Failed to set registerPlugins on iOS

Hi! I’m having a problem running an app with this plugin installed. I’ve done everything I found on the internet and nothing works… If I comment await FlutterDownloader.initialize(); I can start the application.

Exception:

[   +2 ms] [DEVICE LOG] 2020-01-09 10:10:13.600816+0100  localhost Runner[14546]: methodCallHandler: initialize
[        ] [DEVICE LOG] 2020-01-09 10:10:13.601151+0100  localhost Runner[14546]: startBackgroundIsolate
[        ] [DEVICE LOG] 2020-01-09 10:10:13.639051+0100  localhost Runner[14546]: (Foundation) *** Assertion failure in -[FlutterDownloaderPlugin startBackgroundIsolate:], /Users/breakpoint/Flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.3.4/ios/Classes/FlutterDownloaderPlugin.m:117
[        ] [DEVICE LOG] 2020-01-09 10:10:13.686382+0100  localhost Runner[14546]: (CoreFoundation) *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'failed to set registerPlugins'
[        ] [DEVICE LOG] *** First throw call stack:
[   +4 ms] [DEVICE LOG] (
[        ] [DEVICE LOG]         0   CoreFoundation                      0x000000010a5828db __exceptionPreprocess + 331
[        ] [DEVICE LOG]         1   libobjc.A.dylib                     0x0000000109437ac5 objc_exception_throw + 48
[        ] [DEVICE LOG]         2   CoreFoundation                      0x000000010a582662 +[NSException raise:format:arguments:] + 98
[        ] [DEVICE LOG]         3   Foundation                          0x0000000108b0d76b -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 194
[        ] [DEVICE LOG]         4   Runner                              0x0000000105e50cfe -[FlutterDownloaderPlugin startBackgroundIsolate:] + 782
[        ] [DEVICE LOG]         5   Runner                              0x0000000105e569eb -[FlutterDownloaderPlugin initializeMethodCall:result:] + 187
[        ] [DEVICE LOG]         6   Runner                              0x0000000105e5a7d0 -[FlutterDownloaderPlugin handleMethodCall:result:] + 256
[        ] [DEVICE LOG]         7   Flutter                             0x0000000106a98f95 __45-[FlutterMethodCha<…>
[  +16 ms] methodCallHandler: initialize
[        ] startBackgroundIsolate
[        ] *** First throw call stack:
[        ] (
[        ]      0   CoreFoundation                      0x000000010a5828db __exceptionPreprocess + 331
[        ]      1   libobjc.A.dylib                     0x0000000109437ac5 objc_exception_throw + 48
[        ]      2   CoreFoundation                      0x000000010a582662 +[NSException raise:format:arguments:] + 98
[        ]      3   Foundation                          0x0000000108b0d76b -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 194
[        ]      4   Runner                              0x0000000105e50cfe -[FlutterDownloaderPlugin startBackgroundIsolate:] + 782
[        ]      5   Runner                              0x0000000105e569eb -[FlutterDownloaderPlugin initializeMethodCall:result:] + 187
[        ]      6   Runner                              0x0000000105e5a7d0 -[FlutterDownloaderPlugin handleMethodCall:result:] + 256
[        ]      7   Flutter                             0x0000000106a98f95 __45-[FlutterMethodCha<…>
[   +3 ms] Service protocol connection closed.
[        ] Lost connection to device.

main.dart:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await FlutterDownloader.initialize();

  ...
}

AppDelegate.m:

#include "AppDelegate.h"
#include "GeneratedPluginRegistrant.h"
#include "FlutterDownloaderPlugin.h"

@implementation AppDelegate

void registerPlugins(NSObject<FlutterPluginRegistry>* registry) {
    [FlutterDownloaderPlugin registerWithRegistrar:[registry registrarForPlugin:@"vn.hunghd.flutter_downloader"]];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    if (@available(iOS 10.0, *)) {
        [UNUserNotificationCenter currentNotificationCenter].delegate = (id<UNUserNotificationCenterDelegate>)self;
    }

    [GeneratedPluginRegistrant registerWithRegistry:self];
    [FlutterDownloaderPlugin setPluginRegistrantCallback:registerPlugins];

    return [super application:application didFinishLaunchingWithOptions:launchOptions];
}

@end

flutter doctor:

[✓] Flutter (Channel stable, v1.12.13+hotfix.5, on Mac OS X 10.13.6 17G10021,
    locale en-BA)
 
[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
[✓] Xcode - develop for iOS and macOS (Xcode 10.3)
[✓] Android Studio (version 3.3)
[✓] IntelliJ IDEA Community Edition (version 2019.3.1)
[✓] Connected device (1 available)

• No issues found!

flutter_downloader version:

1.3.4

[y-sihyeon]

@anisalibegic check your “/ios/Runner/AppDelegate.swift” file. I had the same problem. I solved it by adding the code below.

“AppDelegate.swift”

import UIKit
import Flutter
import flutter_downloader

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
    FlutterDownloaderPlugin.setPluginRegistrantCallback(registerPlugins)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

private func registerPlugins(registry: FlutterPluginRegistry) {
    if (!registry.hasPlugin("FlutterDownloaderPlugin")) {
       FlutterDownloaderPlugin.register(with: registry.registrar(forPlugin: "FlutterDownloaderPlugin"))
    }
}

good luck!!

[bhargavsejpalindianic]

@anisalibegic check your “/ios/Runner/AppDelegate.swift” file. I had the same problem. I solved it by adding the code below.

“AppDelegate.swift”

import UIKit
import Flutter
import flutter_downloader

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
    FlutterDownloaderPlugin.setPluginRegistrantCallback(registerPlugins)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

private func registerPlugins(registry: FlutterPluginRegistry) {
    if (!registry.hasPlugin("FlutterDownloaderPlugin")) {
       FlutterDownloaderPlugin.register(with: registry.registrar(forPlugin: "FlutterDownloaderPlugin"))
    }
}

good luck!!

A C function pointer can only be formed from a reference to a ‘func’ or a literal closure