java - Get Active Shell in SWT, even if the Shell is not on focus -

display.getactiveshell() seems consider shell active if it's focused. if @ moment application has focus means display.getactiveshell() returns null.

i need method tell me shell on focus on swt application, when swt application not on focus.

i've hacked piece of code together, although assertionexception:

public static shell getactiveshell() {     display display = display.getdefault();     shell result = display.getactiveshell();      if (result == null) {         shell[] shells = display.getshells();         (shell shell : shells) {             if (shell.getshells().length == 0) {                 if (result != null)                     throw new assertionexception();                 result = shell;             }         }     }      return result; } 

is there standard way approach issue other writing own method?

recently, had similar problem , though found solution in meanwhile i'd share mine future reference.

the shellactivationtracker adds display filter listens activate events , - if activated widget shell - remembers activated shell. can query (last) active shell if application not active/focused.

  class shellactivationtracker implements listener {     shell activeshell;      shellactivationtracker( display display ) {       activeshell = display.getactiveshell();       display.addfilter( swt.activate, );     }      @override     public void handleevent( event event ) {       if( event.widget instanceof shell ) {         activeshell = ( shell )event.widget;       }     }   }