iOS Question [B4XPages] How to lock app after period of inactivity

Public Sub ResetIdleTimer
    Log("Reset idle timer")
End Sub

#if OBJC
@end 
@interface B4IViewController (nextResponder)
@end
@implementation B4IViewController (nextResponder)
- (UIResponder *)nextResponder {
    [[b4i_main new].bi raiseEvent:nil event:@"resetidletimer" params:nil];
    return [super nextResponder];
}
#End If

#If RELEASE
#if OBJC
@end 
@interface B4IViewController (nextResponder)
...

#End If
#end if

Public Sub ResetIdleTimer
    Log("Reset idle timer")
    'Note: actual name of timer object may vary
    idleTimer.Enabled = False
    'The Sleep(0) is to let the system process the Enabled event. May not be needed. @Erel may chime in on this
    Sleep(0)
    idleTimer.Enabled = True
End Sub

#import <UIKit/UIKit.h>
#import "iCore.h"

int main (int argc, char * argv[]) { @autoreleasepool { return UIApplicationMain (argc, argv, @"MyApplication", NSStringFromClass ([B4IAppDelegate class])); }}

Sub ResetIdleTimer
    oldTime = DateTime.Now
End Sub

#If OBJC
@end
@interface MyApplication: UIApplication
@end
@implementation MyApplication
double oldTime = 0;
double newTime = 0;
- (void) sendEvent: (UIEvent *) event
  {
  newTime = [[NSDate date] timeIntervalSince1970];
  if (newTime - oldTime > 30)
     {
     oldTime = newTime;
     [[b4i_main new].bi raiseEvent:nil event:@"resetidletimer" params:nil];     
     };
  [super sendEvent: event];
  }
#End If