dagger2结合apt自动生成注入代码搭建mvp

其他 2019-01-28 03:04:34 阅读次数: 0

大家使用dagger2时候，通常要写一些注入代码，就算是再base类里面些， 当有新添加还有做修改。。其实倒也不麻烦，但是自动生成注入还是蛮爽的，像spring那样。。

本文分三部分来说吧。

  1. 第一部分是dagger2简单应用用一个mvp架构来做例子
  2. 第二部分是apt生成代码
  3. 第三部分是apt自动生成代码 再为dagger2提供注入。
    结合第第一个和第二个来看。 dagger需要我们手写Component，和初始化代码。 新建activity还是有点麻烦。用上apt只要一个注解，就会自动生成Component类 和初始化代码，使用dagger真正更简单。

首先时创建一个java工程，跟第二部分apt生成代码一样。创建2个注解，这里分别时用来标注activity和fragment的。

@Retention(RetentionPolicy.CLASS)
@Target(ElementType.TYPE)
public @interface ActivityInject {
}
@Retention(RetentionPolicy.CLASS)
@Target(ElementType.TYPE)
public @interface FragmentInject {
}

然后还是新建一个java工程，用来做注解处理器和其他类
总共2个核心类。一个时注解处理器，一个辅助文件生成的。
首先看注解处理器、

package com.spc;

import com.google.auto.service.AutoService;

import java.lang.annotation.Annotation;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.Filer;
import javax.annotation.processing.Messager;
import javax.annotation.processing.ProcessingEnvironment;
import javax.annotation.processing.Processor;
import javax.annotation.processing.RoundEnvironment;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.TypeElement;
import javax.lang.model.util.Elements;
import javax.tools.Diagnostic;


/**
 * Created by spc on 17/6/6.
 */
@AutoService(Processor.class)
public class ActivityInjectProcesser extends AbstractProcessor {
    private Filer mFiler; //文件相关的辅助类
    private Elements mElementUtils; //元素相关的辅助类  许多元素
    private Messager mMessager; //日志相关的辅助类

    private Map<String, AnnotatedClass> mAnnotatedClassMap;

    @Override
    public synchronized void init(ProcessingEnvironment processingEnv) {
        super.init(processingEnv);
        mFiler = processingEnv.getFiler();
        mElementUtils = processingEnv.getElementUtils();
        mMessager = processingEnv.getMessager();
        mAnnotatedClassMap = new TreeMap<>();
    }

    //扫描到注解会执行这里
    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        mAnnotatedClassMap.clear();

        try {
            processActivityCheck(roundEnv);
            processFragmentCheck(roundEnv);
        } catch (Exception e) {
            e.printStackTrace();
            error(e.getMessage());
        }

        for (AnnotatedClass annotatedClass : mAnnotatedClassMap.values()) {
            try {
                Class fgAnType = Class.forName(TypeUtil.ANNOTATION_FRAGMENT_PATH);
                Class acAnType = Class.forName(TypeUtil.ANNOTATION_PATH);
                if (annotatedClass.getmTypeElement().getAnnotation(fgAnType) != null) {
                    annotatedClass.generateFragmentDaggerFile().writeTo(mFiler);
                    annotatedClass.generateFragmentFile().writeTo(mFiler);
                } else if (annotatedClass.getmTypeElement().getAnnotation(acAnType) != null){
                    annotatedClass.generateActivityDaggerFile().writeTo(mFiler);
                    annotatedClass.generateActivityFile().writeTo(mFiler);
                }


            } catch (Exception e) {
                error("Generate file failed, reason: %s", e.getMessage());
            }
        }
        return true;
    }


    private void processActivityCheck(RoundEnvironment roundEnv) throws IllegalArgumentException, ClassNotFoundException {
        //check ruleslass forName(String className
        for (Element element : roundEnv.getElementsAnnotatedWith((Class<? extends Annotation>) Class.forName(TypeUtil.ANNOTATION_PATH))) {
            if (element.getKind() == ElementKind.CLASS) {
                getAnnotatedClass(element);
            } else
                error("ActivityInject only can use  in ElementKind.CLASS");
        }
    }

