The technical principle analysis of the HILT Android framework (Analysis of Technical Principles of Hilt Android Framework)

Analysis of the technical principle of the Hilt Android framework HILT is a dependent injection framework launched by Google to simplify the development process of using dependencies in the Android application.This article will explore the technical principles of the Hilt Android framework and how to use the framework to achieve dependency injection. 1. What is dependency inject? Dependent injection is a design pattern for dependence between decoupled components.Under normal circumstances, we will directly create a dependent object in the constructor of the class, which will cause the class to be tightly coupled with its dependencies.The dependency injection is achieved by the creation and management of dependencies to the framework, thereby reducing coupling between categories. 2. Basic principles of the Hilt Android framework Hilt is built on the basis of Google's Dagger2. It simplifies the configuration process of Dagger2 and provides a more easy way to use to achieve dependency injection.HILT realizes the standards of dependence injection and can be customized according to the specific needs of the Android platform. HILT achieved dependence injection by generating compilation timing.It uses an annotation processor (APT) to generate the code required during the compilation period.HILT provides a set of annotations that developers can use these annotations to mark the classes, methods and fields that need to be relying on injects.During the compilation process, HILT will scan these annotations and generate the corresponding code. 3. The core annotation of HILT The following are some of the core annotations of HILT: -@HiltandroidApp: Used to mark the application class, indicating that this class is a HILT application. -@AndroidRypoint: Used to mark the Android components that need to be injected, such as Activity, Fragment, Service, etc. -@Inject: Used to mark the dependencies that need to be injected. -@Module: Modules for labeling to provide dependencies. -@Provides: Methods for labeling to provide dependencies. -@ViewModelinject: The ViewModel used for marking the need to be injected. 4. Example of HILT use First, add HILT dependencies to the project's Build. Gradle file: gradle dependencies { implementation 'com.google.dagger:hilt-android:2.35.1' kapt 'com.google.dagger:hilt-android-compiler:2.35.1' } Next, we need to create a HILT application class that uses @HILTANDROIDAPP annotations to mark: @HiltAndroidApp public class MyApp extends Application { // ... } Then, use the @Androidrypoint annotation in Activity that needs to be injected in an Activity: @AndroidEntryPoint public class MainActivity extends AppCompatActivity { @Inject MyDependency myDependency; // ... } Finally, we need to create a module to provide dependencies with @Module and @Provides annotations: @Module public class MyModule { @Provides MyDependency provideMyDependency() { return new MyDependency(); } } The above is the basic step of using the HILT framework for dependencies.By using the corresponding annotation, HILT will generate the required code during compilation and complete the dependent injection. Summarize: The HILT Android framework simplifies the process of using dependencies in the Android application.It is based on Dagger2 and generates dependency injection by generating compile timing.Developers only need to use relevant annotations to mark the class, methods and fields. HILT will automatically generate the necessary code to complete the injection of the dependent item.By using HILT, we can more conveniently implement the modular and test -available code, and reduce the coupling between classes.