标签：http username nic 最简 agg not 使用 on() proxy
dagger2是目前android端比较火的一款依赖注入框架，先来看下基本的用法吧：
首先提供module，类似于工厂：
@Module public class ApiServiceModule { private static final String ENDPOINT = ""; @Singleton @Provides public OkHttpClient providerOkHttpClient(){ OkHttpClient okHttpClient = new OkHttpClient(); okHttpClient.setConnectTimeout(60 * 1000, TimeUnit.MILLISECONDS); okHttpClient.setReadTimeout(60 * 1000, TimeUnit.MILLISECONDS); return okHttpClient; } @Singleton @Provides public RestAdapter providerRestAdapter(OkHttpClient okHttpClient){ RestAdapter.Builder builder = new RestAdapter.Builder(); builder.setClient(new OkClient(okHttpClient)) .setEndpoint(ENDPOINT); return builder.build(); } @Singleton @Provides public ApiService providerApiService(RestAdapter adapter){ return adapter.create(ApiService.class); } }
然后是component组件，用来连接module与需求方：
@Singleton @Component(modules = {AppModule.class , ApiServiceModule.class , AppServiceModule.class}) public interface AppComponent { Application getApplication(); ApiService getService(); User getUser(); }
在activity中使用：
public class MainActivity extends BaseActivity { private TextView tvName; @Inject MainPresenter mMainPresenter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tvName = findViewById(R.id.tvName); mMainPresenter.showUserName(); } @Override protected void setupActivityComponent(AppComponent appComponent) { DaggerMainActivityComponent.builder() .appComponent(appComponent) .mainActivityModule(new MainActivityModule(this)) .build().inject(this); } public void setTextName(String name){ tvName.setText(name); } }
使用是非常简单的，下面来看一下dagger2是如何做到依赖注入的吧：
首先会调到 DaggerMainActivityComponent.builder() ，我们会想到构建者模式，一起看下源码
public static Builder builder() { return new Builder(); }
Builder的构造函数中没有做任何处理，接下来看下.build方法：
public MainActivityComponent build() { if (mainActivityModule == null) { throw new IllegalStateException( MainActivityModule.class.getCanonicalName() + " must be set"); } if (appComponent == null) { throw new IllegalStateException(AppComponent.class.getCanonicalName() + " must be set"); } return new DaggerMainActivityComponent(this); }
new DaggerMainActivityComponent(this) 会初始化component，然后将builder传递进去，这也是建造者模式的一般写法，下面看下其中的构造函数会执行哪些方法呢
private void initialize(final Builder builder) { this.providerMainActivityProvider = DoubleCheck.provider( MainActivityModule_ProviderMainActivityFactory.create(builder.mainActivityModule)); this.getUserProvider = new com_winning_mvp_dagger2_retrofit_master_di_component_AppComponent_getUser( builder.appComponent); this.providerMainPresenterProvider = DoubleCheck.provider( MainActivityModule_ProviderMainPresenterFactory.create( builder.mainActivityModule, providerMainActivityProvider, getUserProvider)); }
下面我们来单独看一下这句
this.providerMainActivityProvider = DoubleCheck.provider( MainActivityModule_ProviderMainActivityFactory.create(builder.mainActivityModule));
走到MainActivityModule_ProviderMainActivityFactory中看一下：
public final class MainActivityModule_ProviderMainActivityFactory implements Factory<MainActivity> { private final MainActivityModule module; public MainActivityModule_ProviderMainActivityFactory(MainActivityModule module) { this.module = module; } @Override public MainActivity get() { return provideInstance(module); } public static MainActivity provideInstance(MainActivityModule module) { return proxyProviderMainActivity(module); } public static MainActivityModule_ProviderMainActivityFactory create(MainActivityModule module) { return new MainActivityModule_ProviderMainActivityFactory(module); } public static MainActivity proxyProviderMainActivity(MainActivityModule instance) { return Preconditions.checkNotNull( instance.providerMainActivity(), "Cannot return null from a non-@Nullable @Provides method"); } }
现在component中的属性都是有值的了，最后看下inject做了哪些操作：
public static void injectMMainPresenter(MainActivity instance, MainPresenter mMainPresenter) { instance.mMainPresenter = mMainPresenter; }
到这里依赖注入就已经完成了，这里只是分析了最简单的注入方式。
标签：http username nic 最简 agg not 使用 on() proxy
原文地址：https://www.cnblogs.com/sharkchao/p/10324606.html
