[flutter_local_notifications] add AndroidNotificationCategory to make Android categories more accessible

[lucasribolli]

Add all the Android categories values with documentation in AndroidNotificationCategory class from https://developer.android.com/reference/androidx/core/app/NotificationCompat.html#constants_2.

The goal is make this property more accessible for the users. It results in a little breaking change since the current category property is of String type. However, I believe it’s worth using it.

Also, I tried to make it just like LinuxNotificationCategory of Linux package to keep a pattern.

[MaikuB]

Thanks for the PR. I agree with the intent behind the PR but are you able to elaborate more on what you mean by making it more accessible?

As for the changes within the PR itself, comments I have are

• as this is a breaking change and there is a 10.0 prerelease at the moment with branch on it too, could this PR target the 10.0.0 branch?
• the semantics are slightly awkward in that it's calling constructor methods even though they're constant constructors. Can this be changed so it looks like a field/property is referenced rather than a method? An example of what I mean is a change in the implement so that rather than having consumers have AndroidNotificationCategory.alarm() in their code, they would reference AndroidNotificationCategory.alarm instead

[lucasribolli]

are you able to elaborate more on what you mean by making it more accessible?

Sure! Make it more accessible means make it easier to use. Nowadays, the consumer who wants to add category to his Android notification needs to open the API docs, search for the category and then copy the specific String value and paste it in his code. It would be easier to have all values inside Dart plugin code.

I am sorry if the accessible word does not mean that, my English is still WIP :/

as this is a breaking change and there is a 10.0 prerelease at the moment with branch on it too, could this PR target the 10.0.0 branch?

Make sense, I change it.

the semantics are slightly awkward in that it's calling constructor methods even though they're constant constructors. Can this be changed so it looks like a field/property is referenced rather than a method? An example of what I mean is a change in the implement so that rather than having consumers have AndroidNotificationCategory.alarm() in their code, they would reference AndroidNotificationCategory.alarm instead

Of course, it sounds better to access the properties in that way

I am going to update the PR with the proposed changes.
Thanks for reviewing!

[MaikuB]

Thanks for making the changes. Given what you said, do you think you could add links to to the Android API docs for each category? For example, https://developer.android.com/reference/androidx/core/app/NotificationCompat#CATEGORY_CALL() is the one for the call category

Edit: will update the semantics for Linux version after this is merged in for consistency

[lucasribolli]

I add it, of course. It will be similar to AndroidServiceForegroundType.
The links need a () at the end so I will replace it by %28%29 in encoded link. It works the same and does not add one more ) in documentation from consumers vision