Intent i = new Intent(UpdateService.this,Lock.class);
   i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
   this.startActivity(i); 

this.requestWindowFeature(Window.FEATURE_NO_TITLE);
 this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
Don't call setContentView() before requestFeature().

public booleanonKeyDown(int keyCode,KeyEvent event){
switch(keyCode){
caseKeyEvent.KEYCODE_HOME:return true;
caseKeyEvent.KEYCODE_BACK:return true;
caseKeyEvent.KEYCODE_CALL:return true;
caseKeyEvent.KEYCODE_SYM: return true;
caseKeyEvent.KEYCODE_VOLUME_DOWN: return true;
caseKeyEvent.KEYCODE_VOLUME_UP: return true;
caseKeyEvent.KEYCODE_STAR: return true;
}
returnsuper.onKeyDown(keyCode, event);
}

public voidonAttachedToWindow() {
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}

if (code ==KeyEvent.KEYCODE_HOME) {
 
  // If a system window has focus,then it doesn't make sense
  // right now to interact withapplications.
  WindowManager.LayoutParams attrs =win != null ? win.getAttrs() : null;
  if (attrs != null) {
  final int type = attrs.type;
  if (type ==WindowManager.LayoutParams.TYPE_KEYGUARD
   || type ==WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG) {
   // the "app" iskeyguard, so give it the key
   return false;
  }
  final int typeCount =WINDOW_TYPES_WHERE_HOME_DOESNT_WORK.length;
  for (int i=0; i<typeCount;i++) {
   if (type ==WINDOW_TYPES_WHERE_HOME_DOESNT_WORK[i]) {
   // don't do anything,but also don't pass it to the app
   return true;
   }
  }
  }