dagger2s is an IOC container framework (that is, what I do myself becomes a third party).
添加依赖：dependencies {
implementation 'com.google.dagger:dagger:2.x'
annotationProcessor 'com.google.dagger:dagger-compiler:2.x'
}
Module provides objects, Component is used to inject objects, and Class / Activity uses objects.
Source code example
Write entity class:
public class Student {
}
Write Module class:
@Module
public class StudentModule {
@Provides
public Student providerStudent () {
return new Student ();
}
}
Write component class:
@Component (modules = {StudentModule.class })
public interface StudentComponent {
Student providerStudent ();
}
Called in Activity:
public class MainActivity extends AppCompatActivity {
private static final String TAG = "DaggerActivity";
@Inject
Student student;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DaggerStudentComponent.create().injectMainActivity(this);
// StudentComponent studentComponent = DaggerStudentComponent.builder()
// .teacherModule(new TeacherModule())
// .build();
// teacherComponent.injectMainActivity(this);
Log.i(TAG, "onCreate: student="+student.hashCode());
}
Note:
A Model can be injected into multiple Components.
A Component can be injected into multiple Activity / Class.
An Activity / Class can only depend on one Component; if it depends on more than one, it is necessary to add dependencies and pass the dependencies in disguise.
Local singleton: Use @Singleton annotation; complex dependency delivery can use custom Singleton alias.
Global singleton: add dependency in custom Application for global use.