    private void processFragmentCheck(RoundEnvironment roundEnv) throws IllegalArgumentException, ClassNotFoundException {
        //check ruleslass forName(String className
        for (Element element : roundEnv.getElementsAnnotatedWith((Class<? extends Annotation>) Class.forName(TypeUtil.ANNOTATION_FRAGMENT_PATH))) {
            if (element.getKind() == ElementKind.CLASS) {
                getAnnotatedClass(element);
            } else
                error("FragmentInject only can use  in ElementKind.CLASS");
        }
    }

    private AnnotatedClass getAnnotatedClass(Element element) {
        // tipe . can not use chines  so  ....
        // get TypeElement  element is class's --->class  TypeElement typeElement = (TypeElement) element
        //  get TypeElement  element is method's ---> TypeElement typeElement = (TypeElement) element.getEnclosingElement();
        TypeElement typeElement = (TypeElement) element;
        String fullName = typeElement.getQualifiedName().toString();
        AnnotatedClass annotatedClass = mAnnotatedClassMap.get(fullName);
        if (annotatedClass == null) {
            annotatedClass = new AnnotatedClass(typeElement, mElementUtils, mMessager);
            mAnnotatedClassMap.put(fullName, annotatedClass);
        }
        return annotatedClass;
    }


    @Override
    public SourceVersion getSupportedSourceVersion() {
        return SourceVersion.latestSupported();
    }

    //这个方法，返回要处理什么注解 的一个set集合
    @Override
    public Set<String> getSupportedAnnotationTypes() {
        Set<String> types = new LinkedHashSet<>();
        types.add(TypeUtil.ANNOTATION_PATH);
        types.add(TypeUtil.ANNOTATION_FRAGMENT_PATH);
        return types;
    }

    private void error(String msg, Object... args) {
        mMessager.printMessage(Diagnostic.Kind.ERROR, String.format(msg, args));
    }

    private void log(String msg, Object... args) {
        mMessager.printMessage(Diagnostic.Kind.NOTE, String.format(msg, args));
    }
}

然后编译时候生成类的 代码

package com.spc;


import com.spc.TypeUtil;
import com.squareup.javapoet.AnnotationSpec;
import com.squareup.javapoet.ClassName;
import com.squareup.javapoet.JavaFile;
import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.TypeName;
import com.squareup.javapoet.TypeSpec;

import javax.annotation.processing.Messager;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.TypeElement;
import javax.lang.model.util.Elements;
import javax.tools.Diagnostic;


/**
 * Created by spc on 17/6/6.
 */
public class AnnotatedClass {

    private TypeElement mTypeElement;//activity  //fragmemt
    private Elements mElements;
    private Messager mMessager;//日志打印

    public AnnotatedClass(TypeElement typeElement, Elements elements, Messager messager) {
        mTypeElement = typeElement;
        mElements = elements;
        this.mMessager = messager;
    }


    public JavaFile generateActivityFile() {
        // build inject method
        MethodSpec.Builder injectMethod = MethodSpec.methodBuilder(TypeUtil.METHOD_NAME)
                .addModifiers(Modifier.PUBLIC)
                .addParameter(TypeName.get(mTypeElement.asType()), "activity", Modifier.FINAL);
        injectMethod.addStatement(TypeUtil.MAIN_ACTIVITY_PATH + ".$L.builder()\n.$L($L)\n" +
                        ".$L(new $L(activity))\n" +
                        ".build()\n.$L(activity)",
                "Dagger" + mTypeElement.getSimpleName() + "$$Component",
                TypeUtil.APP_Component_Name,
                TypeUtil.APPCOMPONENT_PROVIDE_PATH,
                TypeUtil.APP_ActivityModule_Name,
                TypeUtil.ACTIVITY_MODULE_PATH,
                TypeUtil.METHOD_NAME);

