flutter_line_sdk

flutter_line_sdk

A Flutter plugin that lets developers access LINE's native SDKs in Flutter apps with Dart.

The plugin helps you integrate LINE Login features in your app. You can redirect users to LINE or a web page where they log in with their LINE credentials. Example:

import 'package:flutter_line_sdk/flutter_line_sdk.dart';

void login() async {
    try {
        final result = await LineSDK.instance.login();
        setState(() {
            _userProfile = result.userProfile;
            // user id -> result.userProfile?.userId
            // user name -> result.userProfile?.displayName
            // user avatar -> result.userProfile?.pictureUrl
            // etc...
        });
    } on PlatformException catch (e) {
        // Error handling.
        print(e);
    }
}

For more examples, see the example app and API definitions.

Prerequisites

From version 2.0, flutter_line_sdk supports null safety. If you are still seeking a legacy version without null safety, check version 1.3.0.

• Flutter 3.44.0 or later. Version 3.0 relies on Flutter's built-in Kotlin support for Android builds; if your project is still on an older Flutter version, use flutter_line_sdk 2.x instead.
• iOS 15.0 or later as the deployment target
• Android minSdkVersion set to 24 or higher (Android 7.0 or later)
• LINE Login channel linked to your app

To access your LINE Login channel from a mobile platform, you need some extra configuration. In the LINE Developers console, go to your LINE Login channel settings, and enter the below information on the App settings tab.

iOS app settings

Setting	Description
iOS bundle ID	Required. Bundle identifier of your app. In Xcode, find it in your Runner project settings, on the General tab. Must be lowercase, like com.example.app. You can specify multiple bundle identifiers by typing each one on a new line.
iOS universal link	Optional. Set to the universal link configured for your app. For more information on how to handle the login process using a universal link, see Universal Links support.

Android app settings

Setting	Description
Android package name	Required. Application's package name used to launch the Google Play store.
Android package signature	Optional. You can set multiple signatures by typing each one on a new line.
Android scheme	Optional. Custom URL scheme used to launch your app.

Installation

Adding flutter_line_sdk package

Use the standard way of adding this package to your Flutter app, as described in the Flutter documentation:

flutter pub add flutter_line_sdk

Now, the Dart part of flutter_line_sdk should be installed. Next, you need to set up LINE SDK for iOS and Android projects, respectively.

Set up LINE SDK

iOS

Open the file ios/Runner/Info.plist in a text editor and insert this snippet just before the last </dict> tag:

<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleTypeRole</key>
    <string>Editor</string>
    <key>CFBundleURLSchemes</key>
    <array>
      <!-- Specify URL scheme to use when returning from LINE to your app. -->
      <string>line3rdp.$(PRODUCT_BUNDLE_IDENTIFIER)</string>
    </array>
  </dict>
</array>
<key>LSApplicationQueriesSchemes</key>
<array>
  <!-- Specify URL scheme to use when launching LINE from your app. -->
  <string>lineauth2</string>
</array>

Because LINE SDK now requires iOS 15.0 or above to provide underlying native features, while the default deployment target of Flutter is 13.0, you must set the deployment target to 15.0 or higher.

Swift Package Manager integration (default)

Following Flutter's official direction, Swift Package Manager is the default way of managing iOS native dependencies since Flutter 3.44, and it is the integration path this plugin primarily targets. The bundled example app uses Swift Package Manager exclusively and cannot be built with Swift Package Manager opted out.

Open the project and increase the Minimum Deployments of your app's target to 15.0.

CocoaPods integration (maintenance mode)

CocoaPods integration keeps working and remains supported, but it is in maintenance mode, in line with Flutter's own plan for CocoaPods. If your project has opted out of Swift Package Manager, add this line in the Runner target in ios/Podfile:

target 'Runner' do
+ platform :ios, '15.0'

  use_frameworks!
  use_modular_headers!
  ...

Android

To ensure compatibility with the latest features, you need to update the minSdk version in your app's build.gradle file to 24 or higher.

