Flutter Bad State: no element - list of objects from map not working

Question

My screen is shown within a FutureBuilder and takes in a usersMap and a postsMapsList. I have a function that's called in initState which takes all the users and post out of those maps and turns them into lists of custom objects. In a widget I have I use UserSearchResult user = usersList.where((u) => u.uid == postsList[index].uid).single; to get the user object for a post but it prints State: no element. After some debugging, I realized that no posts are being added to the postsList which makes no sense because a different screen uses the same function to add posts and it works. I appreciate any ideas on how to fix this.

The postsMaps list consists of multiple maps containing posts (each user has a map of posts). So in this function, I take each map then each post in it, and create a Post object with it. I tried using forEach and for in for the list but both ways don't work.

Here's the relevent snippet of the function:

postsMaps.forEach((postsMap) {
      postsMap.forEach((index, value) {
        setState(() {
          postsLoading = true;
        });

        final post = Post.fromJson(value.data() as Map<String, dynamic>);

        print('Post: ${value.data()}');

        if (postsList
            .where((e) => e.postId == post.postId)
            .toList()
            .isEmpty) {
          setState(() {
            postsList.add(post);
          });
        }
      });
    });

Error:

The following StateError was thrown building HomeScreen(dirty, state: _HomeScreenState#9ef08):
Bad state: No element

The relevant error-causing widget was: 
  HomeScreen HomeScreen:file:///Users/cjm/AndroidStudioProjects/globe_rebrand/lib/screens/main/tab_bar_view.dart:126:24
When the exception was thrown, this was the stack: 
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 266:49      throw_
dart-sdk/lib/core/iterable.dart 654:63                                            get single
packages/globe_rebrand/screens/main/home_screen.dart 123:71                       build

Line where the error is:

UserSearchResult user = usersList.where((u) => u.uid == postsList[index].uid).single;

Printed postList:

postsList: [Post: {postId: 1663650914746, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663650914746%2F%5B%238be79%5D_post.png?alt=media&token=ae1f1423-2de5-444d-baa7-6c59f85f7067], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663804907974, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663804907974%2F%5B%23c0252%5D_post.png?alt=media&token=d17bfbb6-be14-4536-b203-4ed83a76b5cb], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663650914746, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663650914746%2F%5B%238be79%5D_post.png?alt=media&token=ae1f1423-2de5-444d-baa7-6c59f85f7067], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663804907974, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663804907974%2F%5B%23c0252%5D_post.png?alt=media&token=d17bfbb6-be14-4536-b203-4ed83a76b5cb], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663650914746, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663650914746%2F%5B%238be79%5D_post.png?alt=media&token=ae1f1423-2de5-444d-baa7-6c59f85f7067], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663804907974, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663804907974%2F%5B%23c0252%5D_post.png?alt=media&token=d17bfbb6-be14-4536-b203-4ed83a76b5cb], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663650914746, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663650914746%2F%5B%238be79%5D_post.png?alt=media&token=ae1f1423-2de5-444d-baa7-6c59f85f7067], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663804907974, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663804907974%2F%5B%23c0252%5D_post.png?alt=media&token=d17bfbb6-be14-4536-b203-4ed83a76b5cb], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1662259492485, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%234f06c%5D_post.png?alt=media&token=c3daa4b9-b1b7-4ac7-99ba-1c9f0872e77a, https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%23dc27b%5D_post.png?alt=media&token=c21a4a15-c729-4c94-a9a6-f0ed88e4d57e], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663378122899, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663378122899%2F%5B%2392b8b%5D_post.png?alt=media&token=6bdc32a9-76c8-4f42-85ed-7659fe63b652], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663484428194, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663484428194%2F%5B%2319e71%5D_post.png?alt=media&token=5ef84c5c-00f8-4996-9134-71b368247ba6], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663548532558, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663548532558%2F%5B%2303070%5D_post.png?alt=media&token=320805f6-eb2a-4518-af4c-ea5b9e9217dd], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663644750049, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663644750049%2F%5B%23653c1%5D_post.png?alt=media&token=3ebfb68e-214e-4e04-a77e-fc4ec7333123], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1662259492485, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%234f06c%5D_post.png?alt=media&token=c3daa4b9-b1b7-4ac7-99ba-1c9f0872e77a, https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%23dc27b%5D_post.png?alt=media&token=c21a4a15-c729-4c94-a9a6-f0ed88e4d57e], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663378122899, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663378122899%2F%5B%2392b8b%5D_post.png?alt=media&token=6bdc32a9-76c8-4f42-85ed-7659fe63b652], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663484428194, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663484428194%2F%5B%2319e71%5D_post.png?alt=media&token=5ef84c5c-00f8-4996-9134-71b368247ba6], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663548532558, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663548532558%2F%5B%2303070%5D_post.png?alt=media&token=320805f6-eb2a-4518-af4c-ea5b9e9217dd], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663644750049, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663644750049%2F%5B%23653c1%5D_post.png?alt=media&token=3ebfb68e-214e-4e04-a77e-fc4ec7333123], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1662259492485, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%234f06c%5D_post.png?alt=media&token=c3daa4b9-b1b7-4ac7-99ba-1c9f0872e77a, https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%23dc27b%5D_post.png?alt=media&token=c21a4a15-c729-4c94-a9a6-f0ed88e4d57e], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663378122899, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663378122899%2F%5B%2392b8b%5D_post.png?alt=media&token=6bdc32a9-76c8-4f42-85ed-7659fe63b652], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663484428194, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663484428194%2F%5B%2319e71%5D_post.png?alt=media&token=5ef84c5c-00f8-4996-9134-71b368247ba6], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663548532558, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663548532558%2F%5B%2303070%5D_post.png?alt=media&token=320805f6-eb2a-4518-af4c-ea5b9e9217dd], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663644750049, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663644750049%2F%5B%23653c1%5D_post.png?alt=media&token=3ebfb68e-214e-4e04-a77e-fc4ec7333123], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1662259492485, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%234f06c%5D_post.png?alt=media&token=c3daa4b9-b1b7-4ac7-99ba-1c9f0872e77a, https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%23dc27b%5D_post.png?alt=media&token=c21a4a15-c729-4c94-a9a6-f0ed88e4d57e], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663378122899, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663378122899%2F%5B%2392b8b%5D_post.png?alt=media&token=6bdc32a9-76c8-4f42-85ed-7659fe63b652], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663484428194, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663484428194%2F%5B%2319e71%5D_post.png?alt=media&token=5ef84c5c-00f8-4996-9134-71b368247ba6], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663548532558, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663548532558%2F%5B%2303070%5D_post.png?alt=media&token=320805f6-eb2a-4518-af4c-ea5b9e9217dd], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663644750049, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663644750049%2F%5B%23653c1%5D_post.png?alt=media&token=3ebfb68e-214e-4e04-a77e-fc4ec7333123], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}]

