《Android进阶之光》--Dagger2

青春须早为，岂能长少年。这篇文章主要讲述《Android进阶之光》--Dagger2相关的知识，希望能为你提供帮助。
No1：
Project的build.gradle文件添加

buildscript{ dependencies{ ...classpath ‘com.neenbedankt.gradle.plugins:android-apt:1.8‘ } }

Module:app的build.gradle添加

apply plugin: ‘com.neenbedankt.android-apt‘ ... dependencies{ ... apt ‘com.google.dagger:dagger-compiler:2.7‘ compile ‘com.google.dagger:dagger:2.7‘ }

No2：
@Inject、@Component

public class Watch{ @Inject public Watch(){ } public void work(){ } }

@Component public interface MainActivityComponent{ void inject(MainActivity activity); }

调用

public class MainActivity extends AppCompatActivity{ super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); DaggerMainActivityComponent.create().inject(this); //2 watch.work(); }

No3：
@Module、@Provides

@Inject Gson gson;

@Module public class GsonModule{ @Provides public Gson provideGson(){ return new Gson(); } }

@Component(modules = GsonModule.class) public interface MainActivityComponent{ void inject(MainActivity activity); }

调用

public class MainActivity extends AppCompatActivity{ @Inject Gson gson; @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); DaggerMainActivityComponent.create().inject(this); String jsonData = "https://www.songbingjia.com/android/{‘name‘:‘zhangwuji‘,‘age‘:20}"; Man man = gson.fromJson(jsonData,Man.class); } }

No4：
@Named、@Qualifier

@Module public class EngineModule{ @Provides @Named("Gasoline") public Engine provideGasoline(){ return new GasolineEngine(); } @Provides @Named("Diesel") public Engine provideDiesel(){ return new DieselEngine(); } }

调用

public class Car{ private Engine engine; @Inject public Car(@Named("Diesel") Engine engine){ this.engine = engine; } public String run(){ return engine.work(); } }

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@Qualifier @Retention(RUNTIME) public @interface GasoLine{ }@Qualifier @Retention(RUNTIME) public @interface Diesel{ }

@Module public class EngineModule{ @Provides @Gasonline public Engine provideGasoline(){ return new GasolineEngine(); } @Provides @Diesel public Engine provideDiesel(){ return new DieselEngine(); } }

public class Car{ private Engine engine; @Inject public Car(@Gasoline Engine engine){ this.engine = engine; } public String run(){ return engine.work(); } }

No5：
@Singleton、@Scope

@Inject Gson gson; @Inject Gson gson1;

@Module public class GsonModule{ @Singleton @Provides public Gson provideGson(){ return new Gson(); } }

@Singleton @Component(modules = GsonModule.class) public interface MainActivityComponent{ void inject(MainActiviy activity); }

调用

public class MainActivity extends AppCompatActivity{ private static final String TAG="Dagger2"; @Inject Gson gson; @Inject Gson gson1; @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); DaggerMainActivityComponent.create().inject(this); } }

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@Scope @Documented @Retention(RUNTIME) public @interface Singleton{}

@Scope @Rentention(RUNTIME) public @interface ApplicationScope{}

@Module public class GsonModule{ @ApplicationScope @Provides public Gson provideGson(){ return new Gson(); } }

@ApplicationScope @Component(modules=GsonModule.class) public interface ActivityComponent{ void inject(MainActivity activity); void inject(SecondActivity activity); }

public class App extends Application{ ActivityComponent activityComponent; @Override public void onCreate(){ super.onCreate(); activityComponent = DaggerActivityComponent.builder().build(); } public static App get(Context context){ return (App)context.getApplicationContext(); } ActivityComponent getActivityComponent(){ return activityComponent; } }

调用

public class MainActivity extends AppCompatActivity{ private static final String TAG="Dagger2"; private Button bt_jump; @Inject Gson gson; @Inject Gson gson1; @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); App.get(MainActivity.this).getActivityComponent().inject(this); onClick(); } private void onClick(){ bt_jump = (Button)findViewById(R.id.bt_jump); bt_jump.setOnClickListener(new View.OnClickListener(){ @Override public void onClick(View view){ Intent intent = new Intent(MainActivity.this,SecondActivity.class); startActivity(intent); } }); } }

No6：
@Component

public class Swordsman{ @Inject public Swordsman{ } public String fighting(){ return "欲为大树，莫与草争"; } }

@Module public class SwordsmanModule{ @Provides public Swordsman provideSwordsman(){ return new Swordsman(); } }@Component(modules = SwordsmanModule.class) public interface SwordsmanComponent{ Swordsman getSwordsman(); }

@ApplicationScope @Component(modules = GsonModule.class,dependencies = SwordsmanComponent.class) public interface ActivityComponent{ void inject(MainActivity activity); void inject(SecondActivity activity); }

public class App extends Application{ ActivityComponent activityComponent; @Override public void onCreate(){ super.onCreate(); activityComponent = DaggerActivityComponent.builder(); swordsmanComponent(DaggerSwordsmanComponent.builder().build()).build(); } public static App get(Context context){ return (App)context.getApplicationContext(); } ActivityComponent getActivityComponent(){ return activityComponent; } }

调用

public class SecondActivity extends AppCompatActivity{ @Inject Swordsman swordsman; @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); App.get(SecondActivity.this).getActivityComponent().inject(this); String sd = swordsman.fighting(; } }

No7：
懒加载：在@Inject的时候不初始化，而是使用的时候，调用get方法来获取实例

public class SecondActivity extends AppCompatActivity{ private static final String TAG="Dagger2"; @Inject Lazy< Swordsman> swordsmanLazy; @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); App.get(SecondActivity.this).getActivityComponent().inject(this); Swordsman swordsman = swordsmanLazy.get(); swordsman.fighting(); String sd1 = swordsman.fighting(); } }

【《Android进阶之光》--Dagger2】