java - How to enable back press to close nav drawer on fragment only -

i have implemented navigation drawer fragment hence know what's best way implement pressed feature fragments code needs go? i've used pressed code below doesn't work.

activity class

public class bakerloohdnactivity extends appcompatactivity {      //save our header or result     private drawer result = null;      private int getfactorcolor(int color, float factor) {         float[] hsv = new float[3];         color.colortohsv(color, hsv);         hsv[2] *= factor;         color = color.hsvtocolor(hsv);         return color;     }      @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_bakerloo_hdn);            localbroadcastmanager.getinstance(this).registerreceiver(onnotice, new intentfilter("backpressed_tag"));           final string actionbarcolor = "#b36305";          toolbar mtoolbar = (toolbar) findviewbyid(r.id.toolbar);         setsupportactionbar(mtoolbar);          if(getsupportactionbar()!=null) {             getsupportactionbar().setdisplayhomeasupenabled(true);             getsupportactionbar().setdisplayshowhomeenabled(false);             getsupportactionbar().settitle(html.fromhtml("<font color='#ffffff'>" + getresources().getstring(r.string.hdn) + "</font>"));              final drawable uparrow = contextcompat.getdrawable(this, r.drawable.abc_ic_ab_back_mtrl_am_alpha);             uparrow.setcolorfilter(getresources().getcolor(r.color.white), porterduff.mode.src_atop);             getsupportactionbar().sethomeasupindicator(uparrow);         }          if (build.version.sdk_int >= build.version_codes.lollipop) {             window window = getwindow();             window.addflags(windowmanager.layoutparams.flag_draws_system_bar_backgrounds);             getwindow().setstatusbarcolor(getfactorcolor(color.parsecolor(actionbarcolor), 0.8f));         }          // start of navigation drawer         accountheader headerresult = new accountheaderbuilder()             .withactivity(this)             .withcompactstyle(true)             .withheaderbackground(r.color.bakerloo)             .withprofileimagesvisible(false)             .withtextcolor(color.parsecolor("#ffffff"))             .withselectionlistenabled(false)              .addprofiles(                     new profiledraweritem().withname(getstring(r.string.hello)).withemail(getstring(r.string.world))             )             .build();          result = new drawerbuilder()             .withactivity(this)             .withaccountheader(headerresult)             .withtranslucentstatusbar(false)             .withactionbardrawertoggle(false)             .withselecteditem(-1)             .adddraweritems(                     new sectiondraweritem().withname(r.string.other_lines_nocaps).setdivider(false),                     new primarydraweritem().withname(r.string.hello_world).withidentifier(1).withcheckable(false)             )             .build();         // end of navigation drawer     }       @override     public void onbackpressed() {         if (result.isdraweropen()) {             result.closedrawer();         } else {             super.onbackpressed();         }          localbroadcastmanager.getinstance(context).sendbroadcast(new intent("backpressed_tag"));     } } 

fragment class

public class fragmentbakerloohdn extends android.support.v4.app.fragment {      public fragmentbakerloohdn() {         // required empty constructor     }      broadcastreceiver onnotice = new broadcastreceiver() {         @override         public void onreceive(context context, intent intent) {             // stuff when in activity pressed              headerresult.closedrawer();         }     };      // declaring navigation drawer     private accountheader headerresult = null;     private drawer result = null;       /**      * whether or not activity in two-pane mode, i.e. running on tablet      * device.      */     private boolean mtwopane;      @override     public void oncreate(bundle savedinstancestate) {         localbroadcastmanager.getinstance(getactivity()).registerreceiver(onnotice, new intentfilter("backpressed_tag"));          super.oncreate(savedinstancestate);     }      public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) {         view v = inflater.inflate(r.layout.fragment_bakerloo_hdn, container, false);           headerresult = new accountheaderbuilder()                 .withactivity(getactivity())                 .withcompactstyle(true)                 .withheaderbackground(r.color.bakerloo)                 .withprofileimagesvisible(false)                 .withtextcolor(color.parsecolor("#ffffff"))                 .withselectionlistenabled(false)                  .addprofiles(                         new profiledraweritem().withname(getstring(r.string.hdn)).withemail(getstring(r.string.hello_world))                 )                 .build();          result = new drawerbuilder()                 .withactivity(getactivity())                 .withaccountheader(headerresult)                 .withtranslucentstatusbar(false)                 .withactionbardrawertoggle(false)                 .withselecteditem(-1)                 .adddraweritems(                 new primarydraweritem().withname(r.string.hello_world).withidentifier(1).withcheckable(false)                 )                 .build();           super.oncreate(savedinstancestate);         return v;     }      @override     public void onactivitycreated(bundle savedinstancestate) {         view v = getview();          super.onactivitycreated(savedinstancestate);     } } 

there's no onbackpressed() in fragment. it's activity's method. can do, can make activity call fragment method when onbackpressed() called:

@override public void onbackpressed() {     if (!frag.onbackpressed() ) {         super.onbackpressed();     } } 

and fragment's onbackpressed() want , returntruewhen done anything, orfalse` otherwise, can call super's 1 in such case.