breadcrumbs: Design Documents > page_name: system-notifications title: system notifications
ChromeOS has several types of system status and some of them should be notified to the user. This document summarizes which types of notifications are currently used and what kind of UI flow is necessary here.
The notifications are usually generated through the internal C++ API for the desktop notifications, which will appear as the rich notification as well.
Sometimes normal notifications should be blocked due to the current system status. For example, all notifications should be queued during the lock screen, and they should appear when unlocked. It also should be blocked when fullscreen state; notifications should be annoying when the user watches YouTube videos, or has a presentation (note: the notifications should appear in immersive fullscreen mode instead, because the shelf / message center UI is visible in such case).
However, the system status could be so important that they should appear in such cases. This does not mean all system notifications should appear; some could be misleading. For example, the notification for taking screenshot would behave as same as the normal notifications, so it should not appear in the lock screen. In addition, screenshot notification has the message to ‘click to view’ but click should not work in lock screen. On the other hand, connecting display would be okay to be notified even in the lock screen, it just notifies the new system status.
See also the notification blocking code update design doc.
message center?ComponentSourceMessageShow Always? (“System”)TimeoutSecure? (Show on Lock Screen)Customize? (can be disabled)Click ActionButtonTriggersYesdisplayDisplayErrorObserverCould not mirror displays...NoYesYesNoNonedisplay connection YesdisplayDisplayErrorObserverThat monitor is not supportedNoYesYesNoNonedisplay connection YesdisplayResolutionNotificationController..resolution was changed to...YesBothNoNoAccept / Revert changeAccept / Revert changesettings change from chrome://settings/displayYesdisplayScreenCaptureTrayItem... is sharing your screenYesNoNoNoneStop CaptureappsYesdisplayScreenShareTrayItemSharing control of your screen...YesNoNoNoneStop ShareappsYesdisplayScreenshotTakerScreenshot takenNoYesNoYesShow FIles Appkeyboard shortcutYesdisplayTrayDisplayMirroring to...NoYesYesNoShow Display Settingssettings change from chrome://settings/display, and keyboard shortcutYesdisplayTrayDisplayExtending screen to...NoYesYesNoShow Display Settingssettings change from chrome://settings/display, and keyboard shortcutYesdisplayTrayDisplayDocked modeNoYesYesNoShow Display Settingsclose lidYeslanguageLocaleNotificationControllerThe language has changed from...NoNoNoNoAccept changeRevert changeloginNolanguageTrayAccessabilitySpoken feedback is enabled.*YesNoNonekeyboard shortcutNolanguageTrayCapsLockCAPS LOCK is on* YesNoNonekeyboard shortcutYeslanguageTrayIMEYour input method has changed...NoYesNoNoShow IME detailed viewkeyboard shortcutYesnetworkDataPromoNotificationGoogle Chrome will use mobile data...YesNo?NoPromo URL or settingsYesnetworknetwork_connectActivation of... requires a network connectionYesNo?NoShow SettingsYesnetworkNetworkStateNotifier...Your .. service has been activatedYesNo?NoShow SettingsYesnetworkNetworkStateNotifierYou may have used up your mobile data...YesNo?NoConfigure NetworkYesnetworkNetworkStateNotifierFailed to connect to network...YesNo?NoShow SettingsNonetworkTraySmsSMS from ...*NoNoShow SMS detailed viewNopowerTrayPowerBattery full OR % remaining*No / NeverYesNoNonelow batteryYespowerTrayPowerYour Chromebook may not charge...NoYesYesNoNoneusb charger connectedYesuserTrayLocallyManagedUserThis user is supervised by...YesNoNoNoNoneloginYesuserTraySessionLengthLimitThis session will end in...YesNoNoNoNonetimeout set by policy / sync / remaining time change NouserTrayUserYou can only have up to three accounts in multiple sign-in**YesNoNone