Here's how you can do it:

1. Open your app's build.gradle file.
2. Locate the android block, and within it, find the defaultConfig block.
3. In the defaultConfig block, replace the current minSdk value with 24.

Here's a diff to show what your changes might look like:

android {
    defaultConfig {
-        minSdk flutter.minSdkVersion
+        minSdk 24
    }
}

Importing and using

Setup

Import flutter_line_sdk to any place you want to use it in your project:

import 'package:flutter_line_sdk/flutter_line_sdk.dart';

To use the package, you need to set up your channel ID. You can do this by calling the setup method, for example in the main function:

- void main() => runApp(MyApp());
+ void main() {
+   WidgetsFlutterBinding.ensureInitialized();
+   LineSDK.instance.setup("${your_channel_id}").then((_) {
+     print("LineSDK Prepared");
+   });
+   runApp(App());
+ }

This is merely an example. You can call setup any time you want, provided you call it exactly once, before calling any other LINE SDK methods.

To help you get started with this package, we list several basic usage examples below. All available flutter_line_sdk methods are documented on the Dart Packages site.

Login

Now you are ready to let your user log in with LINE.

Get the login result by assigning the value of Future<LoginResult> to a variable. To handle errors gracefully, wrap the invocation in a try...on statement:

void _signIn() async {
  try {
    final result = await LineSDK.instance.login();
    // user id -> result.userProfile?.userId
    // user name -> result.userProfile?.displayName
    // user avatar -> result.userProfile?.pictureUrl
  } on PlatformException catch (e) {
    _showDialog(context, e.toString());
  }
}

By default, login uses ["profile"] as its scope. In this case, when login is done, you have a userProfile value in login result. If you need other scopes, pass them in a list to login. See the Scopes documentation for more.

final result = await LineSDK.instance.login(
    scopes: ["profile", "openid", "email"]
);
// user email, if user set it in LINE and granted your request.
final userEmail = result.accessToken.email;

Although it might be useless, if you do not contain a "profile" scope, userProfile will be a null value.

Logout

try {
  await LineSDK.instance.logout();
} on PlatformException catch (e) {
  print(e.message);
}

Get user profile

try {
  final result = await LineSDK.instance.getProfile();
  // user id -> result.userId
  // user name -> result.displayName
  // user avatar -> result.pictureUrl
} on PlatformException catch (e) {
  print(e.message);
}

Get current stored access token

try {
  final result = await LineSDK.instance.currentAccessToken;
  // access token -> result?.value
} on PlatformException catch (e) {
  print(e.message);
}

If the user isn't logged in, it returns a null. A valid result of this method doesn't necessarily mean the access token itself is valid. It may have expired or been revoked by the user from another device or LINE client.

Verify access token with LINE server

try {
  final result = await LineSDK.instance.verifyAccessToken();
  // result.data is accessible if the token is valid.
} on PlatformException catch (e) {
  print(e.message);
  // token is not valid, or any other error.
}

Refresh current access token

try {
  final result = await LineSDK.instance.refreshToken();
  // access token -> result.value
  // expires duration -> result.expiresIn
} on PlatformException catch (e) {
  print(e.message);
}

Normally, you don't need to refresh access tokens manually, because any API call in LINE SDK will try to refresh the access token automatically when necessary. We do not recommend refreshing access tokens yourself. It's generally easier, more secure, and more future-proof to let the LINE SDK manage access tokens automatically.

Error handling

All APIs can throw a PlatformException with error code and a message. Use this information to identify when an error happens inside the native SDK.

Error codes and messages will vary between iOS and Android. Be sure to read the error definition on iOS and Android to provide better error recovery and user experience on different platforms.

Contributing

If you believe you found a vulnerability or you have an issue related to security, please DO NOT open a public issue. Instead, send us an email at [dl_oss_dev@linecorp.com](mailto:dl_oss_dev@linecorp.com).

Before contributing to this project, please read CONTRIBUTING.md.