本篇是apt文章的第二篇行贪，不太了解注解的童鞋可以先去第一篇學(xué)習(xí)一下注解漾稀，然后再看第二篇。
Android-Apt 注解處理器（一）
在學(xué)完注解以后 我們的注解處理器就能很快的上手了建瘫。
一崭捍、創(chuàng)建annotation 注解module ，注意：該module是java modle不是Android module
1.build.gradle配置
apply plugin: 'java-library'
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
}
sourceCompatibility = "1.7"
targetCompatibility = "1.7"
2.編寫(xiě)我們自己的注解
@Retention(RetentionPolicy.CLASS)
@Documented
@Target({ElementType.TYPE, ElementType.FIELD})
public @interface Bubble {
String name() default "123";
}
接口（根據(jù)實(shí)際情況設(shè)計(jì)）
public interface IBubble {
String getBubble();
}
二啰脚、創(chuàng)建annotationProcessor module 該module也是java module
1.build.gradle配置
apply plugin: 'java-library'
dependencies {
annotationProcessor 'com.google.auto.service:auto-service:1.0-rc4'
implementation 'com.google.auto.service:auto-service:1.0-rc4'
// 用于生成java類(lèi)
implementation 'com.squareup:javapoet:1.10.0'
// 依賴(lài)我們的注解module
implementation project(':lib-annotation')
}
sourceCompatibility = "1.8"
targetCompatibility = "1.8 "
2.AbstractProcessor 介紹
- void init(ProcessingEnvironment processingEnvironment) 殷蛇；
初始化、提供一些工具類(lèi) 。
2.Set<String> getSupportedAnnotationTypes()粒梦；
支持的注解類(lèi)型收擦，返回一個(gè)Set<String>,將我們要處理的注解全路徑添加進(jìn)去。
3.SourceVersion getSupportedSourceVersion()谍倦；
支持的編譯版本 可以指定位 SourceVersion.RELEASE_8、SourceVersion.RELEASE_7等等泪勒。
4.Set<String> getSupportedOptions()昼蛀；
獲取支持的選項(xiàng)、可以返回一下參數(shù)圆存。
5.boolean process(Set<? extends TypeElement> set, RoundEnvironment roundEnvironment);
這是我們要重點(diǎn)注意的方法叼旋，所有的注解處理以及我們要生成文件都會(huì)在這個(gè)方法中進(jìn)行。
3.創(chuàng)建一個(gè)BubbleProcessor 繼承AbstractProcessor沦辙，在init里面獲取到processingEnvironment提供的各種工具
@AutoService(Processor.class)
@SupportedAnnotationTypes("com.gzgxinfo.lib_annotation.Bubble")
@SupportedSourceVersion(SourceVersion.RELEASE_8)
public class BubbleProcessor extends AbstractProcessor {
private Filer mFiler;
private Messager mMessager;
private Elements mElements;
@Override
public synchronized void init(ProcessingEnvironment processingEnvironment) {
super.init(processingEnvironment);
mFiler = processingEnvironment.getFiler();
mMessager = processingEnvironment.getMessager();
mElements = processingEnvironment.getElementUtils();
mMessager.printMessage(Diagnostic.Kind.WARNING, "初始化");
}
@Override
public boolean process(Set<? extends TypeElement> set, RoundEnvironment roundEnvironment) {
mMessager.printMessage(Diagnostic.Kind.WARNING, "================================================");
return true;
}
}
4夫植、實(shí)現(xiàn)getSupportedAnnotationTypes 方法返回我們要處理的注解
@Override
public Set<String> getSupportedAnnotationTypes() {
Set<String> set = new LinkedHashSet<>();
set.add(Bubble.class.getCanonicalName());
mMessager.printMessage(Diagnostic.Kind.WARNING, Bubble.class.getName());
return set;
}
5.實(shí)現(xiàn)SourceVersion getSupportedSourceVersion()
@Override
public SourceVersion getSupportedSourceVersion() {
return SourceVersion.latestSupported();
}
6.實(shí)現(xiàn)Set<String> getSupportedOptions()
@Override
public Set<String> getSupportedOptions() {
Set<String> set = new LinkedHashSet<>();
set.add("BUBBLE");
return set;
}
在使用注解處理器的module的build.gradle中
defaultConfig {
applicationId "com.test.demo2"
minSdkVersion 16
targetSdkVersion 30
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
javaCompileOptions {
annotationProcessorOptions {
arguments = [BUBBLE: "我是option"]
}
}
}
在init中獲取到我們傳的參數(shù)
Map<String, String> options = processingEnvironment.getOptions();
mMessager.printMessage(Diagnostic.Kind.WARNING, "BUBBLE:"+options.get("BUBBLE"));
image.png
6.下面是最重要的方法，process
@Override
public boolean process(Set<? extends TypeElement> set, RoundEnvironment roundEnvironment) {
mMessager.printMessage(Diagnostic.Kind.WARNING, "================================================");
List<TypeElement> bubbles = new ArrayList<>();
