反射获取当前可见activityName

public static String getTopActivityName() {

        long start = System.currentTimeMillis();

        try {

            Class activityThreadClass = Class.forName("android.app.ActivityThread");

            Object activityThread = activityThreadClass.getMethod("currentActivityThread").invoke(null);

            Field activitiesField = activityThreadClass.getDeclaredField("mActivities");

            activitiesField.setAccessible(true);

            Map<Object, Object> activities;

            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {

                activities = (HashMap<Object, Object>) activitiesField.get(activityThread);

            } else {

                activities = (ArrayMap<Object, Object>) activitiesField.get(activityThread);

            }

            if (activities.size() < 1) {

                return null;

            }

            for (Object activityRecord : activities.values()) {

                Class activityRecordClass = activityRecord.getClass();

                Field pausedField = activityRecordClass.getDeclaredField("paused");

                pausedField.setAccessible(true);

                if (!pausedField.getBoolean(activityRecord)) {

                    Field activityField = activityRecordClass.getDeclaredField("activity");

                    activityField.setAccessible(true);

                    Activity activity = (Activity) activityField.get(activityRecord);

                    return activity.getClass().getName();

                }

            }

        } catch (Exception e) {

            e.printStackTrace();

        } finally {

            long cost = System.currentTimeMillis() - start;

            MatrixLog.d(TAG, "[getTopActivityName] Cost:%s", cost);

        }

        return null;

    }