使用 Flutter 快速实现聊天应用

dependencies:
  leancloud_official_plugin: ^1.0.0-beta.8   //即时通信插件
  leancloud_storage: ^0.2.9  //数据存储 SDK

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

dependencies {
implementation 'cn.leancloud:storage-android:6.5.11'
implementation 'cn.leancloud:realtime-android:6.5.11'
implementation 'io.reactivex.rxjava2:rxandroid:2.1.1'
}

ConversationQuery query = client.conversationQuery();
await query.find();

query.orderByDescending('updatedAt');

//让查询结果附带一条最新消息
query.includeLastMessage = true;

AVIMOptions.getGlobalOptions().setUnreadNotificationEnabled(true);

client.onUnreadMessageCountUpdated = ({
  Client client,
  Conversation conversation,
}) {
  // conversation.unreadMessageCount 即该 conversation 的未读消息数量
};

List<Message> messages;
try {
//第一次查询成功
  messages = await conversation.queryMessage(
    limit: 10,
  );
} catch (e) {
  print(e);
}

try {
  // 返回的消息一定是时间增序排列，也就是最早的消息一定是第一个
  Message oldMessage = messages.first;
  // 以第一页的最早的消息作为开始，继续向前拉取消息
  List<Message> messages2 = await conversation.queryMessage(
    startTimestamp: oldMessage.sentTimestamp,
    startMessageID: oldMessage.id,
    startClosed: true,
    limit: 10,
  );
} catch (e) {
  print(e);
}

await conversation.updateInfo(attributes: {
  'name': 'New Name',
});

LCFile file = await LCFile.fromPath('message.wav', path);
await file.save();

//发送消息
AudioMessage audioMessage = AudioMessage.from(
  binaryData: file.data,
  format: 'wav',
);
await this.widget.conversation.send(message: audioMessage);

<key>NSMicrophoneUsageDescription</key>
<string>录音功能需要访问麦克风，如果不允许，你将无法在聊天过程中发送语音消息。</string>
   
<key>NSCameraUsageDescription</key>
<string>发送图片功能需要访问您的相机。如果不允许，你将无法在聊天过程中发送图片消息。</string>
   
<key>NSPhotoLibraryUsageDescription</key>
<string>发送图片功能需要访问您的相册。如果不允许，你将无法在聊天过程中发送相册中的图片。</string>

{ "alert": "您有新的消息", "badge": "Increment" }

import Flutter
import LeanCloud
import UserNotifications
@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        do {
            LCApplication.logLevel = .all
            try LCApplication.default.set(
                 id: "你的APPID",
                               key: "你的 APPKey",
                               serverURL: "服务器地址")
            GeneratedPluginRegistrant.register(with: self)
            /*
            register APNs to access token, like this:
            */
            UNUserNotificationCenter.current().getNotificationSettings { (settings) in
                switch settings.authorizationStatus {
                case .authorized:
                    DispatchQueue.main.async {
                        UIApplication.shared.registerForRemoteNotifications()
                    }
                case .notDetermined:
                    UNUserNotificationCenter.current().requestAuthorization(options: [.badge, .alert, .sound]) { (granted, error) in
                        if granted {
                            DispatchQueue.main.async {
                                UIApplication.shared.registerForRemoteNotifications()
                            }
                        }
                    }
                default:
                    break
                }
                _ = LCApplication.default.currentInstallation
            }
            return super.application(application, didFinishLaunchingWithOptions: launchOptions)
        } catch {
            fatalError("\(error)")
        }
    }
    override func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        /*
        set APNs deviceToken and Team ID.
        */
        LCApplication.default.currentInstallation.set(
            deviceToken: deviceToken,
            apnsTeamId: "你的 TeamId")
        /*
        save to LeanCloud.
        */
        LCApplication.default.currentInstallation.save { (result) in
            switch result {
            case .success:
                break
            case .failure(error: let error):
                print(error)
            }
        }
    }
    override func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
        //如果注册推送失败，可以检查 error 信息
        print(error)
    }
}

//保存一条举报信息
LCObject report = LCObject('Report');
report['clientID'] = Global.clientID;   //举报人
report['messageID'] = messageID;   //消息 ID
report['conversationID'] = this.widget.conversation.id;  //会话 ID
report['content'] = _selectedReportList.toString(); //举报内容
await report.save(); //保存举报信息

//下面这个函数粘贴在 LeanCloud 控制台
AV.Cloud.define('_messageReceived', async function(request) {
let fromPeer = request.params.fromPeer;
let toPeersNew = request.params.toPeers;
var query = new AV.Query('BlackList');
query.equalTo('blackedList', fromPeer);
query.containedIn('clientID', toPeersNew);
return query.find().then((results) => {
    if (results.length > 0) {
        var clientID = results[0].get('clientID');
        var index = toPeersNew.indexOf(clientID);
        if (index > -1) {
            toPeersNew.splice(index, 1);
        }
        return {
            toPeers: toPeersNew
        }
    }
    return {
    }
});
})