Password Check UI Component

This folder contains the internal parts of the Password Check component. Files, classes and methods defined in here are not meant to be used outside of this package.

This document provides a brief overview of the architecture.

Component structure

This component follows the typical MVC structure that is widely used in Chrome on Android. The MVC structures separates logic from representation:

• The controller creates and connects all subcomponents and performs logic that affects the visual appearance of the component.
• The model keeps all state that affects the visual appearance of the component. Changes made to it are automatically propagated to the view by a Model-Change-Processor (MCP) as defined in //src/ui/android/java/src/org/chromium/ui/modelutil/
• The view is the representation of the component. It enforces styles and is mostly called by a view binder to set mutable properties.

A typical request to the Password Check component API that intends to change the visible appearance involves all component parts. For example if the API caller requests to show compromosed credentials:

1. The API caller asks the controller to show a set of credentials.
   1. The controller prepares and filters the credentials for display.
   2. The controller writes the prepared credentials into the model as ITEMS.
2. The MCP picks up model changes.
   1. The MCP identifies that the ITEMS property was changed.
   2. The MCP uses a ViewBinder to bind each settings item to the corresponding view (e.g. a COMPROMISED_CREDENTIAL item id would create or reuse a TextView with a button of options).
3. The view renders the changed credential list.
   1. The view may apply style, RTL settings and click event handlers.

Model

The model holds state and event listeners connected to the view. An MCP automatically notifies the listener about any change made to a property. To automate this Observer structure, the model is a PropertyModel as defined in //src/ui/android/java/src/org/chromium/ui/modelutil/. It is build by defining properties and constructing a model with them. The properties are located in the static PasswordCheckProperties class.

The model contains writable and readable properties. The readable properties are guaranteed to never change for the lifetime of the Password Check component:

• ITEMS which is the set of displayed credentials. The list itself will be modified (credentials will be added and removed) but the object remains the same which allows to permanently bind it to a list adapter.
• FRAGMET_EVENT_LISTENER which is the listener that reacts to view events. The mediator implements this interface.

The writable properties change over the course of the components lifetime:

• None so far

Controller

The controller of this model implements the PasswordCheckComponent interface as defined in public/ and contains all logic that affects the component's visual appearance. The controller consists of two parts:

• PasswordCheckCoordinator which implements the public interface and creates all parts of the component (model, mediator, view, etc.) and links them using MCPs.
• PasswordCheckMediator which handles request to the component API and changes the model accordingly.

View

The view contains all parts that are necessary to display the check UI. It consists of two parts:

• PasswordCheckViewBinder which maps model changes to the view. For the Password Check component, the ViewBinder also supports an Adapter that binds changes to the ITEMS property to the RecyclerView inside the bottom sheet.
• PasswordCheckSettingsView which displays all visible elements. Since it is a fragment that the SettignsLauncher needs to access, it is public.