Android使用AOP

莫问天涯路几重,轻衫侧帽且从容。这篇文章主要讲述Android使用AOP相关的知识,希望能为你提供帮助。
这里不讲aop的概念,网上资料很多,这里只讲如何配置aop和自定义plugin。
1、使用场景
在android中,有些业务是公共的,例如:登录判断、获取权限、网络判断等一些公用的业务逻辑,这些都可以使用aop编程。在未使用aop的时候,登录可能会像下面那样写:

工具类:ASUtils /** * 如果未登录,返回true,并且跳转到登录页 * * @return boolean */ public static boolean isUnLogined() { if (AppContext.component().userManager().hasUser()) { // 是否已登录 return false; } ToastHelper.showMessage(R.string.login_required); IntentUtils.actionWeChatLogin(AppManager.currentActivity(), IReturnType.Mine); return true; }Activity或者Fragment调用: private void toUserPage() { if (ASUtils.isUnLogined()) return; IntentUtils.startActivity(getActivity(), UserActivity.class); }

【Android使用AOP】而使用Aop后,编码会变得简洁很多,只需要在方法上添加@LoginFilter即可:
@LoginIntercept private void toUserPage() { IntentUtils.startActivity(getActivity(), UserActivity.class); }

2、配置Aspectj
在module或者app中配置Aspectj会比较麻烦,目前有人已经在github开源了支持Android的Aspectj库(Hugo),这里不讲它的使用,具体可以去github查看使用方法。
首先,在根目录build.gradle添加aspectj的支持:
buildscript {repositories { google() jcenter() } dependencies { classpath ' com.android.tools.build:gradle:3.1.0' classpath ' org.aspectj:aspectjtools:1.8.13' // add classpath ' org.aspectj:aspectjrt:1.8.13' // add // NOTE: Do not place your application dependencies here; they belong // in the individual module build.gradle files } }

其次,在app目录下的build.gradle添加支持
import org.aspectj.bridge.IMessage import org.aspectj.bridge.MessageHandler import org.aspectj.tools.ajc.Mainfinal def log = project.logger final def variants = project.android.applicationVariants //在构建工程时,执行编织 variants.all { variant -> if (!variant.buildType.isDebuggable()) { log.debug(" Skipping non-debuggable build type ' ${variant.buildType.name}' ." ) return; }javaCompile javaCompile = variant.javaCompile javaCompile.doLast { String[] args = [" -showWeaveInfo" , " -1.8" , " -inpath" , javaCompile.destinationDir.toString(), " -aspectpath" , javaCompile.classpath.asPath, " -d" , javaCompile.destinationDir.toString(), " -classpath" , javaCompile.classpath.asPath, " -bootclasspath" , project.android.bootClasspath.join(File.pathSeparator)] log.debug " ajc args: " + Arrays.toString(args)MessageHandler handler = new MessageHandler(true); new Main().run(args, handler); for (IMessage message : handler.getMessages(null, true)) { switch (message.getKind()) { case IMessage.ABORT: case IMessage.ERROR: case IMessage.FAIL: log.error message.message, message.thrown break; case IMessage.WARNING: log.warn message.message, message.thrown break; case IMessage.INFO: log.info message.message, message.thrown break; case IMessage.DEBUG: log.debug message.message, message.thrown break; } } } } dependencies { implementation ' org.aspectj:aspectjrt:1.8.13' }

上面log是为了方便在build project的时候查看相关日志,定位是否build failed的信息。如果需要单独一个module来做aop的lib话,在module下build.gradle添加
import org.aspectj.bridge.IMessage import org.aspectj.bridge.MessageHandler import org.aspectj.tools.ajc.Main project.android.libraryVariants.all { variant -> JavaCompile javaCompile = variant.javaCompile javaCompile.doLast { String[] args = [" -showWeaveInfo" , " -1.8" , " -inpath" , javaCompile.destinationDir.toString(), " -aspectpath" , javaCompile.classpath.asPath, " -d" , javaCompile.destinationDir.toString(), " -classpath" , javaCompile.classpath.asPath, " -bootclasspath" , project.android.bootClasspath.join( File.pathSeparator)]MessageHandler handler = new MessageHandler(true); new Main().run(args, handler)def log = project.logger for (IMessage message : handler.getMessages(null, true)) { switch (message.getKind()) { case IMessage.ABORT: case IMessage.ERROR: case IMessage.FAIL: log.error message.message, message.thrown break; case IMessage.WARNING: case IMessage.INFO: log.info message.message, message.thrown break; case IMessage.DEBUG: log.debug message.message, message.thrown break; } } } } dependencies { implementation ' org.aspectj:aspectjrt:1.8.13' }

你会发现,app和module的配置都差不多,唯一的区别在于一个是applicationVariants
,一个是libraryVariants,其它都是一样。Aspectj配置已经完成,可以Sync Now是否Success。
参数说明
| 参数 | 说明 |
|:----|:----|
| -showWeaveInfo | 输入AJC 编译信息 |
| -1.8 | 声明AJC 支持AspectJ 1.5 版本 |
| -inpath | 需要编译的.class 文件目录(包含Jar文件) |
| -classpath | 指定哪里可以找到用户的class 文件 |
| -aspectpath | aspect 编译的Jar文件或者目录路径 |
| -d | 编译后输出的目录 |
| -bootclasspath | 编译时修改本地的bootcloasspath |
3、定义登录aop
添加LoginFilter的注解类
package com.fomin.aop.login.aspect; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; /** * Created by Fomin on 2018/8/30. */ @SuppressWarnings(" CheckStyle" ) @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) public @interface LoginIntercept { int actionDefine() default 0; }

