AppFocusService

Handling app focus The AppFocusService allows developers to be notified when their apps become visible on the screen. Common reasons your app may be running but not be on screen are: it's still in the middle of launching and being revealed by a system animation, or it is being covered by a system window such as a notification. This service is useful for apps that require a high degree of user interactivity, like a game where you'll want to pause when a notification covers your app window. It can be also used for apps that want to sync up an intro animation to the end of the system animation that occurs before your app is visible. More...

Collaboration diagram for AppFocusService:

Classes
struct	AppFocusHandlers

Typedefs
typedef void(*	AppFocusHandler) (bool in_focus)

Functions
void	app_focus_service_subscribe_handlers (AppFocusHandlers handlers)
void	app_focus_service_subscribe (AppFocusHandler handler)
void	app_focus_service_unsubscribe (void)

Detailed Description

Handling app focus The AppFocusService allows developers to be notified when their apps become visible on the screen. Common reasons your app may be running but not be on screen are: it's still in the middle of launching and being revealed by a system animation, or it is being covered by a system window such as a notification. This service is useful for apps that require a high degree of user interactivity, like a game where you'll want to pause when a notification covers your app window. It can be also used for apps that want to sync up an intro animation to the end of the system animation that occurs before your app is visible.

Typedef Documentation

AppFocusHandler

typedef void(* AppFocusHandler) (bool in_focus)

Callback type for focus events

Parameters

in_focus

True if the app is gaining focus, false otherwise.

Function Documentation

app_focus_service_subscribe()

void app_focus_service_subscribe

(

AppFocusHandler

handler

)

Subscribe to the focus event service. Once subscribed, the handler gets called every time the app focus changes.

Note

Calling this function is equivalent to

app_focus_service_subscribe_handlers((AppFocusHandlers){
  .will_focus = handler,
});

Out focus events are triggered when a modal window is about to open and cover the app.

In focus events are triggered when a modal window which is covering the app is about to close.

Parameters

handler

A callback to be called on will-focus events.

app_focus_service_subscribe_handlers()

void app_focus_service_subscribe_handlers

(

AppFocusHandlers

handlers

)

Subscribe to the focus event service. Once subscribed, the handlers get called every time the app gains or loses focus.

Parameters

handler

Handlers which will be called on will-focus and did-focus events.

See also

AppFocusHandlers

app_focus_service_unsubscribe()

void app_focus_service_unsubscribe

(

void

)

Unsubscribe from the focus event service. Once unsubscribed, the previously registered handlers will no longer be called.