Criar conversas com vários turnos (chat) usando a API Gemini

Usando o Gemini API, você pode criar conversas de formato livre em vários turnos. O SDK Firebase AI Logic simplifica o processo gerenciando o estado da conversa. Portanto, ao contrário do generateContent() (ou generateContentStream()), você não precisa armazenar o histórico de conversas por conta própria.

Antes de começar

Clique no seu provedor de Gemini API para conferir o conteúdo e o código específicos do provedor nesta página.

Se ainda não tiver feito isso, conclua o guia de início, que descreve como configurar seu projeto do Firebase, conectar seu app ao Firebase, adicionar o SDK, inicializar o serviço de back-end para o provedor de Gemini API escolhido e criar uma instância de GenerativeModel.

Para testar e iterar comandos e até receber um snippet de código gerado, recomendamos usar Google AI Studio.

Criar uma experiência de chat somente de texto

Antes de testar este exemplo, conclua a seção Antes de começar deste guia para configurar seu projeto e app.
Nessa seção, você também clicará em um botão do provedor Gemini API escolhido para ver o conteúdo específico do provedor nesta página.

Para criar uma conversa multiturno (como um chat), comece inicializando o chat chamando startChat(). Em seguida, use sendMessage() para enviar uma nova mensagem do usuário, que também anexa a mensagem e a resposta ao histórico de chat.

Há duas opções possíveis para role associado ao conteúdo de uma conversa:

  • user: o papel que fornece as instruções. Esse valor é o padrão para chamadas para sendMessage(), e a função gera uma exceção se uma função diferente for transmitida.

  • model: o papel que fornece as respostas. Esse papel pode ser usado ao chamar startChat() com history existente.

Swift

Chame startChat() e sendMessage() para enviar uma mensagem a um novo usuário:


import FirebaseAI

// Initialize the Gemini Developer API backend service
let ai = FirebaseAI.firebaseAI(backend: .googleAI())

// Create a `GenerativeModel` instance with a model that supports your use case
let model = ai.generativeModel(modelName: "gemini-2.0-flash")


// Optionally specify existing chat history
let history = [
  ModelContent(role: "user", parts: "Hello, I have 2 dogs in my house."),
  ModelContent(role: "model", parts: "Great to meet you. What would you like to know?"),
]

// Initialize the chat with optional chat history
let chat = model.startChat(history: history)

// To generate text output, call sendMessage and pass in the message
let response = try await chat.sendMessage("How many paws are in my house?")
print(response.text ?? "No text in response.")

Kotlin

Chame startChat() e sendMessage() para enviar uma mensagem a um novo usuário:

No Kotlin, os métodos neste SDK são funções de suspensão e precisam ser chamados de um escopo de corrotina.

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a model that supports your use case
val model = Firebase.ai(backend = GenerativeBackend.googleAI())
                        .generativeModel("gemini-2.0-flash")


// Initialize the chat
val chat = generativeModel.startChat(
  history = listOf(
    content(role = "user") { text("Hello, I have 2 dogs in my house.") },
    content(role = "model") { text("Great to meet you. What would you like to know?") }
  )
)

val response = chat.sendMessage("How many paws are in my house?")
print(response.text)

Java

Chame startChat() e sendMessage() para enviar uma mensagem a um novo usuário:

Em Java, os métodos neste SDK retornam um ListenableFuture.

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a model that supports your use case
GenerativeModel ai = FirebaseAI.getInstance(GenerativeBackend.googleAI())
        .generativeModel("gemini-2.0-flash");

// Use the GenerativeModelFutures Java compatibility layer which offers
// support for ListenableFuture and Publisher APIs
GenerativeModelFutures model = GenerativeModelFutures.from(ai);


// (optional) Create previous chat history for context
Content.Builder userContentBuilder = new Content.Builder();
userContentBuilder.setRole("user");
userContentBuilder.addText("Hello, I have 2 dogs in my house.");
Content userContent = userContentBuilder.build();