Set<? extends Element> rootElements = roundEnvironment.getRootElements();
for (Element element : rootElements) {
// 不是類(lèi) 跳過(guò)
if (!(element instanceof TypeElement)) {
continue;
}
TypeElement typeElement = (TypeElement) element;
// 尋找到帶有Bubble 注解的類(lèi)
Bubble bubble = typeElement.getAnnotation(Bubble.class);
mMessager.printMessage(Diagnostic.Kind.WARNING, bubble + " " + (bubble == null));
if (bubble == null) {
continue;
}
mMessager.printMessage(Diagnostic.Kind.WARNING, "找到的類(lèi)********** " + (typeElement.getInterfaces().contains(IBubble.class)));
mMessager.printMessage(Diagnostic.Kind.WARNING, typeElement.getQualifiedName());
// 添加到集合
bubbles.add(typeElement);
}
for (TypeElement bubble : bubbles) {
mMessager.printMessage(Diagnostic.Kind.WARNING, "\n\n\n找到的所有類(lèi)**********: " + bubble);
}
if (!bubbles.isEmpty()) {
ClassName list = ClassName.get("java.util", "List");
ClassName arrayList = ClassName.get("java.util", "ArrayList");
ParameterizedTypeName typeName = ParameterizedTypeName.get(list, ClassName.get(IBubble.class));
// 創(chuàng)建一個(gè)IBubble 的List集合
FieldSpec fieldSpec = FieldSpec.builder(typeName, "mList", Modifier.PRIVATE)
.initializer("new $T()", arrayList)
.build();
// 創(chuàng)建個(gè)Field
FieldSpec str = FieldSpec.builder(String.class, "str", Modifier.PRIVATE)
.build();
// 把我們獲取到的類(lèi) 在我們要生成的java 類(lèi)中new出來(lái)
CodeBlock.Builder codeblock = CodeBlock.builder();
for (TypeElement bubble : bubbles) {
codeblock.addStatement("$N.add(new $T())", fieldSpec.name, ClassName.get(bubble));
}
// 創(chuàng)建方法
MethodSpec init = MethodSpec.constructorBuilder()
.addModifiers(Modifier.PUBLIC)
.addStatement("str=$S", "555555")
.addCode(codeblock.build())
.build();
// 創(chuàng)建一個(gè)方法 獲取到我們的集合
MethodSpec getList = MethodSpec.methodBuilder("getList")
.addModifiers(Modifier.PUBLIC)
.returns(typeName)
.addStatement("return $N", fieldSpec.name)
.build();
MethodSpec setList = MethodSpec.methodBuilder("setList")
.addParameter(ClassName.get(IBubble.class), "item")
.addModifiers(Modifier.PUBLIC)
.addStatement("$N.add(item)", fieldSpec.name)
.build();
// 創(chuàng)建一個(gè)類(lèi) 叫 BubbleClass
TypeSpec typeSpec = TypeSpec
.classBuilder("BubbleClass")
.addModifiers(Modifier.PUBLIC)
.addMethod(setList)
.addMethod(getList)
.addMethod(init)
.addField(fieldSpec)
.addField(str)
.build();
// 創(chuàng)建java文件 并寫(xiě)入
JavaFile file = JavaFile.builder("com.bubble.apt", typeSpec).build();
try {
file.writeTo(mFiler);
} catch (IOException e) {
e.printStackTrace();
}
}
return true;
}
三油讯、使用详民，創(chuàng)建app module
在build.gradle 中添加我們的注解處理器還有注解的依賴(lài)
implementation project(':lib-annotation')
annotationProcessor project(":lib-apt")
編寫(xiě)一個(gè)類(lèi) 實(shí)現(xiàn)IBubble 并使用我們的注解
@Bubble
public class Bubble1 implements IBubble {
@Override
public String getBubble() {
return "Bubble1";
}
}
編譯過(guò)后生成
image.png
到此 我們的注解處理器編寫(xiě)完成，特別注意的就是在使用我們的注解處理器的時(shí)候
要使用
annotationProcessor project(":lib-apt")
而不是
implementation project(":lib-apt")
下面貼出完整代碼
package com.bubble.lib_apt;
import com.bubble.lib_annotation.Bubble;
import com.bubble.lib_annotation.IBubble;
import com.google.auto.service.AutoService;
import com.squareup.javapoet.ClassName;
import com.squareup.javapoet.CodeBlock;
import com.squareup.javapoet.FieldSpec;
import com.squareup.javapoet.JavaFile;
import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.ParameterizedTypeName;
import com.squareup.javapoet.TypeSpec;
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
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.annotation.processing.SupportedAnnotationTypes;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.TypeElement;
import javax.lang.model.util.Elements;
import javax.tools.Diagnostic;
@AutoService(Processor.class)
@SupportedAnnotationTypes("com.bubbble.lib_annotation.Bubble")
@SupportedSourceVersion(SourceVersion.RELEASE_8)
