RxBinding | RxJava binding APIs for Android 's UI widgets | Reactive Programming library

Disabling and reenabling the button is much more straightforward, but you can use backpressure:

I added .map and changed the order to

When you do toDoDao.insert(someToDo), you must ask yourself, how is this code working? abstact interface functions can't be called, then where is the implementation of insert(ToDo) function?

Implementation of all the functions defined in the @Dao interface is in the YourDao_impl (impl is short for implementation, implementation of your @Dao interface) which is automatically generated by the room annotation processor.

To appreciate the use of _impl class you must understand that When reading or writing to SQL databases, there are multiple steps that needs to be performed almost always. in most cases these steps would look as following:

If the app works in debug but not in release, it's probably because Proguard minified your classes and deserialization no longer works due to different (shorter) class and property names.

Make sure you have this in your proguard:

Dependencies: ./gradlew :dependencies

This code is OK.

From RxBinding::Ptr T can't be deduced, as it's a non-deduced context because of nested types (see example 1) under Non-deduced contexts on cppreference and godbolt example), so the original example shouldn't have worked with argument deduction. With that in mind having typename RxBinding::Ptr ...args will work the same way as it did before (note the syntax having ... before the argument name). I changed the variadic type template to Ts instead of T, to better represent that it's variadic.

With auto binding = makeValueBinding(std::make_tuple( /* what do do here with args ?? */ )); you can use a pack expansion with the pattern args->Get(), so the final line will be
auto binding = makeValueBinding(std::make_tuple(args->Get()...));.

Creation of the variables s0, s1, and so on is not trivial, so I'll get back to it at the end.

To make the final subscribtion, you will need to use a helper function to expand the tuple:

init(original:items:) is a copy initializer. It takes an already existing instance of the struct and makes a new one that is identical except that it changes what's in the items property.

So in a protocol declaration, init(original: Self, items: [Item]) means: "You hand me an already existing instance of whatever this type is that is conforming to me, the protocol, and we'll make a new instance that copies it while changing its items."

And that is exactly what the example does. It's easier to see if you put it all together, like this:

After sleeping on it, I figured it out.

I changed RxTextView.textChanges to RxTextView.textChangeEvents. This allowed me to query the CharSequence's text value (using text() method provided by textChangeEvents) even if it's empty. Due to some other changes (not really relevant to what I was asking in this question) I was also able to reduce some of the conditional code too. I'm just putting that out there in case someone comes across this and is curious about these changes. The takeaway is that you can get that empty emission using RxTextView.textChangeEvents.

Here is my new Observer: