Android之AOP架构<第三篇>：网络判断

直接贴代码

[第一步] 网络判断切面

/**
 * 网络判断切面
 */
@Aspect
public class CheckNetAspect {


    @Pointcut("execution(* com.example.aopdemo.MainActivity.test(..))")
    public void checkNetBehavior() {

    }

    @Around("checkNetBehavior()")
    public Object checkNet(ProceedingJoinPoint joinPoint) throws Throwable {
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        CheckNet annotation = signature.getMethod().getAnnotation(CheckNet.class);
        if (annotation != null) {
            Object object = joinPoint.getThis();
            Context context = getContext(object);
            if (context != null) {
                if (!isNetworkAvailable(context)) {
                    Toast.makeText(context,"请检查您的网络",Toast.LENGTH_LONG).show();
                    return null;
                }
            }
        }
        return joinPoint.proceed();
    }

    /**
     * 通过对象获取上下文
     *
     * @param object
     * @return
     */
    private Context getContext(Object object) {
        if (object instanceof Activity) {
            return (Activity) object;
        } else if (object instanceof Fragment) {
            Fragment fragment = (Fragment) object;
            return fragment.getActivity();
        } else if (object instanceof View) {
            View view = (View) object;
            return view.getContext();
        }
        return null;
    }

    /**
     * 检查当前网络是否可用
     *
     * @return
     */
    private static boolean isNetworkAvailable(Context context) {
        ConnectivityManager connectivityManager = (ConnectivityManager)
                context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (connectivityManager != null) {
            NetworkInfo[] networkInfo = connectivityManager.getAllNetworkInfo();

            if (networkInfo != null && networkInfo.length > 0) {
                for (int i = 0; i < networkInfo.length; i++) {
                    if (networkInfo[i].getState() == NetworkInfo.State.CONNECTED) {
                        return true;
                    }
                }
            }
        }
        return false;
    }

}

在名字叫CheckNet的注解上埋下切点。

[自定义注解]

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface CheckNet {
}

[注解的使用]

@CheckNet
private void test(){
    Log.i("yunchong", "开始进行网络判断！");
}

[本章完...]