Gemini Developer API

如要存取 Gemini Pro 和 Flash 模型,建議 Android 開發人員使用 Firebase AI 邏輯,使用 Gemini Developer API。您可以開始使用,而且不需要信用卡,還能享有慷慨的免費方案。在使用者族群規模較小時,您可以先驗證整合功能,然後再切換至付費層級,以便擴大規模。

插圖:包含 Firebase Android SDK 的 Android 應用程式。箭頭從 Cloud 環境中的 SDK 指向 Firebase。從 Firebase 開始,另一個箭頭會指向 Gemini Developer API,而這個 API 會連結至 Cloud 中的 Gemini Pro 和 Flash。
圖 1. Firebase AI Logic 整合架構,可存取 Gemini Developer API。

開始使用

您必須先完成幾項操作,才能直接從應用程式與 Gemini API 互動,包括熟悉提示,以及設定 Firebase 和應用程式以使用 SDK。

測試提示

實驗提示可協助您找出 Android 應用程式最合適的措辭、內容和格式。Google AI Studio 是一種 IDE,可用於為應用程式的用途設計原型和提示。

為特定用途設計合適的提示,與其說是科學,不如說是一門藝術,因此實驗至關重要。如要進一步瞭解提示,請參閱 Firebase 說明文件

確認提示內容無誤後,請按一下「<>"」按鈕,取得可新增至程式碼的程式碼片段。

設定 Firebase 專案,並將應用程式連結至 Firebase

準備好從應用程式呼叫 API 後,請按照 Firebase AI Logic 入門指南的「步驟 1」操作說明,在應用程式中設定 Firebase 和 SDK。

新增 Gradle 依附元件

將下列 Gradle 依附元件新增至應用程式模組:

Kotlin

dependencies {
  // ... other androidx dependencies

  // Import the BoM for the Firebase platform
  implementation(platform("com.google.firebase:firebase-bom:33.13.0"))

  // Add the dependency for the Firebase AI Logic library When using the BoM,
  // you don't specify versions in Firebase library dependencies
  implementation("com.google.firebase:firebase-ai")
}

Java

dependencies {
  // Import the BoM for the Firebase platform
  implementation(platform("com.google.firebase:firebase-bom:33.13.0"))

  // Add the dependency for the Firebase AI Logic library When using the BoM,
  // you don't specify versions in Firebase library dependencies
  implementation("com.google.firebase:firebase-ai")

  // Required for one-shot operations (to use `ListenableFuture` from Guava
  // Android)
  implementation("com.google.guava:guava:31.0.1-android")

  // Required for streaming operations (to use `Publisher` from Reactive
  // Streams)
  implementation("org.reactivestreams:reactive-streams:1.0.4")
}

初始化生成式模型

首先,請將 GenerativeModel 例項化並指定模型名稱:

Kotlin

val model = Firebase.ai(backend = GenerativeBackend.googleAI())
                        .generativeModel("gemini-2.0-flash")

Java

GenerativeModel firebaseAI = FirebaseAI.getInstance(GenerativeBackend.googleAI())
        .generativeModel("gemini-2.0-flash");

GenerativeModelFutures model = GenerativeModelFutures.from(firebaseAI);

進一步瞭解可搭配 Gemini Developer API 使用的可用模型。您也可以進一步瞭解如何設定模型參數

透過應用程式與 Gemini Developer API 互動

您已設定 Firebase 和應用程式,以便使用 SDK,現在可以透過應用程式與 Gemini Developer API 互動了。

產生文字

如要產生文字回應,請使用提示呼叫 generateContent()

Kotlin

scope.launch {
  val response = model.generateContent("Write a story about a magic backpack.")
}

Java

Content prompt = new Content.Builder()
    .addText("Write a story about a magic backpack.")
    .build();

ListenableFuture<GenerateContentResponse> response = model.generateContent(prompt);
Futures.addCallback(response, new FutureCallback<GenerateContentResponse>() {
    @Override
    public void onSuccess(GenerateContentResponse result) {
        String resultText = result.getText();
        [...]
    }

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

使用圖片和其他媒體生成文字

您也可以根據包含文字和圖片或其他媒體的提示生成文字。呼叫 generateContent() 時,您可以將媒體做為內嵌資料傳遞。

舉例來說,如要使用位圖,請使用 image 內容類型:

