In -depth exploration of Android dependence in injection library: analysis of frame principles and core concepts

In -depth exploration of Android dependence in injection library: analysis of frame principles and core concepts introduction: In Android development, dependency injection is a commonly used development model. Its purpose is to reduce code coupling and improve the maintenance of code and testability.Dependent injection makes the dependencies between objects managed by the external framework. Developers only need to pay attention to the realization of business logic without the need to manually create and manage the dependency relationship between objects.This article will deepen the Android dependencies to inject libraries to analyze its framework principles and core concepts. 1. The concept and role of dependence on the injection library Dependent injection library is a framework for providing dependent injection functions for Android development.It realizes the process of managing the dependence between objects and the process of injecting dependence into the object.The role of dependence in the injection library is decoupling and simplified code to improve the maintenance and testability of the code. Second, the principle of dependence in injection library The principle of relying on the implementation of the injection library is mainly divided into two steps: the creation and dependency injection of the object.During the creation of the object, the dependent injection library is instantly instantiated through the reflection mechanism, and the dependency relationship of the object is automatically analyzed during instantiation.During the dependency injection process, the dependent injection library is marked and injected by the injection and injection dependencies. 3. The core concept of dependence on the injecting library 1. Annotation: In the dependency injection library, the annotation is used to marked a class or method that needs to be dependent. 2. Injector: Injector is the core part of the injecting library, which is responsible for being injected into the required object.It determines the dependence relationship by analyzing the annotation and automatically completes the process of dependencies. 3. Component: The component is an object that needs to be carried out. It can be Android components such as Activity, Fragment, Service, etc., or it can be an ordinary POJO class. 4. Dependency: Dependent relationship refers to the situation where one object depends on the other object.In the dependency injection library, the dependencies are marked by the annotation, and the injection device automatically analyzes the dependent relationship based on these tags and is injected. 5. Lifecycle: In Android development, the life cycle of the object is an important concept.Relying on the injection library can manage the creation and destruction of the object according to the life cycle of the object. Fourth, sample code Below is a simple example code, which demonstrates how to use the dependency injection library for the dependency injection: First, add annotations to the classes that need to be relying in injection (for example @inject): public class ExampleClass { @Inject private DependencyClass dependency; // Other member variables and methods ... } Then create a injection device in the right place and call the injection method injecting: public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Create an injectioner Injector injector = new Injector(); // Get the object that needs to be injected ExampleClass example = new ExampleClass(); // Call the injection inject method injector.inject(example); // You can use the injected object example.doSomething(); } } Through the above code, the dependency injection will automatically inject the `DependencyClass` object into the` Dependency` member variable in the `ExampleClass` object. in conclusion: Through the exploration of this article, we understand the framework principles and core concepts of Android dependence on the injecting library.Relying on the use of injection libraries can help us simplify code, reduce coupling, improve maintenance and testability.In actual development, select a dependent injection library suitable for project needs, and reasonably use the concepts and technologies of dependency injection, which will greatly improve development efficiency and code quality.