        //generaClass
        TypeSpec injectClass = TypeSpec.classBuilder(mTypeElement.getSimpleName() + "$$InjectActivity")
                .addModifiers(Modifier.PUBLIC)
//                .addSuperinterface(ParameterizedTypeName.get(TypeUtil.INJET_NAME, TypeName.get(mTypeElement.asType())))
                .addMethod(injectMethod.build())
                .build();
        String packgeName = mElements.getPackageOf(mTypeElement).getQualifiedName().toString();
        return JavaFile.builder(packgeName, injectClass).build();
    }

    public JavaFile generateActivityDaggerFile() {
        MethodSpec.Builder injectMethod = MethodSpec.methodBuilder(TypeUtil.METHOD_NAME)
                .addModifiers(Modifier.PUBLIC, Modifier.ABSTRACT)
                .addParameter(TypeName.get(mTypeElement.asType()), "activity");
        //generaClass
        TypeSpec injectClass = TypeSpec.interfaceBuilder(mTypeElement.getSimpleName() + "$$Component")
                .addModifiers(Modifier.PUBLIC)
                .addAnnotation(TypeUtil.ACTIVITY_SCOPE_CLASSNAME)
                .addAnnotation(AnnotationSpec.builder(ClassName.get("dagger", "Component"))
                        .addMember("dependencies", "$L", TypeUtil.APP_COMPONENT_PATH + ".class")
                        .addMember("modules", "$L", TypeUtil.ACTIVITY_MODULE_PATH + ".class")
                        .build())
                .addMethod(injectMethod.build())
                .build();
        gradleLog("---->dagger   " + mTypeElement.getSimpleName() + "    Component   buuild success");
        String packgeName = mElements.getPackageOf(mTypeElement).getQualifiedName().toString();
        return JavaFile.builder(packgeName, injectClass).build();
    }




    public JavaFile generateFragmentFile() {
        // build inject method
        MethodSpec.Builder injectMethod = MethodSpec.methodBuilder(TypeUtil.METHOD_NAME)
                .addModifiers(Modifier.PUBLIC)
                .addParameter(TypeName.get(mTypeElement.asType()), "fragment", Modifier.FINAL);
        injectMethod.addStatement(TypeUtil.MAIN_FRAGMENT_PATH + ".$L.builder()\n.$L($L)\n" +
                        ".$L(new $L(fragment))\n" +
                        ".build()\n.$L(fragment)",
                "Dagger" + mTypeElement.getSimpleName() + "$$Component",
                TypeUtil.APP_Component_Name,
                TypeUtil.APPCOMPONENT_PROVIDE_PATH,
                TypeUtil.APP_FragmentModule_Name,
                TypeUtil.FRAGMENT_MODULE_PATH,
                TypeUtil.METHOD_NAME);

        //generaClass
        TypeSpec injectClass = TypeSpec.classBuilder(mTypeElement.getSimpleName() + "$$InjectFragment")
                .addModifiers(Modifier.PUBLIC)
                .addMethod(injectMethod.build())
                .build();
        String packgeName = mElements.getPackageOf(mTypeElement).getQualifiedName().toString();
        return JavaFile.builder(packgeName, injectClass).build();
    }

    public JavaFile generateFragmentDaggerFile() {
        MethodSpec.Builder injectMethod = MethodSpec.methodBuilder(TypeUtil.METHOD_NAME)
                .addModifiers(Modifier.PUBLIC, Modifier.ABSTRACT)
                .addParameter(TypeName.get(mTypeElement.asType()), "fragment");
        //generaClass
        TypeSpec injectClass = TypeSpec.interfaceBuilder(mTypeElement.getSimpleName() + "$$Component")
                .addModifiers(Modifier.PUBLIC)
                .addAnnotation(TypeUtil.FRAGMENT_SCOPE_CLASSNAME)
                .addAnnotation(AnnotationSpec.builder(ClassName.get("dagger", "Component"))
                        .addMember("dependencies", "$L", TypeUtil.APP_COMPONENT_PATH + ".class")
                        .addMember("modules", "$L", TypeUtil.FRAGMENT_MODULE_PATH + ".class")
                        .build())
                .addMethod(injectMethod.build())
                .build();
        gradleLog("---->dagger   " + mTypeElement.getSimpleName() + "    Component   buuild success");
        String packgeName = mElements.getPackageOf(mTypeElement).getQualifiedName().toString();
        return JavaFile.builder(packgeName, injectClass).build();
    }

    private void gradleLog(String msg, Object... args) {
        mMessager.printMessage(Diagnostic.Kind.NOTE, String.format(msg, args));
    }

    public TypeElement getmTypeElement() {
        return mTypeElement;
    }
}

还有一个常量文件

public class TypeUtil {
    /**
     * ?????
     */
    public static final String MAIN_PROJECT_PACKAGE_NAME = "com.spc.spc.myapplication";
    /**
     * activity ????
     */
    public static final String MAIN_ACTIVITY_PATH = MAIN_PROJECT_PACKAGE_NAME + ".ui.activity";
    public static final String MAIN_FRAGMENT_PATH = MAIN_PROJECT_PACKAGE_NAME + ".ui.fragment";

