Much like a desktop or laptop computer, mobile devices organize icons and widgets on multiple screens for easy access. These are called the Home screens. One screen is designated as the main home screen, as shown in Figure 1. Additional home screens are accessed by sliding the main home screen to the left or right. Each home screen contains navigation icons, the main area where icons and widgets are accessed, and notification and system icons. The home screen indicator displays which home screen is currently being used.
The Android OS uses the system bar to navigate apps and screens. The system bar is always displayed at the bottom of every screen.
The system bar contains the following buttons, as shown in Figure 2:
- Back - Returns focus to the previous screen that was being used. If the on-screen keyboard is displayed, this button closes it. Continuing to press the Back button navigates to through each previous screen until the main home screen is displayed.
- Home - Returns focus to the last home screen used. If you are viewing a left or right home screen, the Home button opens the main home screen.
- Recent Apps - Opens thumbnail images of recently used apps. To open an app, touch its thumbnail. Swipe a thumbnail to remove it from the list.
- Menu - Shows additional options for the current screen if available.
Android devices often come with a default Google search app preinstalled. Touch and then type text into the box to search the device and the Internet for anything. Touch the microphone icon to enter the search using speech.
Some manufacturers add functionality to the Android OS. For example, some Samsung Android tablets have a feature called the Mini App Tray, which contains shortcuts to apps that can be used at any time. The Mini App Tray is opened by touching the arrow at the bottom of the screen. This feature is useful because the user does not have to navigate away from what they are doing to run a specific app.
Notification and System Icons
Each Android device has an area that contains system icons, such as the clock, battery status, and radio signal status for Wi-Fi and provider networks. Apps such as email, text messaging, and Facebook often display status icons to indicate communication activity.
To open the notification area on Android phones, touch and hold the top of the screen and swipe your finger down the screen. On Android tablets, touch the notification and system icons at the bottom of the screen, as shown in Figure 3. You can do the following when notifications are open:
- Respond to a notification by touching it.
- Dismiss a notification by swiping it off the screen to either side.
- Dismiss all notifications with the icon.
- Toggle often-used settings.
- Adjust the brightness of the screen.
- Open the Settings menu with the quick settings icon.
Instead of using the standard Android interface on its phones, HTC designed the TouchFLO interface over Android. With TouchFLO, use a special menu accessed by dragging your finger up the screen and then select common tasks by moving your finger left or right. TouchFLO was replaced by TouchFLO 3D. TouchFLO 3D had a collection of tabs along the bottom of the screen to easily access tasks. TouchFLO 3D has been replaced by HTC Sense. HTC Sense uses desktop apps and widgets, but has many interface modifications exclusive to HTC devices, such as locking screen apps and widgets and 3D home screen effects.