize(),
contentScale = ContentScale.Crop
)
}
}
}
Here is the result:

Answer 2

you can achieve this by using the animation library from compose:
https://developer.android.com/jetpack/compose/animation
And using the slideIntoContainer animation you can simulate the swipe effect:
composable("route1",
enterTransition = {
slideIntoContainer(
towards = AnimatedContentScope.SlideDirection.Right,
animationSpec = tween(
durationMillis = 250,
easing = LinearEasing // interpolator
)
)
},
exitTransition = {
slideOutOfContainer(
towards = AnimatedContentScope.SlideDirection.Left,
animationSpec = tween(
durationMillis = 250,
easing = LinearEasing
)
)
}) {
Screen1()
}
composable("route2",
enterTransition = {
slideIntoContainer(
towards = AnimatedContentScope.SlideDirection.Left,
animationSpec = tween(
durationMillis = 250,
easing = LinearEasing // interpolator
)
)
},
exitTransition = {
slideOutOfContainer(
towards = AnimatedContentScope.SlideDirection.Right,
animationSpec = tween(
durationMillis = 250,
easing = LinearEasing
)
)
}) {
Screen2()
}