Tutorials for Simple-Stack

This repository contains tutorials for the simple-stack navigation library for Android.

1.) Using Backstack directly

In this step, we create a Backstack in our Activity to track our navigation state.

Then, we forward the necessary callbacks to make it work, even if there's a meteor storm or equivalent in Android's ecosystem.

We see that we can pass in any Parcelable and can navigate between them seamlessly, and handle a change between them in the handleStateChange callback.

Please note that this is the rawest form of simple-stack and will be greatly improved in step 2.

2.) Using Navigator to hide the lifecycle callbacks

In this step, we replace Backstack with Navigator, to see how much we can simplify the installation of a Backstack - down to just onCreate and onBackPressed.

3.) Setting the title text based on our navigation history

In this step, we can see how easy it is to set up any arbitrary state based on our current navigation history.

The example shows how to show the "back" button when there is an available screen to go back to, and how to change the title text accordingly.

4.) Using custom views instead of handling navigation state directly in the Activity

In this step, we can see how to use custom views (compound viewgroups) to create self-contained components that can contain their own views and manage their own behavior.

5.) Using fragments instead of custom views because that's also possible

In this step, we replace custom views (compound viewgroups) with Fragments, because they're more commonly found in the wild.

We can see that the Fragment framework (thanks to attach/detach/add/remove) is customizable enough that we can keep our Fragments exactly in the state as we expect them to be in based on our current navigation history.

6.) Using setHistory() to implement "conditional navigation"

In this step, we can see how to implement a simple splash screen using backstack.setHistory().

7.) Implementing "First Time User Experience" with simple-stack

In this step, we can see an example of implementing a "first time user experience" flow, following the behavior outlined in the guide "Jetpack Navigation: Conditional Navigation - First Time User Experience".

We also utilize the power of global services bound to the global scope, and a shared ViewModel bound to both shared identifier across screens (registration), and ViewModels bound to the scope of a given screen (ScopeKey / HasServices).

With this, we implement a FTUE where the user's navigation state and inputs are properly preserved across both configuration changes AND process death (as per Core App Quality Guidelines FN-S2).

8.) Result passing between scoped services

In this step, we can see how to use scoped services to pass results across screens.

By using serviceBinder.lookupService(), we can retrieve a service in the parent scope registered by a name (for example, the class name of the interface that handles the results).

This way, we can handle result passing between screens as a regular callback method.

9.) Adding RxJava and RxRelay to "First Time User Experience"

In this step, we'll add RxJava's BehaviorRelays and create ViewModel-internal subscriptions to provide field validation.

License

Copyright 2020 Gabor Varadi

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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limitations under the License.