Android UI Overlays
This document is under development and will be updated as new versions of software are released.
Android is a diverse mobile operating system developed by Google and released as open source, a project nominally guided by the Open Handset Alliance. There are many, many Android devices, and most run customized interfaces, or 'UI Overlays', that change the functionality of the device. Some of these overlays are only cosmetic changes, while others make deep modifications to the core OS to implement specific functionality intended to differentiate the device from those made by other manufacturers.
Unfortunately, there are a number of problems inherent in those UI Overlays:
- Overlays dramatically increase the amount of effort require to test, customize, and deploy OS updates, thus delaying updates or causing manufacturers to consider never deploying them at all.
- Overlays often switch out base Android components such as the email client, calendar, and app store for customized, differentiated (sometimes more limited, sometimes more full featured) versions that do not always perform in predictable manners. Some of these components actively interfere with security policies, handle email, contacts, and events in unexpected ways, and/or cause information leaks that pose risks to the data on the device.
- Overlays can result an entirely different user experience, re-arranging or eliminating some settings and adding others. This makes it very difficult to establish documentation common to Android, and a user of one Android device may not be familiar with the operation of another, similar device.
Common UI Overlays
TouchWiz is present on most Samsung devices. TouchWiz contains modified versions of the calendar, email, and contacts application. Security policies often, but do not always, apply properly, though passcode lock policies are sometimes interpreted in unexpected ways on the device.
MotoBLUR is present on most Motorola devices, and is frequently the most problematic of the UI overlays. On many Motorola devices, establishing Exchange Active Sync connectivity via the completely custom 'corporate sync' client requires agreement to an excessively onerous End User License Agreement that, among other things, indicates that Motorola claims rights to any data processed by that client. Additionally, on some Motorola devices like the DROID RAZR MAXX, very precarious and temporary setups must be established to consumer email services before enterprise email access can be established.
Some MotoBLUR devices tout advanced Enterprise-focused features like encryption and additional security protocol support. While the encryption function is an improvement over the unencrypted storage in Android 2.x, the customized implementations of the 'Enterprise' mailer are sufficiently unpredictable as to be unwise, particularly for those with more complex email and calendaring setups.
Sense UI is one of the more well received UI overlays, and is present on most HTC devices. Sense UI implements an extensive custom interface, and often (but not always) custom versions of the email, contacts, and calendar apps. Some versions of Sense can cause event duplications, and some do not display nested email folders. In some cases, Sense allows alternatives to PIN or password screen locks, such as pattern unlock.