java - Can't catch clipboard event in a background service android -

i'm trying catch clipboardchanged event in background service

public class mainactivity extends actionbaractivity {       @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         intent = new intent(mainactivity.this, translateservice.class);         startservice(i);     } }   public class translateservice extends intentservice implements clipboardmanager.onprimaryclipchangedlistener {      public translateservice() {         super(null);     }      public translateservice(string name) {         super(name);         clipboardmanager manager = (clipboardmanager) getsystemservice(clipboard_service);         manager.addprimaryclipchangedlistener(this);     }        @override     protected void onhandleintent(intent intent) {      }      @override     public void onprimaryclipchanged() {         toast.maketext(this, "working", toast.length_long).show();     } } 

it should make toast "working" if event fired. tried create clipboardmanager , add listener in onhandleintent , didn't work either. ideas?

when default constructor called, not adding listener clipboardmanager.

i think meant use this(null) in default constructor instead of directly calling super(null).

public translateservice() {     this(null); }