Content.Builder modelContentBuilder = new Content.Builder();
modelContentBuilder.setRole("model");
modelContentBuilder.addText("Great to meet you. What would you like to know?");
Content modelContent = userContentBuilder.build();

List<Content> history = Arrays.asList(userContent, modelContent);

// Initialize the chat
ChatFutures chat = model.startChat(history);

// Create a new user message
Content.Builder messageBuilder = new Content.Builder();
messageBuilder.setRole("user");
messageBuilder.addText("How many paws are in my house?");

Content message = messageBuilder.build();

// Send the message
ListenableFuture<GenerateContentResponse> response = chat.sendMessage(message);
Futures.addCallback(response, new FutureCallback<GenerateContentResponse>() {
    @Override
    public void onSuccess(GenerateContentResponse result) {
        String resultText = result.getText();
        System.out.println(resultText);
    }

    @Override
    public void onFailure(Throwable t) {
        t.printStackTrace();
    }
}, executor);

Web

Chame startChat() e sendMessage() para enviar uma mensagem a um novo usuário:


import { initializeApp } from "firebase/app";
import { getAI, getGenerativeModel, GoogleAIBackend } from "firebase/ai";

// TODO(developer) Replace the following with your app's Firebase configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
  // ...
};

// Initialize FirebaseApp
const firebaseApp = initializeApp(firebaseConfig);

// Initialize the Gemini Developer API backend service
const ai = getAI(firebaseApp, { backend: new GoogleAIBackend() });

// Create a `GenerativeModel` instance with a model that supports your use case
const model = getGenerativeModel(ai, { model: "gemini-2.0-flash" });


async function run() {
  const chat = model.startChat({
    history: [
      {
        role: "user",
        parts: [{ text: "Hello, I have 2 dogs in my house." }],
      },
      {
        role: "model",
        parts: [{ text: "Great to meet you. What would you like to know?" }],
      },
    ],
    generationConfig: {
      maxOutputTokens: 100,
    },
  });

  const msg = "How many paws are in my house?";

  const result = await chat.sendMessage(msg);

  const response = await result.response;
  const text = response.text();
  console.log(text);
}

run();

Dart

Chame startChat() e sendMessage() para enviar uma nova mensagem de usuário:


import 'package:firebase_ai/firebase_ai.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';

// Initialize FirebaseApp
await Firebase.initializeApp(
  options: DefaultFirebaseOptions.currentPlatform,
);

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a model that supports your use case
final model =
      FirebaseAI.googleAI().generativeModel(model: 'gemini-2.0-flash');


final chat = model.startChat();
// Provide a prompt that contains text
final prompt = [Content.text('Write a story about a magic backpack.')];

final response = await chat.sendMessage(prompt);
print(response.text);

Unity

Chame StartChat() e SendMessageAsync() para enviar uma mensagem a um novo usuário:


using Firebase;
using Firebase.AI;

// Initialize the Gemini Developer API backend service
var ai = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI());

// Create a `GenerativeModel` instance with a model that supports your use case
var model = ai.GetGenerativeModel(modelName: "gemini-2.0-flash");


// Optionally specify existing chat history
var history = new [] {
  ModelContent.Text("Hello, I have 2 dogs in my house."),
  new ModelContent("model", new ModelContent.TextPart("Great to meet you. What would you like to know?")),
};

// Initialize the chat with optional chat history
var chat = model.StartChat(history);

// To generate text output, call SendMessageAsync and pass in the message
var response = await chat.SendMessageAsync("How many paws are in my house?");
UnityEngine.Debug.Log(response.Text ?? "No text in response.");

Saiba como escolher um modelo adequado para seu caso de uso e app.

Iterar e editar imagens usando o chat multiturno

Antes de testar este exemplo, conclua a seção Antes de começar deste guia para configurar seu projeto e app.
Nessa seção, você também clicará em um botão do provedor Gemini API escolhido para ver o conteúdo específico do provedor nesta página.

