ios - Handoff action disappears after a period of time, need to call periodically? -

ios - Handoff action disappears after a period of time, need to call periodically? -

i'm implementing handoff in app. in app i've created handoff controller global entire application, phone call [useractivity becomecurrent] once. however, issue having handoff icon (app icon in lock screen , in app switcher) disappear after period of time (~10 minutes), , when relaunch app (i.e. calls becomecurrent again), handoff feature appear.

i not calling invalidate during 10 minutes, i've verified setting breakpoint.

so required phone call becomecurrent periodically? it's not written in documentation.

note: i've created handoff controller opposed implementing protocol in view controller because there many view controllers should allow handoff occur.

ios objective-c ios8 ios8.1 handoff