Android dependence on the best practice of injection library: common questions and skills sharing

Android dependence on the best practice of injection library: common questions and skills sharing During the use of Android development, dependency injection is a common design mode that can simplify the writing of code, improve the readability of code, and help us better manage the dependence between code.In order to achieve dependencies injection, we can use many open source dependency injection libraries, such as Dagger, Butterknife, etc.However, in the process of using these libraries, we may encounter some common problems, and there are also some skills and best practices. This article will introduce these questions and answer these questions. Question 1: What is dependent injection? Dependent injection is a design mode that is used to manage the dependency relationship between code.By dependent injection, we can inject the required objects or dependencies into our class without creating them directly in the class.In this way, we can easily handle dependencies and make the code more flexible and testable. Question 2: Why use dependency injection library? Dependent injection libraries can help us better achieve and manage dependency injection.They provide some convenient annotations and tools that make it easier for us to use dependency injection in applications.At the same time, these libraries can also automatically handle the creation and injection of dependence, which reduces the workload of manually relying in injecting and improves development efficiency. Question 3: How to choose the appropriate dependency injection library? When choosing a dependence in injection library, we need to consider the following factors: -The learning curve: Some libraries may have a steeper learning curve, which requires more time and energy to learn and use.Therefore, we need to choose the right library according to the needs of the project and the experience of the team. -Function and performance: Different libraries provide different functions and performance, and we need to choose according to the needs of the project.Some libraries may provide more powerful functions, but it may bring some performance expenses, so weighing the house. -Se community support and documents: Choose a library with active communities and detailed documents, which can be more likely to help and solve when encountering problems. Question 4: How to use dependency injection libraries in the Android project? First of all, we need to add dependent items to the project's built.gradle file.For example, using Dagger to rely on the injection library: implementation 'com.google.dagger:dagger:2.x' annotationProcessor 'com.google.dagger:dagger-compiler:2.x' We can then use the annotation to mark the fields, construct functions or methods that need to be injected.For example, use Dagger injection in Activity: public class MyActivity extends AppCompatActivity { @Inject MyDependency myDependency; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); DaggerMyComponent.create().inject(this); } } In this example, we use the@inject` annotation to mark a field that needs to be injected. Question 5: How to deal with dependencies? The dependency injection library usually provides some mechanisms to handle dependencies.By using annotations to mark dependencies, we can control the creation and life cycle of the object.For example, using Dagger's `@Singleton` Activity Domain Note: @Singleton @Component(modules = {MyModule.class}) public interface MyComponent { MyDependency myDependency(); } In this example, we use the@s biography to mark the Component interface, and provide the implementation of the `MyDependency` in` MyModule`.In this way, Dagger will ensure that only one single instance is created and injected when needed. Question 6: How to test the unit? Relying in injection can facilitate unit testing, we can test the logic of the code by injecting the simulation object.For example, using the Mockito simulation object for unit testing: @RunWith(MockitoJUnitRunner.class) public class MyTestClass { @Mock MyDependency myDependency; @InjectMocks MyClass myClass; @Before public void setUp() { MockitoAnnotations.initMocks(this); } @Test public void testMethod() { // Use myDependency to test logic } } In this example, we use the@mock` annotation to mark the object that needs to be simulated `myDependency`, and then inject the simulation object into the need for testing through the` `@injectmocks` annotation. Summarize: This article introduces the best practice that depends on the injection library in Android, answers some common questions, and provides some examples and code examples.Through reasonable selection and use of dependencies into libraries, we can better manage the dependency relationship between code and improve the readability and testability of the code.It is hoped that these contents will help Android developers when using dependence into the library.