Com o chat com várias interações, é possível iterar com um modelo Gemini nas imagens geradas ou fornecidas.

Crie uma instância GenerativeModel, inclua responseModalities: ["TEXT", "IMAGE"] na configuração do modelo e chame startChat() e sendMessage() para enviar novas mensagens ao usuário.

Swift


import FirebaseAI

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
let generativeModel = FirebaseAI.firebaseAI(backend: .googleAI()).generativeModel(
  modelName: "gemini-2.0-flash-preview-image-generation",
  // Configure the model to respond with text and images
  generationConfig: GenerationConfig(responseModalities: [.text, .image])
)

// Initialize the chat
let chat = model.startChat()

guard let image = UIImage(named: "scones") else { fatalError("Image file not found.") }

// Provide an initial text prompt instructing the model to edit the image
let prompt = "Edit this image to make it look like a cartoon"

// To generate an initial response, send a user message with the image and text prompt
let response = try await chat.sendMessage(image, prompt)

// Inspect the generated image
guard let inlineDataPart = response.inlineDataParts.first else {
  fatalError("No image data in response.")
}
guard let uiImage = UIImage(data: inlineDataPart.data) else {
  fatalError("Failed to convert data to UIImage.")
}

// Follow up requests do not need to specify the image again
let followUpResponse = try await chat.sendMessage("But make it old-school line drawing style")

// Inspect the edited image after the follow up request
guard let followUpInlineDataPart = followUpResponse.inlineDataParts.first else {
  fatalError("No image data in response.")
}
guard let followUpUIImage = UIImage(data: followUpInlineDataPart.data) else {
  fatalError("Failed to convert data to UIImage.")
}

Kotlin


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
val model = Firebase.ai(backend = GenerativeBackend.googleAI()).generativeModel(
    modelName = "gemini-2.0-flash-preview-image-generation",
    // Configure the model to respond with text and images
    generationConfig = generationConfig {
responseModalities = listOf(ResponseModality.TEXT, ResponseModality.IMAGE) }
)

// Provide an image for the model to edit
val bitmap = BitmapFactory.decodeResource(context.resources, R.drawable.scones)

// Create the initial prompt instructing the model to edit the image
val prompt = content {
    image(bitmap)
    text("Edit this image to make it look like a cartoon")
}

// Initialize the chat
val chat = model.startChat()

// To generate an initial response, send a user message with the image and text prompt
var response = chat.sendMessage(prompt)
// Inspect the returned image
var generatedImageAsBitmap = response
    .candidates.first().content.parts.firstNotNullOf { it.asImageOrNull() }

// Follow up requests do not need to specify the image again
response = chat.sendMessage("But make it old-school line drawing style")
generatedImageAsBitmap = response
    .candidates.first().content.parts.firstNotNullOf { it.asImageOrNull() }

Java


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
GenerativeModel ai = FirebaseAI.getInstance(GenerativeBackend.googleAI()).generativeModel(
    "gemini-2.0-flash-preview-image-generation",
    // Configure the model to respond with text and images
    new GenerationConfig.Builder()
        .setResponseModalities(Arrays.asList(ResponseModality.TEXT, ResponseModality.IMAGE))
        .build()
);

GenerativeModelFutures model = GenerativeModelFutures.from(ai);

// Provide an image for the model to edit
Bitmap bitmap = BitmapFactory.decodeResource(resources, R.drawable.scones);

// Initialize the chat
ChatFutures chat = model.startChat();

// Create the initial prompt instructing the model to edit the image
Content prompt = new Content.Builder()
        .setRole("user")
        .addImage(bitmap)
        .addText("Edit this image to make it look like a cartoon")
        .build();

// To generate an initial response, send a user message with the image and text prompt
ListenableFuture<GenerateContentResponse> response = chat.sendMessage(prompt);
// Extract the image from the initial response
ListenableFuture<@Nullable Bitmap> initialRequest = Futures.transform(response, result -> {
    for (Part part : result.getCandidates().get(0).getContent().getParts()) {
        if (part instanceof ImagePart) {
            ImagePart imagePart = (ImagePart) part;
            return imagePart.getImage();
        }
    }
    return null;
}, executor);

