java - how to use injection between MVP layers in android? -

i have been using using dagger 2 in project lately,

the problem when try build project, presenter in login activity injected below is null,

and when try build project

presenter cannot provided without @inject constructor or @provides- or @produces-annotated method...

i don't understand have done wrong??, please me this,

thanks in advance.

here login activity, presenter here null, shows that, i've not injected properly

@inject loginpresenter presenter; protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_login);     injecthelper.getrootcomponent().injectpresenter(this);     presenter.setprogressbarvisiblity(view.invisible); } 

this presenter module

 @module  public class presentermodule {  private final loginactivity activity;  public presentermodule(loginactivity activity) {     this.activity = activity; }  @provides @singleton public loginactivity providesview() {      return activity; } }   @provides @singleton public loginpresenter providespresenter() {     return new loginpresenter(); } } 

this inject helper class

public class injecthelper {   private static rootcomponent srootcomponent;  static {     initmodules(); }  private static void initmodules() {     srootcomponent = getrootcomponentbuilder().build(); }  public static daggerrootcomponent.builder getrootcomponentbuilder() {     return daggerrootcomponent.builder(); }  public static rootcomponent getrootcomponent() {     if (srootcomponent == null) {         initmodules();     }     return srootcomponent; }  } 

this root component class

@singleton @component(modules = {      presentermodule.class }) public interface rootcomponent { void injectloginview(loginpresenter loginpresenter); } 

you need inform dagger views want use injection, in component. must change inject function code in component below:

    void inject(loginactivity activity); 

for showing dagger want, need use @dagger annotation not sending inject function in component file. did properly:

@inject loginpresenter presenter; 

dagger search variable of type loginpresenter in module , finds proper provider method using type.

what put in component argument "inject" function tells dagger view going injection in (not want inject)