constraintlayout | Android layout component which allows you to position | User Interface library

To solve your problem you can just remove the OnResume method because you are initializing the array every time you change between fragments and that is the problem.

You're calling findViewById on your current Activity, which doesn't contain R.id.pizza_selection. Therefore I suspect you'll see

val pizzaDropdown = findViewById(R.id.pizzaSelection)

return null.

Try something like this:

So, this is not exactly what you want but at least it has the same layout as you want with a simpler approach.

So, the main challenges are:

• Taking a curve cutout on the CardView probably need to be built programmatically with canvas for a better result. But for simplicity, this is replaced by a BottomAppBar wrapped in a CoordinatorLayout in order to have the curve effect with the top circle/gap.

• Replacing the top View with Fab in order to have an Inset FAB by setting the layout_anchor to the BottomAppBar. Check material design for this.

  And having the cutout behavior requires to make the FAB like it doesn't exist by setting a transparent backgroundTint & removing the outlineProvider

• Making the top cutout (gap) of a particular row get overlapped to the top row like if it is a part of it. This works with the negative margin on the root view.

It seems that your HomeFragment doesn't have no parameters constructor. If you want to use fragment that requires constructor parameters you need to provide FragmentFactory to navigation component.

Add empty constructor HomeFragment() to HomeFragment, and it should work.

It seems like there are threading issues. The long-running task could be blocking the UI during its calculations.

How about trying the exhaustive algorithm on the background and updating the UI (progressbar in this case) when the calculation is complete from the background?

You can use the popular Kotlin-Coroutine to achieve this.

You can copy-paste try it:

You need to set your recyclerView on the main thread. Try to put the recyclerView in onCreate() and the .startListening() in the onStart.

As it was described in the reference:

When creating the NavHostFragment using FragmentContainerView or if manually adding the NavHostFragment to your activity via a FragmentTransaction, attempting to retrieve the NavController in onCreate() of an Activity via Navigation.findNavController(Activity, @IdRes int) will fail. You should retrieve the NavController directly from the NavHostFragment instead.

Looks like you should use

Bug fixed in beta08

References

https://issuetracker.google.com/issues/188855913

https://issuetracker.google.com/issues/188566058

Custom Composable are not heavy, really.

Anyway, try this:-

Create a Container of MaxWidth (maybe a BoxWithConstraints or something), keep its background transparent, set the height to wrap content. Create the tabs as usual, but keeping the bigger tab's icon size bigger explicitly using Modifier.size(Bigger Size).

After you have this setup, add another container inside this container with white background, covering a specific height of the original container. Let's say 60%

Now set the z-index of all the icons and tabs to higher than the z-index of this lastly added container. Use Modifier.zIndex for this. And viola, you have your Composable ready.

In order to set a specific percentage height of the inner container, you will need access to the height of the original container. Use BoxWithConstraints for that, or just implement a simple custom Layout Composable