使用 Gemini API 從文字提示生成文字

使用 Vertex AI in Firebase SDK 從應用程式呼叫 Gemini API 時,您可以提示 Gemini 模型根據純文字輸入內容產生文字。

事前準備

如果您尚未完成,請參閱入門指南,瞭解如何設定 Firebase 專案、將應用程式連結至 Firebase、新增 SDK、初始化 Vertex AI 服務,以及建立 GenerativeModel 例項。

從純文字輸入內容生成文字

請先完成本指南的「事前準備」一節,再嘗試使用這個範例。

Swift

您可以呼叫 generateContent(),根據只包含文字的提示要求產生文字:

import FirebaseVertexAI

// Initialize the Vertex AI service
let vertex = VertexAI.vertexAI()

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

// Provide a prompt that contains text
let prompt = "Write a story about a magic backpack."

// To generate text output, call generateContent with the text input
let response = try await model.generateContent(prompt)
print(response.text ?? "No text in response.")

Kotlin

您可以呼叫 generateContentStream(),根據只包含文字的提示要求產生文字:

對於 Kotlin,這個 SDK 中的函式為暫停函式,需要從 協同程式範圍中呼叫。
// Initialize the Vertex AI service and create a `GenerativeModel` instance
// Specify a model that supports your use case
val generativeModel = Firebase.vertexAI.generativeModel("gemini-2.0-flash")

// Provide a prompt that contains text
val prompt = "Write a story about a magic backpack."

// To generate text output, call generateContent with the text input
val response = generativeModel.generateContent(prompt)
print(response.text)

Java

您可以呼叫 generateContentStream(),根據只包含文字的提示要求產生文字:

對於 Java,這個 SDK 中的各個方法會傳回 ListenableFuture
// Initialize the Vertex AI service and create a `GenerativeModel` instance
// Specify a model that supports your use case
GenerativeModel gm = FirebaseVertexAI.getInstance()
        .generativeModel("gemini-2.0-flash");
GenerativeModelFutures model = GenerativeModelFutures.from(gm);

// Provide a prompt that contains text
Content prompt = new Content.Builder()
    .addText("Write a story about a magic backpack.")
    .build();

// To generate text output, call generateContent with the text input
ListenableFuture<GenerateContentResponse> response = model.generateContent(prompt);
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

您可以呼叫 generateContent(),根據只包含文字的提示要求產生文字:

import { initializeApp } from "firebase/app";
import { getVertexAI, getGenerativeModel } from "firebase/vertexai";

// 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 Vertex AI service
const vertexAI = getVertexAI(firebaseApp);

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

// Wrap in an async function so you can use await
async function run() {
  // Provide a prompt that contains text
  const prompt = "Write a story about a magic backpack."

  // To generate text output, call generateContent with the text input
  const result = await model.generateContent(prompt);

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

run();

Dart

您可以呼叫 generateContent(),根據只包含文字的提示要求產生文字:

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

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

// Initialize the Vertex AI service and create a `GenerativeModel` instance
// Specify a model that supports your use case
final model =
      FirebaseVertexAI.instance.generativeModel(model: 'gemini-2.0-flash');

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

// To generate text output, call generateContent with the text input
final response = await model.generateContent(prompt);
print(response.text);

瞭解如何選擇適合用途和應用程式的模型,以及選用的位置

逐句顯示回應

請先完成本指南的「事前準備」一節,再嘗試使用這個範例。

您可以不等待模型產生的完整結果,改用串流處理部分結果,以便加快互動速度。如要串流回應,請呼叫 generateContentStream



你還可以做些什麼?

試用其他功能

瞭解如何控管內容產生作業

您也可以使用 Vertex AI Studio 實驗提示和模型設定。

進一步瞭解支援的型號

瞭解可用於各種用途的模型,以及相關配額價格


針對使用 Vertex AI in Firebase 的體驗提供意見回饋