[BUG] requestPermissionExtend results in null value first time

[Sahkay]

Describe the bug
When using PhotoManager.requestPermissionExtend() (I am testing on Android API 31), it results in a null value when run for the first time for that app even if permissions are granted. Repeating the future after permissions are applied works fine, just the first time has the issue. There are no observable errors.

To Reproduce
Steps to reproduce the behavior:

1. Wait for PhotoManager.requestPermissionExtend()
2. The future completes as null

Expected behavior
The future should wait until the user selects the permission option and then complete with the permission value.

Screenshots
If applicable, add screenshots to help explain your problem.

Flutter version
[✓] Flutter (Channel stable, 3.7.1, on macOS 12.4 21F79 darwin-x64, locale en-AU)
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[!] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
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• Platform android-33, build-tools 33.0.0
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[!] Android Studio (version 2022.1)
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🔨 https://plugins.jetbrains.com/plugin/9212-flutter
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• Try updating or re-installing Android Studio.

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Scanning for devices is taking a long time...[✓] Connected device (3 available)
• sdk gphone64 x86 64 (mobile) • emulator-5554 • android-x64 • Android 12 (API 31) (emulator)
• macOS (desktop) • macos • darwin-x64 • macOS 12.4 21F79 darwin-x64
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Smartphone (please complete the following information):

• Device: Pixel 5 Emulator
• OS: Android
• Version Api 31

[AlexV525]

There are no observable errors.

If the permission request returns null, there must be a NPE exception. Please re-identify which method is wrong and provide usage code, logs and screen recordings.

[Sahkay]

logcat via android studio shows no messages at level error or higher.
Screen recording will provide no extra information for this issue.
Here is some example code

import 'package:flutter/material.dart';
import 'package:photo_manager/photo_manager.dart';

class MediaLibraryScreen extends StatefulWidget {
  final String? mediaType;
  final AssetPathEntity? folder;
  final bool multiple;

  const MediaLibraryScreen({this.mediaType, this.folder, this.multiple = false, Key? key}) : super(key: key);

  @override
  State<MediaLibraryScreen> createState() => _MediaLibraryScreenState();
}

class _MediaLibraryScreenState extends State<MediaLibraryScreen> {
  Future<dynamic>? mediaLibraryRequest;

  @override
  Widget build(BuildContext context) {
    mediaLibraryRequest ??= Future.wait([
      PhotoManager.requestPermissionExtend(),
      widget.folder == null ? PhotoManager.getAssetPathList() : widget.folder!.getAssetListPaged(page: 0, size: 50),
    ]);
    return Scaffold(
      body: SafeArea(
        child: FutureBuilder(
          future: mediaLibraryRequest,
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              PermissionState mediaPerms = snapshot.data[0] as PermissionState;
              List<dynamic> assetList = snapshot.data[1];
              if (mediaPerms.hasAccess) {
                return GridView.count(
                  primary: true,
                  crossAxisCount: 3,
                  children: [
                    ...assetList
                        .map((item) =>
                        Container(
                          child: Text(item.name),
                        ))
                        .toList(),
                  ],
                );
              } else if (snapshot.data[0] != null) {
                return Center(child: Text("Test"));
              } else {
                return Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Text("Media Permissions were denied"),
                    OutlinedButton(
                      child: Text("Open Settings"),
                      onPressed: () => PhotoManager.openSetting(),
                    ),
                  ],
                );
              }
            } else if (snapshot.connectionState == ConnectionState.done) {
              return Center(child: Text(snapshot.data?[0] ?? "null"));
            } else {
              return const Center(
                child: CircularProgressIndicator(),
              );
            }
          },
        ),
      ),
    );
  }
}

In the example code, if the page is opened for the first time, after the prompt is accepted for file access, the text "null" is shown on screen due to the else if.

[Sahkay]

Sorry clicked close with comment by accident.

[Sahkay]

I found the cause of the issue, when running the double future in the example it causes the error but running the requestPermissionExtend on its own, the issue does not occur. So the issue either lies with the future waiting or with the PhotoManager.getAssetPathList() running with requestPermissionExtend. There is also the fact that getAssetPathList is returning an empty list even when there is a photo in the downloads folder.

[AlexV525]

mediaLibraryRequest ??= Future.wait([
PhotoManager.requestPermissionExtend(),
widget.folder == null ? PhotoManager.getAssetPathList() : widget.folder!.getAssetListPaged(page: 0, size: 50),
]);

This is an invalid usage. Please follow the simple example which already described how to integrate with the plugin.

Regarding the empty list, see #852.