// Follow up requests do not need to specify the image again
ListenableFuture<GenerateContentResponse> modelResponseFuture = Futures.transformAsync(
        initialRequest,
        generatedImage -> {
            Content followUpPrompt = new Content.Builder()
                    .addText("But make it old-school line drawing style")
                    .build();
            return chat.sendMessage(followUpPrompt);
        },
        executor);

// Add a final callback to check the reworked image
Futures.addCallback(modelResponseFuture, new FutureCallback<GenerateContentResponse>() {
    @Override
    public void onSuccess(GenerateContentResponse result) {
        for (Part part : result.getCandidates().get(0).getContent().getParts()) {
            if (part instanceof ImagePart) {
                ImagePart imagePart = (ImagePart) part;
                Bitmap generatedImageAsBitmap = imagePart.getImage();
                break;
            }
        }
    }

    @Override
    public void onFailure(Throwable t) {
        t.printStackTrace();
    }
}, executor);

Web


import { initializeApp } from "firebase/app";
import { getAI, getGenerativeModel, GoogleAIBackend, ResponseModality } from "firebase/ai";

// TODO(developer) Replace the following with your app's Firebase configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
  // ...
};

// Initialize FirebaseApp
const firebaseApp = initializeApp(firebaseConfig);

// Initialize the Gemini Developer API backend service
const ai = getAI(firebaseApp, { backend: new GoogleAIBackend() });

// Create a `GenerativeModel` instance with a model that supports your use case
const model = getGenerativeModel(ai, {
  model: "gemini-2.0-flash-preview-image-generation",
  // Configure the model to respond with text and images
  generationConfig: {
    responseModalities: [ResponseModality.TEXT, ResponseModality.IMAGE],
  },
});

// Prepare an image for the model to edit
async function fileToGenerativePart(file) {
  const base64EncodedDataPromise = new Promise((resolve) => {
    const reader = new FileReader();
    reader.onloadend = () => resolve(reader.result.split(',')[1]);
    reader.readAsDataURL(file);
  });
  return {
    inlineData: { data: await base64EncodedDataPromise, mimeType: file.type },
  };
}

const fileInputEl = document.querySelector("input[type=file]");
const imagePart = await fileToGenerativePart(fileInputEl.files[0]);

// Provide an initial text prompt instructing the model to edit the image
const prompt = "Edit this image to make it look like a cartoon";

// Initialize the chat
const chat = model.startChat();

// To generate an initial response, send a user message with the image and text prompt
const result = await chat.sendMessage([prompt, imagePart]);

// Request and inspect the generated image
try {
  const inlineDataParts = result.response.inlineDataParts();
  if (inlineDataParts?.[0]) {
    // Inspect the generated image
    const image = inlineDataParts[0].inlineData;
    console.log(image.mimeType, image.data);
  }
} catch (err) {
  console.error('Prompt or candidate was blocked:', err);
}

// Follow up requests do not need to specify the image again
const followUpResult = await chat.sendMessage("But make it old-school line drawing style");

// Request and inspect the returned image
try {
  const followUpInlineDataParts = followUpResult.response.inlineDataParts();
  if (followUpInlineDataParts?.[0]) {
    // Inspect the generated image
    const followUpImage = followUpInlineDataParts[0].inlineData;
    console.log(followUpImage.mimeType, followUpImage.data);
  }
} catch (err) {
  console.error('Prompt or candidate was blocked:', err);
}

Dart


import 'package:firebase_ai/firebase_ai.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';

await Firebase.initializeApp(
  options: DefaultFirebaseOptions.currentPlatform,
);

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
final model = FirebaseAI.googleAI().generativeModel(
  model: 'gemini-2.0-flash-preview-image-generation',
  // Configure the model to respond with text and images
  generationConfig: GenerationConfig(responseModalities: [ResponseModality.text, ResponseModality.image]),
);

