Fun | Wall messages app with authentication | Runtime Evironment library

You can use simply intent.putExtra instead of worrying about which variant like put_____Extra to use.

When extracting the value, you can use intent.extras to get the Bundle and then you can use get() on the Bundle and cast to the appropriate type. This is easier than trying to figure out which intent.get____Extra function to use to extract it, since you will have to cast it anyway.

The below code works whether your data class is Serializeable or Parcelable. You don't need to use arrays, because ArrayLists themselves are Serializeable, but you do need to convert from MutableList to ArrayList.

let returns the result of last expression inside it, in this case the value of builder.create(), a non-nullable AlertDialog.

Since you use ?.let, if activity is null, let won't be called, and you will effectively have null ?: throw....

builder.create() never returns null, so this throw expression is only reached when activity is null, so the error message doesn't make sense.

You are looking for ():

This is exactly the reason why coroutines were invented and how they differ from threaded concurrency. Coroutines don't block, but suspend (well, they can do both). And "suspend" isn't just another name for "block". When they suspend (e.g. by invoking join()), they effectively free the thread that runs them, so it can do something else somewhere else. And yes, it sounds like something that is technically impossible, because we are in the middle of executing the code of some function and we have to wait there, but well... welcome to coroutines :-)

You can think of it as the function is being cut into two parts: before join() and after it. First part schedules the background operation and immediately returns. When background operation finishes, it schedules the second part on the main thread. This is not how coroutines works internally (functions aren't really cut, they create continuations), but this is how you can easily imagine them working if you are familiar with executors or event loops.

delay() is also a suspending function, so it frees the thread running it and schedules execution of the code below it after a specified duration.

you need to create a factory to pass dynamic parameter to ViewModel like this:

I'm leaving this question up in case anyone else ever gets stuck in my situation, but the code works as it is meant to, I just committed a folly.

I didn't account for height changes with asynchronous image loading and as such, the list would not be at its saved position upon composable navigation, due to the list state being smaller than the screen height on returning to the composable.

However, If the images were given static containers to load into to that don't change their size, then upon back navigation, the composable would correctly display the saved list state.

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:

In ranges-v3, there is iterator_range which you can use to wrap the iterators into a range object.

In C++20, you can use std::span to wrap those iterators into an range object

You need to use the "remember" keyword for the recomposition to happen each time, as explained here: https://foso.github.io/Jetpack-Compose-Playground/general/state/

In short, your composable would look like this: