# Content Settings and Site Settings in Android
[TOC]
## Overview
There are 3 main user-facing screens when it comes to displaying content
settings status to the user:
* [Site Settings](#Site-Settings) provides a link to `All Sites` and an
overview of all content settings. Supported by the
[SiteSettings](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SiteSettings.java)
class.
* [Settings Category](#Settings-Category) displays a specific content setting
in detail. This usually includes a toggle to enable/disable the content
setting browser-wide, any category-specific options, and lists of sites that
are `allowed`/`blocked`/`managed`. The same screen is used to display the
`All Sites` category which displays all sites that have any content settings
set. Supported by the
[SingleCategorySettings](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleCategorySettings.java)
class.
* [Website Settings](#Website-Settings) displays site-specific content
settings information. It displays a list of content settings that the site
is either allowed or blocked from and a button to reset all content settings
state for this site. Supported by the
[SingleWebsiteSettings](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java)
class.
All of these extend `PreferenceFragmentCompat` via `BaseSiteSettingsFragment`
and use a layout xml to define the preferences that form the screens.
## Site Settings
This screen is relatively static in nature, being a central hub for settings
categories.
[site_settings_preferences.xml](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/res/xml/site_settings_preferences.xml)
lists all preferences.
[configurePreferences()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SiteSettings.java?q=func:configurePreferences)
will remove some preferences based on command line switches and feature
availability.
[updatePreferenceStates()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SiteSettings.java?q=func:updatePreferenceStates)
goes through all preferences and configures cool things like: title, summary,
icon, and click listeners.
## Settings Category
This screen contains the logic used to display specific categories, as well as
the 'All sites' category."
[website_preferences.xml](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/res/xml/website_preferences.xml)
outlines the basic layout of the screen displaying the global settings for a
category.
The
[mCategory](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleCategorySettings.java?q=symbol:mCategory)
member holds which category needs to be displayed and is queried to dictate the
customization of the page.
[configureGlobalToggles()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleCategorySettings.java?q=func:configureGlobalToggles)
handles most of the customization of the screen. It will go through all
preferences and set their values, their visibility status as well as set up
preference change listeners.
[getInfoForOrigins()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleCategorySettings.java?q=func:getInfoForOrigins)
is used to fetch websites information via a
[WebsitePermissionsFetcher](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/WebsitePermissionsFetcher.java).
When the data is available it rebuilds the screen and adds the websites to the
`allowed`/`blocked`/`managed` lists.
[onPreferenceChange()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleCategorySettings.java?q=func:onPreferenceChange)
is the main listener of user input. When the user updates a preference, it will
identify the changed preference, use bridges to call the native code that
handles updating user content settings
([WebsitePreferenceBridge](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/WebsitePreferenceBridge.java)
and
[PrefServiceBridge](https://cs.chromium.org/chromium/src/chrome/browser/preferences/android/java/src/org/chromium/chrome/browser/preferences/PrefServiceBridge.java))
and then update the screen to ensure the new preference value is taken into
account including whatever ramifications that might have.
The `All Sites` list and the three `allowed`/`blocked`/`managed` lists are
populated with the custom
[WebsitePreference](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/WebsitePreference.java)
type of preference which allows clicks to navigate to the
[SingleWebsiteSettings](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java)
fragment.
## Website Settings
This screen is used to display the relevant information for a specific website.
[single_website_preferences.xml](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/res/xml/single_website_preferences.xml)
outlines the layout of the screen.
The underlying model object is a
[Website](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/Website.java)
object: the
[mSite](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java?q=symbol:mSite)
member. This is either directly provided by the activity initiator, or
alternately fetched via a
[SingleWebsitePermissionsPopulator](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java?q=symbol:SingleWebsitePermissionsPopulator)
based on the website address.
[displaySitePermissions()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java?q=func:displaySitePermissions)
is used to configure the screen and populate it with data from
[mSite](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java?q=symbol:mSite),
mostly by calling
[setUpPreference()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java?q=func:setUpPreference)
on every preference as well as specific custom setup functions.
[onPreferenceChange()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java?q=func:onPreferenceChange)
and
[onPreferenceClick()](https://cs.chromium.org/chromium/src/components/browser_ui/site_settings/android/java/src/org/chromium/components/browser_ui/site_settings/SingleWebsiteSettings.java?q=func:onPreferenceClick)
are responsbile for listening to user input and updating the content settings
accordingly.
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