    /**
     * app???component ???? ????  ??
     */
    public static final String APP_Component_Name = "appcomponent";
    public static final String APP_Component_Name_Capital = "Appcomponent";
    public static final String APP_COMPONENT_PATH = MAIN_PROJECT_PACKAGE_NAME + ".di.component." + APP_Component_Name_Capital;
    /**
     * activity?Module ???? ????
     */
    public static final String APP_ActivityModule_Name = "activityModule";
    public static final String APP_ActivityModule_Name_Capital = "ActivityModule";
    public static final String ACTIVITY_MODULE_PATH = MAIN_PROJECT_PACKAGE_NAME + ".di.module." + APP_ActivityModule_Name_Capital;

    /**
     * fragment module
     */
    public static final String APP_FragmentModule_Name = "fragmentModule";
    public static final String APP_FragmentModule_Name_Capital = "FragmentModule";
    public static final String FRAGMENT_MODULE_PATH = MAIN_PROJECT_PACKAGE_NAME + ".di.module." + APP_FragmentModule_Name_Capital;


    /**
     * ??application????App???  Component???
     */
    public static final String APPCOMPONENT_PROVIDE_PATH = MAIN_PROJECT_PACKAGE_NAME + ".base.MyApplication.getInst().getAppComponent()";

    /**
     * Scope ???
     */
    public static final ClassName ACTIVITY_SCOPE_CLASSNAME = ClassName.get(MAIN_PROJECT_PACKAGE_NAME + ".di.scope", "ActivityScope");
    public static final ClassName FRAGMENT_SCOPE_CLASSNAME = ClassName.get(MAIN_PROJECT_PACKAGE_NAME + ".di.scope", "FragmentScope");

    /**
     * ???????
     */
    public static final String METHOD_NAME = "inject";

    public static final String ANNOTATION_PATH = "com.spc.ActivityInject";
    public static final String ANNOTATION_FRAGMENT_PATH = "com.spc.FragmentInject";
//    public static final ClassName INJET_NAME = ClassName.get("com.example.injectlib", "Inject");
}

还差最后一个就是注解的初始化代码

package com.spc.spc.myapplication.di.aptinject;

import android.support.v4.util.ArrayMap;
import android.support.v7.app.AppCompatActivity;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;


public class InjectActivity {
    private static final ArrayMap<String, Object> injectMap = new ArrayMap<>();

    public static void inject(AppCompatActivity activity) {
        String className = activity.getClass().getName();
        try {
            Object inject = injectMap.get(className);

            if (inject == null) {
                Class<?> aClass = Class.forName(className + "$$InjectActivity");
                inject =  aClass.newInstance();
                injectMap.put(className, inject);
            }
            Method m1 = inject.getClass().getDeclaredMethod("inject",activity.getClass());
            m1.invoke(inject,activity);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }
}

这样在activity上标注一个@ActivityInject 就可以完成dagger的初始化了。
在baseactivity里面初始化就好

看使用

public abstract class BaseMVPActivity<P extends BasePresenter> extends BaseActivity implements BaseMvpViewInterface {

    @Inject
    protected P mvpPresenter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        InjectActivity.inject(this);
        mvpPresenter.attachView(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mvpPresenter != null) {
            mvpPresenter.detachView();
        }
    }
}
@ActivityInject//apt注解注入。不需要手写
public class MainActivity extends BaseMVPActivity<MainPresenter> implements MainacView {

   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
           }

就这样。dagger2不需要component和初始化，一个注解就完成了。
fragment的 一样。在注解处理器里面，处理了fragment的状况

demo地址https://github.com/836154942/dagger2_mvpDemo

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