[ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: NoSuchMethodError: The method 'matchAsPrefix' was called on null.

[shreyash333]

Hover doctor

[√] Flutter (Channel beta, 1.26.0-17.6.pre, on Microsoft Windows [Version 10.0.19041.867], locale en-US)
• Flutter version 1.26.0-17.6.pre at C:\flutter
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[!] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
• Android SDK at C:\Users\Asus\AppData\Local\Android\sdk
• Platform android-30, build-tools 30.0.3
• Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
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Run flutter doctor --android-licenses to accept the SDK licenses.
See https://flutter.dev/docs/get-started/install/windows#android-setup for more details.

[√] Chrome - develop for the web
• Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[√] Android Studio (version 4.1.0)
• Android Studio at C:\Program Files\Android\Android Studio
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• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)

[√] VS Code (version 1.54.3)
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[√] Connected device (3 available)
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$ hover doctor
hover: Running on linux
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hover: Sharing flutter version
[...]

Error output

[ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: NoSuchMethodError: The method 'matchAsPrefix' was called on null.
E/flutter (14919): Receiver: null
Tried calling: matchAsPrefix("application/x-www-form-urlencoded", 0)
E/flutter (14919): #0 StringScanner.matches (package:string_scanner/src/string_scanner.dart:171:26)
E/flutter (14919): #1 StringScanner.scan (package:string_scanner/src/string_scanner.dart:128:21)
E/flutter (14919): #2 new MediaType.parse. (package:http_parser/src/media_type.dart:48:17)
E/flutter (14919): #3 wrapFormatException (package:http_parser/src/utils.dart:13:16)
E/flutter (14919): #4 new MediaType.parse (package:http_parser/src/media_type.dart:46:7)
E/flutter (14919): #5 Request._contentType (package:http/src/request.dart:157:22)
E/flutter (14919): #6 Request.encoding= (package:http/src/request.dart:62:23)
E/flutter (14919): #7 BaseClient._sendUnstreamed (package:http/src/base_client.dart:78:35)
E/flutter (14919): #8 BaseClient.post (package:http/src/base_client.dart:32:7)
E/flutter (14919): #9 post. (package:http/http.dart:70:16)
E/flutter (14919): #10 _withClient (package:http/http.dart:166:20)
E/flutter (14919): #11 post (package:http/http.dart:69:5)

[shreyash333]

Map<String, dynamic> jsonMap = {
"token": jwttoken,
"student_id": user.student_id.toString()
};

var res = await http.post('http://10.0.2.2:12345/getCurrentDB',
    body: jsonMap,
    headers: {
      "Accept": "application/json",
      "Content-Type": "application/x-www-form-urlencoded"
    },
    encoding: Encoding.getByName("utf-8"));