Dagger2

依赖

 implementation 'com.google.dagger:dagger:2.14.1'
    annotationProcessor 'com.google.dagger:dagger-compiler:2.14.1'

Component

package com.bwei.retiodit_rxjava_mvp.di.IComponent;

import com.bwei.retiodit_rxjava_mvp.di.IModule.MyModule;
import com.bwei.retiodit_rxjava_mvp.di.IModule.MyMoldeMoudule;
import com.bwei.retiodit_rxjava_mvp.di.IPresenter.Presenter;
import com.bwei.retiodit_rxjava_mvp.ui.activity.MainActivity;

import dagger.Component;

/**
 * Created by JackLee on 2018/9/5.
 */

public class MyComponent {
    @Component(modules = MyModule.class)
    public interface PresenterComponent{
        public void inject(MainActivity mainActivity);
    }
    @Component(modules = MyMoldeMoudule.class)
    public interface ModelComponent{
        public void inject(Presenter presenter);


    }
}

Module

package com.bwei.retiodit_rxjava_mvp.di.IModule;

import com.bwei.retiodit_rxjava_mvp.di.IPresenter.Presenter;

import dagger.Module;
import dagger.Provides;

@Module
public class MyModule {
    @Provides
    public Presenter getPresenter(){
        Presenter presenter = new Presenter();
        return presenter;
    }
}

mian

  @Inject
    Presenter presenter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        DaggerMyComponent_PresenterComponent.builder().myModule(new MyModule()).build().inject(this);
        presenter.attachView(this);
    }