public class BubbleProcessor extends AbstractProcessor {
private Filer mFiler;
private Messager mMessager;
private Elements mElements;
@Override
public synchronized void init(ProcessingEnvironment processingEnvironment) {
super.init(processingEnvironment);
mFiler = processingEnvironment.getFiler();
mMessager = processingEnvironment.getMessager();
mElements = processingEnvironment.getElementUtils();
mMessager.printMessage(Diagnostic.Kind.WARNING, "初始化");
Map<String, String> options = processingEnvironment.getOptions();
mMessager.printMessage(Diagnostic.Kind.WARNING, "BUBBLE:" + options.get("BUBBLE"));
}
@Override
public Set<String> getSupportedAnnotationTypes() {
Set<String> set = new LinkedHashSet<>();
set.add(Bubble.class.getCanonicalName());
mMessager.printMessage(Diagnostic.Kind.WARNING, Bubble.class.getCanonicalName());
return set;
}
@Override
public Set<String> getSupportedOptions() {
Set<String> set = new LinkedHashSet<>();
set.add("BUBBLE");
return set;
}
@Override
public SourceVersion getSupportedSourceVersion() {
return SourceVersion.latestSupported();
}
@Override
public boolean process(Set<? extends TypeElement> set, RoundEnvironment roundEnvironment) {
mMessager.printMessage(Diagnostic.Kind.WARNING, "================================================");
List<TypeElement> bubbles = new ArrayList<>();
Set<? extends Element> rootElements = roundEnvironment.getRootElements();
for (Element element : rootElements) {
// 不是類(lèi) 跳過(guò)
if (!(element instanceof TypeElement)) {
continue;
}
TypeElement typeElement = (TypeElement) element;
// 尋找到帶有Bubble 注解的類(lèi)
Bubble bubble = typeElement.getAnnotation(Bubble.class);
mMessager.printMessage(Diagnostic.Kind.WARNING, bubble + " " + (bubble == null));
if (bubble == null) {
continue;
}
mMessager.printMessage(Diagnostic.Kind.WARNING, "找到的類(lèi)********** " + (typeElement.getInterfaces().contains(IBubble.class)));
mMessager.printMessage(Diagnostic.Kind.WARNING, typeElement.getQualifiedName());
// 添加到集合
bubbles.add(typeElement);
}
for (TypeElement bubble : bubbles) {
mMessager.printMessage(Diagnostic.Kind.WARNING, "\n\n\n找到的所有類(lèi)**********: " + bubble);
}
if (!bubbles.isEmpty()) {
ClassName list = ClassName.get("java.util", "List");
ClassName arrayList = ClassName.get("java.util", "ArrayList");
ParameterizedTypeName typeName = ParameterizedTypeName.get(list, ClassName.get(IBubble.class));
// 創(chuàng)建一個(gè)IBubble 的List集合
FieldSpec fieldSpec = FieldSpec.builder(typeName, "mList", Modifier.PRIVATE)
.initializer("new $T()", arrayList)
.build();
// 創(chuàng)建個(gè)Field
FieldSpec str = FieldSpec.builder(String.class, "str", Modifier.PRIVATE)
.build();
// 把我們獲取到的類(lèi) 在我們要生成的java 類(lèi)中new出來(lái)
CodeBlock.Builder codeblock = CodeBlock.builder();
for (TypeElement bubble : bubbles) {
codeblock.addStatement("$N.add(new $T())", fieldSpec.name, ClassName.get(bubble));
}
// 創(chuàng)建方法
MethodSpec init = MethodSpec.constructorBuilder()
.addModifiers(Modifier.PUBLIC)
.addStatement("str=$S", "555555")
.addCode(codeblock.build())
.build();
// 創(chuàng)建一個(gè)方法 獲取到我們的集合
MethodSpec getList = MethodSpec.methodBuilder("getList")
.addModifiers(Modifier.PUBLIC)
.returns(typeName)
.addStatement("return $N", fieldSpec.name)
.build();
MethodSpec setList = MethodSpec.methodBuilder("setList")
.addParameter(ClassName.get(IBubble.class), "item")
.addModifiers(Modifier.PUBLIC)
.addStatement("$N.add(item)", fieldSpec.name)
.build();
// 創(chuàng)建一個(gè)類(lèi) 叫 BubbleClass
TypeSpec typeSpec = TypeSpec
.classBuilder("BubbleClass")
.addModifiers(Modifier.PUBLIC)
.addMethod(setList)
.addMethod(getList)
.addMethod(init)
.addField(fieldSpec)
.addField(str)
.build();
// 創(chuàng)建java文件 并寫(xiě)入
JavaFile file = JavaFile.builder("com.bubble.apt", typeSpec).build();
try {
file.writeTo(mFiler);
} catch (IOException e) {
e.printStackTrace();
}
}
return true;
}
}
