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Installing JavaScript SDK for Data Storage and Instant Messaging

Installing SDK


There are various ways to obtain the SDK, but the recommended approach is to download the latest version through a package dependency management tool


Specify leancloud_storage as dependency in pubspec.yaml:

sdk: flutter
leancloud_storage: ^0.7.10


Specify leancloud_official_plugin as dependency in pubspec.yaml:

sdk: flutter
leancloud_official_plugin: ^1.0.1


dependencies {
implementation 'cn.leancloud:storage-android:8.2.19'
implementation 'cn.leancloud:realtime-android:8.2.19'
implementation 'io.reactivex.rxjava2:rxandroid:2.1.1'


cd ios/
pod update # or $ pod install --repo-update

Initializing Your Project

You can view the credentials of your app by going to Dashboard > Settings > App keys:

  • App ID will be used when you initialize the SDK.
  • App Key will be used when you initialize the SDK on the client side.
  • Master Key will be used when you interact with admin interfaces on trusted environments including your own server and LeanEngine. When you use it, all the permission checks will be skipped. Make sure to keep it private and never use it in the code for the client.

See Domain for setting up the domain.

Initializing LeanStorage

Add this import statement in the Dart code:

import 'package:leancloud_storage/leancloud.dart';

And initialize SDK as follows:

'your-app-id', 'your-app-key',
server: 'https://your_server_url',
queryCache: new LCQueryCache());

Android Permissions

Do not forget to specify required permissions in AndroidManifest.xml:

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Initializing LeanMessage

Import package:leancloud_official_plugin/leancloud_plugin.dart in lib/main.dart of your project:

import 'package:leancloud_official_plugin/leancloud_plugin.dart';

To use the Flutter instant messaging plugin, initialization is required on both the Android and iOS platforms separately.

Android Platform Initialization

First, add the following to the onCreate method of the Application class:

import cn.leancloud.LeanCloud;
import cn.leancloud.LCLogger;

public class MyLeanCloudApp extends FlutterApplication {
public void onCreate() {
LeanCloud.initialize(this, "your-app-id", "your-app-key", "https://your_server_url");

Then, specify the required permissions for the SDK and declare the MyLeanCloudApp class in the AndroidManifest.xml file:

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />


android:name=".MyLeanCloudApp" >

<service android:name="cn.leancloud.push.PushService"/>
<receiver android:name="cn.leancloud.push.LCBroadcastReceiver">
<action android:name="android.intent.action.BOOT_COMPLETED"/>
<action android:name="android.intent.action.USER_PRESENT"/>
<action android:name="" />

iOS 平台初始化

Add the following initialization code to the AppDelegate.swift file:

import Flutter
import LeanCloud

@objc class AppDelegate: FlutterAppDelegate {
override func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
do {
LCApplication.logLevel = .all
try LCApplication.default.set(
id: "your-app-id",
key: "your-app-key",
serverURL: "https://your_server_url")
GeneratedPluginRegistrant.register(with: self)
return super.application(application, didFinishLaunchingWithOptions: launchOptions)
} catch {

Enabling Debug Logs

You can easily trace the problems in your project by turning debug logs on during the development phase. Once enabled, details of every request made by the SDK along with errors will be output to IDE, browser console, or your app's Dashboard > LeanEngine > App logs.




Refer to Swift SDK Setup Guide and Java SDK Setup Guide for information on how to enable debug logs on iOS and Android platforms.

Make sure debug logs are turned off before your app is published. Failure to do so may lead to the exposure of sensitive data.


First of all, make sure you are able to connect to LeanCloud server. You can test it by running the following command:

curl "https://{{host}}/1.1/date"

If everything goes well, it will return the current date:

{ "__type": "Date", "iso": "2020-10-12T06:46:56.000Z" }

Then add the following code into your project:

LCObject testObject = LCObject('TestObject');
testObject['words'] = 'Hello world!';

Save the file and run it.

Then go to your app's Dashboard > LeanStorage > Data > TestObject. If you see the following content, it means that you have correctly installed the SDK.


This guide is written for the latest version of our SDK. If you encounter any error, please first make sure you have the latest version installed.

401 Unauthorized

If you get a 401 error or see the following content in network logs:

"code": 401,
"error": "Unauthorized."

It means that the App ID or App Key might be incorrect or don't match. If you have multiple apps, you might have used the App ID of one app with the App Key of another one, which will lead to such error.

Client Cannot Access the Internet

Make sure you have granted enough permissions for your mobile app.