Move adding of elements to main.xml, and get rid of an unnecessary LinearLayout.
Move ScrollView down to only the list of WLAN access points, so as to have a top header.
Remove unused variables, convert instance variables to local variables when it can be done, remove an unused import, and change from StringBuffer to StringBuilder.
Remove most of deprecated methods and constants, and use updated methods and constants.

At the moment, Notification.Builder requires API level 11, and NotificationCompat needs to be used for API level 8.

In addition, despite the labeling in the preferences, the main activity screen is kept on at full brightness, and the setting applies everywhere else.
Encapsulate ScanService's scanData and ScanData's lock, and provide getters for both.

This is the start of encapsulating non-private variables.
Use NotificationCompat.

Use NotificationCompat.Builder to build the notification. This allows using the newer class with v8-v10, but requires that the v4 Support Library be added as part of the compilation.