Flutter flutter_webview_plugin error [NSNull length]: unrecognized selector sent to instance on ios-CodePudding

I am using flutter_webview_plugin: ^0.4.0 to load a website. The app works fine on Android. On IOs I am getting the error

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSNull length]: unrecognized selector sent to instance 0x1fb513aa0'

for the line NSURL *scopeUrl = [NSURL fileURLWithPath:localUrlScope]; in file FlutterWebviewPlugin in Xcode.

I've added

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
    <key>NSAllowsArbitraryLoadsInWebContent</key>
    <true/>
</dict>

from the docs in my Info.plist.

I tried adding

<key>io.flutter.embedded_views_preview</key>
<string>YES</string>

in my Info.plist but it didn't work. I also tried replacing <string>YES</string> with <true/> which didn't work too.

I've tried setting the target IOs versions from 9.0 to 13.0 and the issue still exists.

I am using the file picker and alert dialog features provided by this package so I cannot use any another.

I've wrapped the URL with Uri.encodeFull().

The block of code where the error occurs is as follows:

if (@available(iOS 9.0, *)) {
                    if(localUrlScope == nil) {
                        [self.webview loadFileURL:htmlUrl allowingReadAccessToURL:htmlUrl];
                    }
                    else {
                        NSURL *scopeUrl = [NSURL fileURLWithPath:localUrlScope]; //ERROR OCCURING HERE
                        [self.webview loadFileURL:htmlUrl allowingReadAccessToURL:scopeUrl];
                    }
                } else {
                    @throw @"not available on version earlier than ios 9.0";
                }

I ran flutter doctor and it didn't show any issues.

Everytime I change something in the code, I delete Podfile.lock, build folder, run flutter clean so the changes made in some previous attempts aren't messing anything.

I am using an M1 Mac with Dart 2.13.4, Flutter 2.5.0, XCode 13.0 (13A233)

CodePudding user response：

I have had this issue earlier when I was working on a similar thing with this package, After long hours of bashing head around, I found this from

Thing is when you set withLocalUrl to true, you have to Add localUrlScope option to be set to a path to a directory in your flutter code or you just remove withLocalUrl:true from it.

As this option is ignored in Android so it works with no issues in it but for iOS we need to be specific with this