一.先建立注解的模块
- 新建立annotation的module
- app中引入module
建立annotation_compiler
然后在annotation_compiler中的builder中修改
plugins {
id 'java-library'
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
//3.4+<
annotationProcessor 'com.google.auto.service:auto-service:1.0-rc4'
compileOnly 'com.google.auto.service:auto-service:1.0-rc3'
//3.4-
// implementation 'com.google.auto.service:auto-service:1.0-rc1'
implementation project(path: ':annotation')
}
sourceCompatibility = "7"
targetCompatibility = "7"
按照如上操作 app中引入annotation_complier模块
之后在app的builder中修改
annotationProcessor project(path: ':annotation_compiler')
之后在annotation_complier中建立annotationComplier文件 运用了apt技术 在编译到javac是时候就可以生成我们需要的文件 具体代码如下
package com.example.annotation_complier;
import com.example.annotation.BindView;
import com.google.auto.service.AutoService;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
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.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.TypeElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.type.TypeMirror;
import javax.tools.Diagnostic;
import javax.tools.JavaFileObject;
/**
* 注解处理器，用来生成代码的
* 使用前需要注册
*/
@AutoService(Processor.class)
public class AnnotationsCompiler extends AbstractProcessor {
//1.支持的版本
@Override
public SourceVersion getSupportedSourceVersion() {
return SourceVersion.latestSupported();
}
//2.能用来处理哪些注解
@Override
public Set<String> getSupportedAnnotationTypes() {
Set<String> types = new HashSet<>();
types.add(BindView.class.getCanonicalName());
// types.add(Override.class.getCanonicalName());
return types;
}
//3.定义一个用来生成APT目录下面的文件的对象
Filer filer;
@Override
public synchronized void init(ProcessingEnvironment processingEnvironment) {
super.init(processingEnvironment);
filer = processingEnvironment.getFiler();
}
/**
* 所有的坏事都在这个方法中实现
*
* @param set
* @param roundEnvironment
* @return
*/
@Override
public boolean process(Set<? extends TypeElement> set, RoundEnvironment roundEnvironment) {
processingEnv.getMessager().printMessage(Diagnostic.Kind.NOTE,"---------------"+set);
//获取APP中所有用到了BindView注解的对象
Set<? extends Element> elementsAnnotatedWith = roundEnvironment.getElementsAnnotatedWith(BindView.class);
// TypeElement//类
// ExecutableElement//方法
// VariableElement//属性
//开始对elementsAnnotatedWith进行分类
Map<String, List<VariableElement>> map = new HashMap<>();
for (Element element : elementsAnnotatedWith) {
VariableElement variableElement = (VariableElement) element;
String activityName = variableElement.getEnclosingElement().getSimpleName().toString();
Class aClass = variableElement.getEnclosingElement().getClass();
List<VariableElement> variableElements = map.get(activityName);
if (variableElements == null) {
variableElements = new ArrayList<>();
map.put(activityName, variableElements);
}
variableElements.add(variableElement);
}
//开始生成文件
// package com.example.butterknife_framework_demo;
// import com.example.butterknife_framework_demo.IBinder;
// public class MainActivity_ViewBinding implements IBinder<com.example.butterknife_framework_demo.MainActivity> {
// @Override
// public void bind(com.example.butterknife_framework_demo.MainActivity target) {
// target.textView = (android.widget.TextView) target.findViewById(2131165359);
//
// }
// }
if (map.size() > 0) {
Writer writer = null;
Iterator<String> iterator = map.keySet().iterator();
while (iterator.hasNext()) {
String activityName = iterator.next();
List<VariableElement> variableElements = map.get(activityName);
//得到包名
TypeElement enclosingElement = (TypeElement) variableElements.get(0).getEnclosingElement();
String packageName = processingEnv.getElementUtils().getPackageOf(enclosingElement).toString();
try {
JavaFileObject sourceFile = filer.createSourceFile(packageName + "." + activityName + "_ViewBinding");
writer = sourceFile.openWriter();
// package com.example.dn_butterknife;
writer.write("package " + packageName + ";\n");
// import com.example.dn_butterknife.IBinder;
writer.write("import " + packageName + ".IBinder;\n");
// public class MainActivity_ViewBinding implements IBinder<
// com.example.dn_butterknife.MainActivity>{
writer.write("public class " + activityName + "_ViewBinding implements IBinder<" +
packageName + "." + activityName + ">{\n");
// public void bind(com.example.dn_butterknife.MainActivity target) {
writer.write(" @Override\n" +
" public void bind(" + packageName + "." + activityName + " target){");
//target.tvText=(android.widget.TextView)target.findViewById(2131165325);
for (VariableElement variableElement : variableElements) {
//得到名字
String variableName = variableElement.getSimpleName().toString();
//得到ID
int id = variableElement.getAnnotation(BindView.class).value();
//得到类型
TypeMirror typeMirror = variableElement.asType();
writer.write("target." + variableName + "=(" + typeMirror + ")target.findViewById(" + id + ");\n");
}
writer.write("\n}}");
} catch (Exception e) {
e.printStackTrace();
} finally {
if (writer != null) {
try {
writer.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
return false;
}
}
注解处理器写完之后 对外使用建立一个窗口 建立JettButterknife文件
package com.example.zhujie;
import android.app.Activity;
public class JettButterknife {
public static void bind(Activity activity){
String name=activity.getClass().getName()+"_ViewBinding";
try{
Class<?> aClass=Class.forName(name);
IBinder iBinder=(IBinder)aClass.newInstance();
iBinder.bind(activity);
}catch(Exception e){
e.printStackTrace();
}
}
}
在MainActivity中如下使用
package com.example.zhujie;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import com.example.annotation.BindView;
public class MainActivity extends AppCompatActivity {
@BindView(R.id.textMv) // 绑定id
TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
JettButterknife.bind(this);
textView.setText("注解");
}
}
