一背景

android 的版本的更替往往需要开发者进行跟进.

Notification 在Android 8.0 上需要做一些兼容的工作.官方指导文档

二适配

适配工作分为两步

1 根据一个channelId 生成NotificationChannel 作为推送通道

public static void init(Context ctx) {
       if (SDK_INT >= 26) {
           String channelId = "dim";
           NotificationManager manager = (NotificationManager) Application.getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);
           if (manager != null) {
               NotificationChannel taco = manager.getNotificationChannel(channelId);
               if (taco == null) {
                   int importance = NotificationManager.IMPORTANCE_HIGH;
                   NotificationChannel channel = new NotificationChannel(channelId, channelId, importance);
                   channel.setDescription(TACO_CHANNEL);
                   manager.createNotificationChannel(channel);
               }
           }
       }
   }

2 所有的通知需要设置 channelId:

设置的方式:

1	new Notification.Builder(ctx).setChannelId(channelId);

到此兼容的工作算是完成了.
但是这里的兼容只是局限在我们自己的业务代码.

三. 业务外的代码怎么办呢?

比如说在个推的GetuiSDK2.10.3.5 并没有对 Notification 做相关的处理.

Q: 怎么办?
A: 使用 AOP 为第三方 SDK 修BUG , 适配新特性 .

AOP 的实现有很多方式,这里我们会讲3种方式来实现这个效果.

一. 使用 lancet ( 饿了么开源的 AOP 框架 )

引入:https://github.com/eleme/lancet

public class NotifactionFix {

     public static final String CHANNEL = "dim";

    @Proxy("notify")
    @TargetClass("android.app.NotificationManager")
    public void notify(int id, Notification notification) {
        if (SDK_INT >= 26) {
            maybeSetChannelId(notification);
        }
        Origin.callVoid();
    }

    @Proxy("notify")
    @TargetClass("android.app.NotificationManager")
    public void notify(String tag, int id, Notification notification) {
        maybeSetChannelId(notification);
        Origin.callVoid();
    }

   public static void maybeSetChannelId(Notification notification) {
        if (SDK_INT >= 26) {
            if (TextUtils.isEmpty(notification.getChannelId())) {
                try {
                    Field mChannelId = Notification.class.getDeclaredField("mChannelId");
                    mChannelId.setAccessible(true);
                    mChannelId.set(notification,CHANNEL);
                } catch (NoSuchFieldException e) {
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

二使用 aspectjX

引入 :https://github.com/HujiangTechnology/gradle_plugin_android_aspectjx

@Aspect
public class NotificationFix {

    public static final String CHANNEL = "dim";

    private static NotificationFix sNotificationFix = new NotificationFix();

    public static NotificationFix aspectOf() {
        return sNotificationFix;
    }

    @Pointcut("call(public void android.app.NotificationManager.notify(..))")
    void notificationManager_notifyMethod() {
    }

    @Before("notificationManager_notifyMethod()")
    public void hookNotificationManager_notifyMethod(JoinPoint joinPoint) {
        Log.e("dim", "hookNotificationManager_notifyMethod: ");
        for (Object arg : joinPoint.getArgs()) {
            if (arg != null && arg instanceof Notification) {
                maybeSetChannelId((Notification) arg);
            }
        }
    }

   public static void maybeSetChannelId(Notification notification) {
        if (SDK_INT >= 26) {
            if (TextUtils.isEmpty(notification.getChannelId())) {
                try {
                    Field mChannelId = Notification.class.getDeclaredField("mChannelId");
                    mChannelId.setAccessible(true);
                    mChannelId.set(notification, CHANNEL);
                } catch (NoSuchFieldException e) {
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

三使用 ASM 框架.

3.1 Android Plugin 处理

在androisjd 打包中加入对 class 的处理
引入’ compile ‘org.ow2.asm:asm:6.0_ALPHA’’

byte[] process(byte[] src) {
       try {
           ClassReader classReader = new ClassReader(src);
           ClassWriter cw = new ClassWriter(classReader, ClassWriter.COMPUTE_MAXS);
           classReader.accept(new AopClassVisitor(cw, sasukeExtension), ClassReader.EXPAND_FRAMES);
           return cw.toByteArray();
       } catch (Exception e) {
           return src;
       }
   }

AopClassVisitor.java

public class AopClassVisitor extends ClassVisitor {
     private String className;

    public AopClassVisitor(ClassWriter cw) {
        super(Opcodes.ASM5, cw);
    }

    @Override
    public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
        className = name;
    }

    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        if (className.equals("red/dim/hook/NotificationFix")) {
            return super.visitMethod(access, name, desc, signature, exceptions);
        }
        return new AopMethodVisitor(super.visitMethod(access, name, desc, signature, exceptions));
    }
}

AopMethodVisitor.java

public class AopMethodVisitor extends MethodVisitor {
    AopMethodVisitor(MethodVisitor methodVisitor) {
        super(Opcodes.ASM5, methodVisitor);
    }

    @Override
    public void visitMethodInsn(int opcode, String owner, String name, String desc, boolean itf) {
        if (opcode == Opcodes.INVOKEINTERFACE
                && "android/app/NotificationManager".equals(owner)
                && "notify".equals(name)
                && "(I;Landroid/app/Notification)V".equals(desc)) {
            visitMethodInsn(Opcodes.INVOKESTATIC, "red/dim/hook/NotificationFix", "notify", "(Landroid/app/NotificationManager;I;Landroid/app/Notification)V", false);
            return;
        }
        if (opcode == Opcodes.INVOKEINTERFACE
                && "android/app/NotificationManager".equals(owner)
                && "notify".equals(name)
                && "(Ljava.lang.String;I;Landroid/app/Notification)V".equals(desc)) {
            visitMethodInsn(Opcodes.INVOKESTATIC, "red/dim/hook/NotificationFix", "notify", "(Landroid/app/NotificationManager;Ljava.lang.String;I;Landroid/app/Notification)V", false);
            return;
        }
        super.visitMethodInsn(opcode, owner, name, desc, itf);
    }

}

总结

上述的代码通过字节码分析将所有的NotificationManager 的 notify 的两个方法的调用都路由到
NotificationFix 的 notify 静态方法上.

3.2 SDK 处理

在 SDK 加入处理类
red.dim.hook.NotificationFix.java

public class NotificationFix {

    public static final String CHANNEL = "dim";

    public static void notify(NotificationManager notificationManager, int id, Notification notification) {
        maybeSetChannelId(notification);
        notificationManager.notify(id, notification);
    }

    public static void notify(NotificationManager notificationManager, String tag, int id, Notification notification) {
        maybeSetChannelId(notification);
        notificationManager.notify(tag, id, notification);
    }

    private static void maybeSetChannelId(Notification notification) {
        if (SDK_INT >= 26) {
            if (TextUtils.isEmpty(notification.getChannelId())) {
                try {
                    Field mChannelId = Notification.class.getDeclaredField("mChannelId");
                    mChannelId.setAccessible(true);
                    mChannelId.set(notification, CHANNEL);
                } catch (NoSuchFieldException e) {
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

四总结

三种 AOP 方式各有优势

使用 AOP 来为第三方 SDK 打 CALL

一 背景

二 适配