Printed usersList:

usersList: [Result: {profile: Profile: {profileInfo: Profile: {pfpUrl: https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2F1662335024351_pfp.png?alt=media&token=90dda6d3-5875-45f6-bce8-d5c2f2a2dca2, displayName: name}, posts: [Post: {postId: 1662259492485, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%234f06c%5D_post.png?alt=media&token=c3daa4b9-b1b7-4ac7-99ba-1c9f0872e77a, https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%23dc27b%5D_post.png?alt=media&token=c21a4a15-c729-4c94-a9a6-f0ed88e4d57e], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663378122899, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663378122899%2F%5B%2392b8b%5D_post.png?alt=media&token=6bdc32a9-76c8-4f42-85ed-7659fe63b652], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663484428194, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663484428194%2F%5B%2319e71%5D_post.png?alt=media&token=5ef84c5c-00f8-4996-9134-71b368247ba6], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663548532558, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663548532558%2F%5B%2303070%5D_post.png?alt=media&token=320805f6-eb2a-4518-af4c-ea5b9e9217dd], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663644750049, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663644750049%2F%5B%23653c1%5D_post.png?alt=media&token=3ebfb68e-214e-4e04-a77e-fc4ec7333123], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1662259492485, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%234f06c%5D_post.png?alt=media&token=c3daa4b9-b1b7-4ac7-99ba-1c9f0872e77a, https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%23dc27b%5D_post.png?alt=media&token=c21a4a15-c729-4c94-a9a6-f0ed88e4d57e], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663378122899, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663378122899%2F%5B%2392b8b%5D_post.png?alt=media&token=6bdc32a9-76c8-4f42-85ed-7659fe63b652], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663484428194, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663484428194%2F%5B%2319e71%5D_post.png?alt=media&token=5ef84c5c-00f8-4996-9134-71b368247ba6], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663548532558, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663548532558%2F%5B%2303070%5D_post.png?alt=media&token=320805f6-eb2a-4518-af4c-ea5b9e9217dd], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663644750049, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663644750049%2F%5B%23653c1%5D_post.png?alt=media&token=3ebfb68e-214e-4e04-a77e-fc4ec7333123], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1662259492485, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%234f06c%5D_post.png?alt=media&token=c3daa4b9-b1b7-4ac7-99ba-1c9f0872e77a, https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%23dc27b%5D_post.png?alt=media&token=c21a4a15-c729-4c94-a9a6-f0ed88e4d57e], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663378122899, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663378122899%2F%5B%2392b8b%5D_post.png?alt=media&token=6bdc32a9-76c8-4f42-85ed-7659fe63b652], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663484428194, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663484428194%2F%5B%2319e71%5D_post.png?alt=media&token=5ef84c5c-00f8-4996-9134-71b368247ba6], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663548532558, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663548532558%2F%5B%2303070%5D_post.png?alt=media&token=320805f6-eb2a-4518-af4c-ea5b9e9217dd], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663644750049, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663644750049%2F%5B%23653c1%5D_post.png?alt=media&token=3ebfb68e-214e-4e04-a77e-fc4ec7333123], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1662259492485, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%234f06c%5D_post.png?alt=media&token=c3daa4b9-b1b7-4ac7-99ba-1c9f0872e77a, https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1662259492485%2F%5B%23dc27b%5D_post.png?alt=media&token=c21a4a15-c729-4c94-a9a6-f0ed88e4d57e], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663378122899, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663378122899%2F%5B%2392b8b%5D_post.png?alt=media&token=6bdc32a9-76c8-4f42-85ed-7659fe63b652], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663484428194, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663484428194%2F%5B%2319e71%5D_post.png?alt=media&token=5ef84c5c-00f8-4996-9134-71b368247ba6], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663548532558, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663548532558%2F%5B%2303070%5D_post.png?alt=media&token=320805f6-eb2a-4518-af4c-ea5b9e9217dd], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Post: {postId: 1663644750049, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/HqtGLN1c32VHhCn2n2To6gC2qbA2%2Fposts%2F1663644750049%2F%5B%23653c1%5D_post.png?alt=media&token=3ebfb68e-214e-4e04-a77e-fc4ec7333123], uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}]}, uid: HqtGLN1c32VHhCn2n2To6gC2qbA2}, Result: {profile: Profile: {profileInfo: Profile: {pfpUrl: https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2F%5B%2390398%5D_pfp.png?alt=media&token=681b3bf4-3dc4-4062-a1b0-875d0425c90b, displayName: username}, posts: [Post: {postId: 1663650914746, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663650914746%2F%5B%238be79%5D_post.png?alt=media&token=ae1f1423-2de5-444d-baa7-6c59f85f7067], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663804907974, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663804907974%2F%5B%23c0252%5D_post.png?alt=media&token=d17bfbb6-be14-4536-b203-4ed83a76b5cb], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663650914746, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663650914746%2F%5B%238be79%5D_post.png?alt=media&token=ae1f1423-2de5-444d-baa7-6c59f85f7067], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663804907974, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663804907974%2F%5B%23c0252%5D_post.png?alt=media&token=d17bfbb6-be14-4536-b203-4ed83a76b5cb], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663650914746, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663650914746%2F%5B%238be79%5D_post.png?alt=media&token=ae1f1423-2de5-444d-baa7-6c59f85f7067], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663804907974, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663804907974%2F%5B%23c0252%5D_post.png?alt=media&token=d17bfbb6-be14-4536-b203-4ed83a76b5cb], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663650914746, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663650914746%2F%5B%238be79%5D_post.png?alt=media&token=ae1f1423-2de5-444d-baa7-6c59f85f7067], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}, Post: {postId: 1663804907974, imageUrls: [https://firebasestorage.googleapis.com/v0/b/globe-rebrand.appspot.com/o/PeDVktc9O1bbhMbewRrie8taQ4E3%2Fposts%2F1663804907974%2F%5B%23c0252%5D_post.png?alt=media&token=d17bfbb6-be14-4536-b203-4ed83a76b5cb], uid: PeDVktc9O1bbhMbewRrie8taQ4E3}]}, uid: PeDVktc9O1bbhMbewRrie8taQ4E3}]

Answer 1

if (postsList.where((e) => e.postId == post.postId).toList().isEmpty)

for this code, you are trying to check if the postList is contains post or not. if not, then add the post to the postList, is it right?

here another elegant workaround:

// in your Post model, add this code.
// this code added , so we can able to compare 2 object of Post
class Post {
.....
 @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is Post &&
          runtimeType == other.runtimeType &&
          productId == other.id;

  @override
  int get hashCode => id.hashCode;
}

then now we can compare 2 object Post,

.....
 if (postsList.contains(post)){
    setState(() {
      postsList.add(post);
    });
}
print(postList); // you must see the post just added to postList

---

update

• What caused error: the single

usersList.where((u) => u.uid == postsList[index].uid).single;

• why? because you use the single for your search user. There's a condition when result is null (not match any user) or maybe more than 1.

E get single {
  Iterator<E> it = iterator;
  if (!it.moveNext()) throw IterableElementError.noElement();

• workaroud: opsi 1: use firstWhere

UserSearchResult? user = usersList.firstWhere((u) => u.uid == postsList[index].uid , orElse: () => 'No matching User found');

• opsi 2 : use package:collection

import 'package:collection';
...

UserSearchResult? user = usersList.firstWhereOrNull((u) => u.uid == postsList[index].uid );

if no match user , then it will return null;

hope its solve your issue.