Dagger Android Support framework: Gradually study and use the guide (Step-By-Step Learning and USAGE for Dagger Android Support Framework)
Dagger Android Support framework: Gradually study and use guidelines
Overview:
Dagger is a dependent injection framework, which is developed and maintained by Google.It automatically generates a pre -configured code to help us manage complex dependencies easily.Dagger Android Support is an extension of the Dagger library, especially for the development of Android applications.This guide will gradually guide you to learn and use the Dagger Android Support framework and teach you how to configure related programming code.
Step 1: Configure Gradle Construction File
First, you need to add Dagger and Dagger Android Support library to the project's Gradle constructing files.Add the following code in your APP -level built.gradle file:
groovy
dependencies {
implementation 'com.google.dagger:dagger:2.x'
implementation 'com.google.dagger:dagger-android:2.x'
annotationProcessor 'com.google.dagger:dagger-compiler:2.x'
annotationProcessor 'com.google.dagger:dagger-android-processor:2.x'
}
Make sure to replace "2.x" to the latest version number.
Step 2: Configure the Application class
To use Dagger Android Support in the project, you need to create an Application class and use it as the entrance point of the main application.Your Application class should expand the Daggerapplication class and use the static method of the AndroidInjection class to build an application component.The following is an example:
public class MyApplication extends DaggerApplication {
@Override
protected AndroidInjector<? extends DaggerApplication> applicationInjector() {
return DaggerAppComponent.builder().create(this);
}
}
In the above example, DaggerappComPonent is the top component of your application.
Step 3: Configure the Activity class
When using Dagger Android Support, you need to configure some configuration on each Activity.First, create a module corresponding to your Activity, such as MainActivityModule.Then, use the @module annotation mark that the class, and use @Contributesandroidinjector annotation to assigns the Activity class to the module.The following is an example:
@Module
public abstract class MainActivityModule {
@ContributesAndroidInjector(modules = {MainActivityBindModule.class})
abstract MainActivity contributeMainActivity();
}
In the above example, the MainActivityBindModule is another module, which is equipped with the dependency item required by the MainActivity.
Step 4: Configure the AppComponent
Create an interface called AppComponent and mark it with @Component annotations.In this interface, using the @SINGLETON annotation marker domain to be the dependency item of Singleton, and use the @BindSInstance annotation to provide application instances.Then, use @androidInjectModule and the module configuration component you created in step 3.The following is an example:
@Singleton
@Component(modules = {AndroidSupportInjectionModule.class, MainActivityModule.class})
public interface AppComponent extends AndroidInjector<MyApplication> {
@Component.Builder
interface Builder {
@BindsInstance
Builder application(MyApplication application);
AppComponent build();
}
}
In the above example, AppComponent is the top component of the application.
Step 5: Use dependency injection
You have now completed the configuration of Dagger Android Support.In order to use dependency injection in Activity, you only need to call AndroidInjection.inject (this) in the OnCreate method of the Activity.The following is an example:
public class MainActivity extends AppCompatActivity {
@Inject
MyDependency myDependency;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
AndroidInjection.inject(this);
// Use myDependency object
// ...
}
}
In the above example, MyDependency is a dependency item you want to inject to MainActivity.
in conclusion:
By following the above steps, you can gradually learn and use the Dagger Android Support framework.This framework provides an elegant and powerful way to handle dependencies in Android applications.By using Dagger, you can better manage and organize code and improve the maintenance and scalability of applications.
