iOS开发之打开系统设置通知权限页面

- (void)viewDidAppear:(BOOL)animated 
{
　　//首先判断应用通知是否授权，注意iOS10.0之后方法不一样
    if (@available(iOS 10.0, *)) {
        [[UNUserNotificationCenter currentNotificationCenter] getNotificationSettingsWithCompletionHandler:^(UNNotificationSettings * _Nonnull settings) {
            if (settings.authorizationStatus == UNAuthorizationStatusNotDetermined)
            {
                NSLog(@"未选择");
                [self opentNotificationAlert];
            }else if (settings.authorizationStatus == UNAuthorizationStatusDenied){
                NSLog(@"未授权");
                [self opentNotificationAlert];
            }else if (settings.authorizationStatus == UNAuthorizationStatusAuthorized){
                NSLog(@"已授权");
            }
        }];
    } else {
        if ([[UIApplication sharedApplication] currentUserNotificationSettings].types == 0) {
            [self opentNotificationAlert];
        }
    }
}

/** 跳转系统设置方法*/
- (void)opentNotificationAlert 
{
    /**< 弹出框 */
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"推送通知关闭"
                                                                             message:@"请前往打开通知，获取更多精彩瞬间！"
                                                                      preferredStyle:UIAlertControllerStyleAlert];
    [alertController addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {

    }]];
    [alertController addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        [self.presentedViewController dismissViewControllerAnimated:YES completion:nil];
        if (@available(iOS 10.0, *)) {
            [[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString] options:@{} completionHandler:nil];
        } else {
            [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs:root=NOTIFICATIONS_ID&path=com.xxx.xxx"]];//prefs:root=服务&path=项目bundleID
　　　　　} 

　　}]; 
　　[self presentViewController:alertController animated:YES completion:nil]; 
}