Kotlin

scope.launch {
  val response = model.generateContent(
    content {
      image(bitmap)
      text("what is the object in the picture?")
    }
  )
}

Java

Content content = new Content.Builder()
        .addImage(bitmap)
        .addText("what is the object in the picture?")
        .build();

ListenableFuture<GenerateContentResponse> response = model.generateContent(content);
Futures.addCallback(response, new FutureCallback<GenerateContentResponse>() {
    @Override
    public void onSuccess(GenerateContentResponse result) {
        String resultText = result.getText();
        [...]
    }

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

如要傳送音訊檔案,請使用 inlineData 內容類型:

Kotlin

val contentResolver = applicationContext.contentResolver
val inputStream = contentResolver.openInputStream(audioUri).use { stream ->
    stream?.let {
        val bytes = stream.readBytes()

        val prompt = content {
            inlineData(bytes, "audio/mpeg")  // Specify the appropriate audio MIME type
            text("Transcribe this audio recording.")
        }

        val response = model.generateContent(prompt)
    }
}

Java

ContentResolver resolver = getApplicationContext().getContentResolver();

try (InputStream stream = resolver.openInputStream(audioUri)) {
    File audioFile = new File(new URI(audioUri.toString()));
    int audioSize = (int) audioFile.length();
    byte audioBytes = new byte[audioSize];
    if (stream != null) {
        stream.read(audioBytes, 0, audioBytes.length);
        stream.close();

        // Provide a prompt that includes audio specified earlier and text
        Content prompt = new Content.Builder()
              .addInlineData(audioBytes, "audio/mpeg")  // Specify the appropriate audio MIME type
              .addText("Transcribe what's said in this audio recording.")
              .build();

        // To generate text output, call `generateContent` with the prompt
        ListenableFuture<GenerateContentResponse> response = model.generateContent(prompt);
        Futures.addCallback(response, new FutureCallback<GenerateContentResponse>() {
            @Override
            public void onSuccess(GenerateContentResponse result) {
                String text = result.getText();
                Log.d(TAG, (text == null) ? "" : text);
            }
            @Override
            public void onFailure(Throwable t) {
                Log.e(TAG, "Failed to generate a response", t);
            }
        }, executor);
    } else {
        Log.e(TAG, "Error getting input stream for file.");
        // Handle the error appropriately
    }
} catch (IOException e) {
    Log.e(TAG, "Failed to read the audio file", e);
} catch (URISyntaxException e) {
    Log.e(TAG, "Invalid audio file", e);
}

如要提供影片檔案,請繼續使用 inlineData 內容類型:

Kotlin

val contentResolver = applicationContext.contentResolver
contentResolver.openInputStream(videoUri).use { stream ->
  stream?.let {
    val bytes = stream.readBytes()

    val prompt = content {
        inlineData(bytes, "video/mp4")  // Specify the appropriate video MIME type
        text("Describe the content of this video")
    }

    val response = model.generateContent(prompt)
  }
}

Java

ContentResolver resolver = getApplicationContext().getContentResolver();

try (InputStream stream = resolver.openInputStream(videoUri)) {
    File videoFile = new File(new URI(videoUri.toString()));
    int videoSize = (int) videoFile.length();
    byte[] videoBytes = new byte[videoSize];
    if (stream != null) {
        stream.read(videoBytes, 0, videoBytes.length);
        stream.close();

        // Provide a prompt that includes video specified earlier and text
        Content prompt = new Content.Builder()
                .addInlineData(videoBytes, "video/mp4")
                .addText("Describe the content of this video")
                .build();

        // To generate text output, call generateContent with the prompt
        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);
    }
} catch (IOException e) {
    e.printStackTrace();
} catch (URISyntaxException e) {
    e.printStackTrace();
}

同樣地,您也可以傳遞 PDF (application/pdf) 和純文字 (text/plain) 文件,並將各自的 MIME 類型做為參數傳遞。

多輪對話

您也可以支援多輪對話。使用 startChat() 函式初始化即時通訊。您可以選擇為模型提供訊息記錄。接著呼叫 sendMessage() 函式,即可傳送即時通訊訊息。

Kotlin

val chat = model.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?")   }
    )
)

scope.launch {
   val response = chat.sendMessage("How many paws are in my house?")
}

Java

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);

詳情請參閱 Firebase 說明文件

後續步驟