// Prepare an image for the model to edit
final image = await File('scones.jpg').readAsBytes();
final imagePart = InlineDataPart('image/jpeg', image);

// Provide an initial text prompt instructing the model to edit the image
final prompt = TextPart("Edit this image to make it look like a cartoon");

// Initialize the chat
final chat = model.startChat();

// To generate an initial response, send a user message with the image and text prompt
final response = await chat.sendMessage([
  Content.multi([prompt,imagePart])
]);

// Inspect the returned image
if (response.inlineDataParts.isNotEmpty) {
  final imageBytes = response.inlineDataParts[0].bytes;
  // Process the image
} else {
  // Handle the case where no images were generated
  print('Error: No images were generated.');
}

// Follow up requests do not need to specify the image again
final followUpResponse = await chat.sendMessage([
  Content.text("But make it old-school line drawing style")
]);

// Inspect the returned image
if (followUpResponse.inlineDataParts.isNotEmpty) {
  final followUpImageBytes = response.inlineDataParts[0].bytes;
  // Process the image
} else {
  // Handle the case where no images were generated
  print('Error: No images were generated.');
}

Unity


using Firebase;
using Firebase.AI;

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
var model = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI()).GetGenerativeModel(
  modelName: "gemini-2.0-flash-preview-image-generation",
  // Configure the model to respond with text and images
  generationConfig: new GenerationConfig(
    responseModalities: new[] { ResponseModality.Text, ResponseModality.Image })
);

// Prepare an image for the model to edit
var imageFile = System.IO.File.ReadAllBytes(System.IO.Path.Combine(
  UnityEngine.Application.streamingAssetsPath, "scones.jpg"));
var image = ModelContent.InlineData("image/jpeg", imageFile);

// Provide an initial text prompt instructing the model to edit the image
var prompt = ModelContent.Text("Edit this image to make it look like a cartoon.");

// Initialize the chat
var chat = model.StartChat();

// To generate an initial response, send a user message with the image and text prompt
var response = await chat.SendMessageAsync(new [] { prompt, image });

// Inspect the returned image
var imageParts = response.Candidates.First().Content.Parts
                         .OfType<ModelContent.InlineDataPart>()
                         .Where(part => part.MimeType == "image/png");
// Load the image into a Unity Texture2D object
UnityEngine.Texture2D texture2D = new(2, 2);
if (texture2D.LoadImage(imageParts.First().Data.ToArray())) {
  // Do something with the image
}

// Follow up requests do not need to specify the image again
var followUpResponse = await chat.SendMessageAsync("But make it old-school line drawing style");

// Inspect the returned image
var followUpImageParts = followUpResponse.Candidates.First().Content.Parts
                         .OfType<ModelContent.InlineDataPart>()
                         .Where(part => part.MimeType == "image/png");
// Load the image into a Unity Texture2D object
UnityEngine.Texture2D followUpTexture2D = new(2, 2);
if (followUpTexture2D.LoadImage(followUpImageParts.First().Data.ToArray())) {
  // Do something with the image
}

Saiba como escolher um modelo adequado para seu caso de uso e app.

Transmitir a resposta

Antes de testar este exemplo, conclua a seção Antes de começar deste guia para configurar seu projeto e app.
Nessa seção, você também clicará em um botão do provedor Gemini API escolhido para ver o conteúdo específico do provedor nesta página.

É possível alcançar interações mais rápidas sem esperar pelo resultado completo da geração do modelo e, em vez disso, usar o streaming para processar resultados parciais. Para transmitir a resposta, chame sendMessageStream().



O que mais você pode fazer?

Testar outros recursos

Saiba como controlar a geração de conteúdo

Você também pode testar comandos e configurações de modelo e até mesmo receber um snippet de código gerado usando Google AI Studio.

Saiba mais sobre os modelos compatíveis

Saiba mais sobre os modelos disponíveis para vários casos de uso e as cotas e o preço.


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