注解相关的AspectJ的实现类
package com.fomin.aop.login.aspect; import android.content.Context; import android.util.Log; import com.fomin.aop.execption.AnnotationException; import com.fomin.aop.execption.NoInitException; import com.fomin.aop.login.core.ILogin; import com.fomin.aop.login.core.LoginAssistant; import org.aspectj.lang.ProceedingJoinPoint; import org.aspectj.lang.Signature; import org.aspectj.lang.annotation.Around; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Pointcut; import org.aspectj.lang.reflect.MethodSignature; /** * Created by Fomin on 2018/8/30. */ @Aspect public class LoginInterceptAspect {private static final String TAG = " LoginInterceptAspect" ; @Pointcut(" execution(@com.fomin.aop.login.aspect.LoginIntercept private * *..*.*(..))" )//这里使用private是因为方法中全部是private,也可以去除 public void loginFilter() { }@SuppressWarnings(" CheckStyle" ) @Around(" loginFilter()" ) public void aroundLoginPoint(ProceedingJoinPoint joinPoint) throws Throwable { ILogin login = LoginSDK.getInstance().getLogin(); if (login == null) { throw new NoInitException(" LoginSDK没有初始化!" ); }Signature signature = joinPoint.getSignature(); if (!(signature instanceof MethodSignature)) { throw new AnnotationException(" LoginIntercept注解只能用于方法上" ); }MethodSignature methodSignature = (MethodSignature) signature; Log.d(" Aspect" , String.valueOf(methodSignature.getName())); Log.d(" Aspect" , String.valueOf(methodSignature.getMethod() == null)); LoginIntercept loginIntercept = methodSignature.getMethod().getAnnotation(LoginIntercept.class); if (loginIntercept== null) { return; } Context param = LoginSDK.getInstance().getContext(); if (login.isLogin(param)) { joinPoint.proceed(); } else { login.login(param, loginFilter.actionDefine()); } } }

注意:在LoginFilterAspect 类中如果有用到Context,可直接使用joinPoint.getTarget()类型转换成Context,这里是由于项目使用了databinding,部分getTarget()获取到的值不能强转为Context,所以这里用的MyApplication获取的Context。
ILogin接口:
ILogin:接口 package com.huaying.aop.login.core; import android.content.Context; /** * Created by Fomin on 2018/8/29. */ public interface ILogin {/** * 登录事件接收 * @param context Context * @param actionDefine 登录操作 */ void login(Context context, int actionDefine); /** * 判断是否登录 * @param context Context * @return */ boolean isLogin(Context context); }

LoginSDK 类:
package com.huaying.aop.login.core; import android.content.Context; /** * Created by Fomin on 2018/8/30. */ public class LoginSDK { private static LoginSDK instance; private LoginSDK() { }public static LoginSDK getInstance() { if (instance == null) { synchronized (LoginSDK.class) { if (instance == null) { instance = new LoginSDK(); } } } return instance; }private ILogin login; private Context context; /** * 初始化 * * @param context Context * @param iLogin登录事件 */ public void init(Context context, ILogin iLogin) { this.context = context; this.login = iLogin; }public ILogin getLogin() { return login; }public Context getContext() { return context; } }

相关aop lib已经编写完成,接下来就是使用,需要在application中初始化LoginSDK
public class AppContext implements IModuleConfig, IAppLife { private static final String TAG = AppContext.class.getSimpleName(); public AppContext() { }@Override public void attachBaseContext(Context base) { }@Override public void injectAppLifecycle(Context context, List< IAppLife> lifeList) { lifeList.add(this); }@Override public void onCreate(BaseApplication application) { LoginSDK.getInstance().init(application, login); }private ILogin login = new ILogin() { @Override public void login(Context context, int actionDefine) { switch (actionDefine) { case 0: ToastHelper.showMessage(R.string.login_required); IntentUtils.actionWeChatLogin(AppManager.currentActivity(), IReturnType.Mine); break; case 1: ToastHelper.showMessage(R.string.login_required); break; } }@Override public boolean isLogin(Context context) { return component().userManager().hasUser(); } }; }

在具体的业务中使用注解
@LoginIntercept private void toUserPage() { IntentUtils.startActivity(getActivity(), UserActivity.class); }

大功告成,可以优雅的使用登录拦截了,由于时间有限,像权限请求也像登录那样处理即可,可能会接下来的文章继续写权限请求Aop,还有一个需要注意点,在release包混淆中,不要把注解类混淆,不然会报NPE错误
# aop注解 -adaptclassstrings -keepattributes InnerClasses, EnclosingMethod, Signature, *Annotation* -keepnames @org.aspectj.lang.annotation.Aspect class * { ajc* < methods> ; } -keepclassmembers class ** { @com.huaying.aop.login.aspect.LoginFilter < methods> ; }


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