判断是否开启推送

/**
 *  check if user allow local notification of system setting
 *
 *  @return YES-allowed,otherwise,NO.
 */
+ (BOOL)isAllowedNotification {
    //iOS8 check if user allow notification
    if ([UIDevice isSystemVersioniOS8]) {// system is iOS8
        UIUserNotificationSettings *setting = [[UIApplication sharedApplication] currentUserNotificationSettings];
        if (UIUserNotificationTypeNone != setting.types) {
            return YES;
        }
    } else {//iOS7
        UIRemoteNotificationType type = [[UIApplication sharedApplication] enabledRemoteNotificationTypes];
        if(UIRemoteNotificationTypeNone != type)
            return YES;
    }
    
    return NO;
}

以上为判断是不是开启了推送

/**
 *  check if the system version is iOS8
 *
 *  @return YES-is iOS8,otherwise,below iOS8
 */
+ (BOOL)isSystemVersioniOS8 {
    //check systemVerson of device
    UIDevice *device = [UIDevice currentDevice];
    float sysVersion = [device.systemVersion floatValue];
    
    if (sysVersion >= 8.0f) {
        return YES;
    }
    return NO;
}

以上判断是不是iOS8