objective c - iOS UIScrollView scrolling detection -

i'm developing kind of uitextview copy customizations. need implement selection cursors (see screenshot of original uitextview below)

as discovered debug view hierarchy apple developers draw these dots on separate window avoid clipping, , when uiscrollview starts dragging move these dots inside uitextview, when stops dragging move separate window. problem approach how can detect when of textview superview's uiscrollview , start/end scrolling? setting delegate each of uiscrollview-type superviews looks bad , bring lot of headache, cause need manage several delegates if needed (and detect there change). ideas?

/*  in viewdidload or ever create uitextview call :[self checkparentviewoftextview:textfield]; */  -(void)checkparentviewoftextview:(uitextview*)txv {     if ([txv.superview iskindofclass:[uiscrollview class]]) { // check if superview if uiscrollview         uiscrollview *superscroll =(uiscrollview*) txv.superview;         superscroll.delegate = self;// in order call delegate methods below         superscroll.tag = 5; // set tag access current scrollview @ these delegate methods     } } -(void)scrollviewdidscroll:(uiscrollview *)scrollview{     //any scrollview did begin scrolling     if (scrollview.tag == 5) {         //actions scrollview     } } -(void)scrollviewdidenddecelerating:(uiscrollview *)scrollview{     //any scrollview did end scrolling     if (scrollview.tag == 5) {         //actions scrollview     } }