I have followed the two videos about Screen time API in wwdc 21 and 22. Now i want to sheild some apps during sleeping, but I encounter some problems. Problem I faced I write my monitor and override intervalDidStart and intervalDidEnd . Here is a simplified version class Mymonitor: DeviceActivityMonitor { let store = ManagedSettingsStore() override func intervalDidStart(for activity: DeviceActivityName) { super.intervalDidStart(for: activity) store.shield.applications = selection.applicationToken } then I use deviceActivityCenter to start monitor func StartSleep (_ startTime : DateComponents) {   let schedule = DeviceActivitySchedule(intervalStart: startTime,                      intervalEnd: DateComponents(hour: 4, minute: 0),                      repeats: true                      )   let center = DeviceActivityCenter()   center.stopMonitoring([.daily])   try! center.startMonitoring(.daily, during: schedule) } However, when I use StartSleep. The applications is not shielded. I have noticed that I haven't use Mymonitor in any place. In the demo Code, it seems i just need to finish two parts (DeviceActivityMonitor and DeviceActivityCenter). But in the DeviceActivityCenter i do not use Mymonitor. Then how can i triggger intervalDidStart that i overwrited? Do i miss other details. Where can i use Mymonitor? Troubleshooting I have successfully shield apps using store.shield.applications = selection,applicationToken directly. Thanks for your reading and help!

I have posted a question on https://developer.apple.com/forums/thread/724437 The apple staff Kmart offerred me very helpful suggestions. However, i cannot leave a comment below it ( i am confused now) Following the apple staff Kmart's instuction, i submit a feedback and request TSI with. a sample Xcode project on (https://github.com/orcas1202/sample_for_TSI) However, TSI replied that it is still under investigation. So, i am here to find some support. Would you please take a look at the very sample project. Thanks in advance.