android - Dagger 2 presenter injection returning null -

i attempting add dagger 2 android project. application have following screen

1. login extends base activity
2. navigation activity extends base activity
3. mw activity extents navigation activity

presenter injection working fine in login , navigation activity in mw activity return null

butter knife not working in mw activity working fine in other activities

following classes application class

public class abcapplication extends application {     applicationcomponent mapplicationcomponent;      @override     public void oncreate() {         super.oncreate();           mapplicationcomponent = daggerapplicationcomponent.builder()                 .applicationmodule(new applicationmodule(this))                 .build();         mapplicationcomponent.inject(this);     }      public static abcapplication get(context context) {         return (abcapplication) context.getapplicationcontext();     }      public applicationcomponent getcomponent() {         return mapplicationcomponent;     }      // needed replace component test specific 1     public void setcomponent(applicationcomponent applicationcomponent) {         mapplicationcomponent = applicationcomponent;     }   } 

base activity

public class baseactivity extends appcompatactivity {     private activitycomponent mactivitycomponent;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);     }       public activitycomponent activitycomponent() {         if (mactivitycomponent == null) {             mactivitycomponent = daggeractivitycomponent.builder()                     .activitymodule(new activitymodule(this))                     .applicationcomponent(abcapplication.get(this).getcomponent())                     .build();         }         return mactivitycomponent;     }  } 

navigation activity

public class navigationactivity extends baseactivity implements navigationview {      @inject     dataclient mdataclient;      @bind(r.id.drawer_layout)     protected drawerlayout mdrawerlayout;     @bind(r.id.navlist)     expandablelistview mexpandablelistview;      private actionbardrawertoggle mdrawertoggle;     private string mactivitytitle;     private expandablelistadapter mexpandablelistadapter;     private list<string> mexpandablelisttitle;     private map<string, list<string>> mexpandablelistdata;      private map<string, string> activitymap;      private int lastexpandedposition = -1;      @inject     navigationpresenter navigationpresenter;       @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_navigation);         activitycomponent().inject(this);         butterknife.bind(this);         navigationpresenter.attachview(this);           }     @override     protected void ondestroy() {     super.ondestroy();     navigationpresenter.detachview();     }         } 

mw activity

public class mwactivity extends navigationactivity implements mwview{     private mwpageradapter mmwpageradapter;       @inject     mwpresenter mwpresenter;      private viewpager mviewpager;       @override     protected void oncreate(bundle savedinstancestate) {          super.oncreate(savedinstancestate);         layoutinflater inflater = (layoutinflater) this.getsystemservice(context.layout_inflater_service);         drawerlayout mdrawer = (drawerlayout) findviewbyid(r.id.drawer_layout);          butterknife.bind(this);          mwpresenter.attachview(this);         mwpresenter.getmarketdata();         }      } 

logcat : fatal exception: main process: com.abc.xyz, pid: 21542

java.lang.runtimeexception: unable start activity componentinfo{com.abc.xyz/com.abc.trading.xyz.ui.main.mw.view.mwactivity}: java.lang.nullpointerexception @ android.app.activitythread.performlaunchactivity(activitythread.java:2318) @ android.app.activitythread.handlelaunchactivity(activitythread.java:2396)

@preactivity @component(dependencies = applicationcomponent.class, modules = activitymodule.class)      public interface activitycomponent {          void inject(loginactivity loginactivity);         void inject(navigationactivity navigationactivity);         void inject(mwactivity mwactivity);         void inject(mwtabfragment mwtabfragment);         void inject(mwdetailsactivity mwdetailsactivity);       } 

you have 2 issues regarding super- / sub types @ hand.

1. butterknife not support injection super types
2. dagger not support injection sub types

as pointed out, solve 2. need call inject in mwactivity, , use butterknife need use viewholder pattern within super class bind / inject fields, since inject mwactivity , not navigationactivity.