Update app problem

If File.Exists(File.DirRootExternal,"dir/dir/..../setup.apk") Then

    'if there is a new apk, installs it
            
    Dim iIntent As Intent 
    iIntent.Initialize(iIntent.ACTION_VIEW,"file:///sdcard/dir/dir/..../setup.apk")
    iIntent.SetType("application/vnd.android.package-archive")

    StartActivity(iIntent) 
    
    'I have to wait for user click on the setup confirmation - There are other solutions??
    Sleep(SetupInterval * DateTime.TicksPerSecond)
            
    Dim in As Intent
    in.Initialize(in.ACTION_MAIN, "")
    in.SetComponent("package_name")
    
    'Problem
    'if user clicks on Cancel, and then clicks on Android Settings button (in tray), this row is executed but it doesn't work!!   
    StartActivity(in)
            
Else 
    'if there isn't an update, it starts the app

    Dim in As Intent
    in.Initialize(in.ACTION_MAIN, "")
    in.SetComponent("package_name")
            
    StartActivity(in)
            
End If

Sub Sleep(ticks As Int)

    DoEvents
   
    If ticks > 0 AND DateTime.TicksPerSecond > 0 Then
        Dim milliseconds As Int: milliseconds = 1000 / DateTime.TicksPerSecond * ticks
        Dim Lock1 As Lock
      
        Lock1.Initialize(True)
        Lock1.WaitFor(milliseconds)
        Lock1.Unlock
      
    End If
   
End Sub