AOP-AspectJ实践

0 引入包

根目录下的build.gradle中，dependencies添加以下两个依赖，很多网上文章说只需依赖第一个，运行时候会报错：

  classpath 'com.hujiang.aspectjx:gradle-android-plugin-aspectjx:1.1.0'
  classpath 'org.aspectj:aspectjtools:1.8.14'

然后再主项目或者库的build.gradle中增加AspectJ的依赖：

compile 'org.aspectj:aspectjrt:1.8.14'

同时在build.gradle中加入AspectJX模块：

apply plugin: 'android-aspectjx'

1 定义切面类

TestAnnoAspect

@Aspect
public class TestAnnoAspect {
    private static final String TAG = "jack";

    @Before("execution(* com.jack.aop.MainActivity.onCreate(..))")
    public void onActivityMethodBefore(JoinPoint joinPoint) throws Throwable {
        String key = joinPoint.getSignature().toString();
        Log.d(TAG, "onActivityMethodBefore: " + key);
    }

    @After("execution(* android.app.Activity.onResume(..))")
    public void onActivityMethodafter(JoinPoint joinPoint) throws Throwable {
        String key = joinPoint.getSignature().toString();
        Log.d(TAG, "onActivityMethodafter: " + key);
    }
}

在类的最开始，我们使用@Aspect注解来定义这样一个AspectJ文件，编译器在编译的时候，就会自动去解析，并不需要主动去调用AspectJ类里面的代码。

MainActivity

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

经过编译后：MainActivity.class

public class MainActivity
  extends AppCompatActivity
{
  private static final JoinPoint.StaticPart ajc$tjp_0;
    private static final JoinPoint.StaticPart ajc$tjp_1;

    private static void ajc$preClinit()
    {
        Factory localFactory = new Factory("MainActivity.java", MainActivity.class);
        ajc$tjp_0 = localFactory.makeSJP("method-execution",
                localFactory.makeMethodSig("4", "onCreate", "com.jack.aop.MainActivity",
                        "android.os.Bundle", "savedInstanceState", "", "void"), 11);
        ajc$tjp_1 = localFactory.makeSJP("method-execution", 
                localFactory.makeMethodSig("4", "onResume", "com.jack.aop.MainActivity", 
                        "", "", "", "void"), 18);
    }

    protected void onCreate(Bundle savedInstanceState)
    {
        Bundle localBundle = savedInstanceState;
        JoinPoint localJoinPoint = Factory.makeJP(ajc$tjp_0, this, this, localBundle);
        TestAnnoAspect.aspectOf().onActivityMethodBefore(localJoinPoint);
        super.onCreate(savedInstanceState);
        setContentView(2131296283);
    }

    protected void onResume()
    {
        JoinPoint localJoinPoint = Factory.makeJP(ajc$tjp_1, this, this);
        try
        {
            super.onResume();
        }
        catch (Throwable localThrowable)
        {
            TestAnnoAspect.aspectOf().onActivityMethodafter(localJoinPoint);throw localThrowable;
        }
        TestAnnoAspect.aspectOf().onActivityMethodafter(localJoinPoint);
    }

    static {}
}

可以看到在onCreate和onResume中插入了代码。

完毕