The Android Status bar appears at the top of the screen. It displays status and notification icons as well as the current time. The following images show the icons you may see with a description.
The Status Bar
Status Icons
The status icons indicate the status of the phone. Network status icons turn green if you have a Google Account added to your phone and the phone is connected to Google services, for syncing your Gmail, Calendar events, contacts, for backing up your settings etc. The network icons turn white if you don’t have a Google Account or you’re connected to a Wi-Fi network that is not connected to the Internet.
Notification icons
The following icons indicate that you’ve received a notification. See “Managing notifications” on page 29 for information about responding to these notifications. In addition these icons, applications you install on your phone may use their own notification icons.