如需使用 Gemini Pro 和 Flash 模型,我们建议 Android 开发者使用 Firebase AI Logic 来使用 Gemini Developer API。您无需信用卡即可开始使用,并且提供宽裕的免费层级。在对小型用户群进行集成验证后,您可以通过改用付费层级来扩展规模。
使用入门
在直接从应用与 Gemini API 交互之前,您需要先完成一些操作,包括熟悉提示功能,以及设置 Firebase 和应用以使用 SDK。
使用提示进行实验
对提示进行实验有助于您为 Android 应用找到最佳措辞、内容和格式。Google AI Studio 是一个 IDE,可用于为应用的用例设计和开发提示原型。
为您的用例创建合适的提示与其说是科学,不如说是艺术,因此实验至关重要。如需详细了解提示,请参阅 Firebase 文档。
当您对提示满意后,点击“<>”按钮即可获取可添加到代码中的代码段。
设置 Firebase 项目并将您的应用连接到 Firebase
准备好从应用调用 API 后,请按照 Firebase AI 逻辑入门指南的“第 1 步”中的说明,在应用中设置 Firebase 和 SDK。
添加 Gradle 依赖项
将以下 Gradle 依赖项添加到应用模块中:
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,实例化 GenerativeModel
并指定模型名称:
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);
详细了解可与 Gemini Developer API 搭配使用的可用模型。您还可以详细了解如何配置模型参数。
从您的应用与 Gemini Developer API 互动
现在,您已设置 Firebase 和应用以使用该 SDK,接下来就可以从应用与 Gemini Developer API 进行交互了。
生成文本
如需生成文本回答,请使用问题调用 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);
根据图片和其他媒体内容生成文本
您还可以根据包含文字、图片或其他媒体内容的提示生成文本。调用 generateContent()
时,您可以将媒体作为内嵌数据传递。
例如,如需使用位图,请使用 image
内容类型:
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);
如需传递音频文件,请使用 inlineData
内容类型:
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);
}
如需提供视频文件,请继续使用 inlineData
内容类型:
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();
}
同样,您也可以将 PDF (application/pdf
) 和纯文本 (text/plain
) 文档作为参数传递,并将其各自的 MIME 类型作为参数传递。
多轮聊天
您还可以支持多轮对话。使用 startChat()
函数初始化聊天。您可以选择为模型提供消息历史记录。然后,调用 sendMessage()
函数发送聊天消息。
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);
如需了解详情,请参阅 Firebase 文档。
后续步骤
- 查看 GitHub 上的 Android 快速入门 Firebase 示例应用和 Android AI 示例目录。
- 准备将应用用于生产环境,包括设置 Firebase App Check,以保护 Gemini API 免遭未经授权的客户端滥用。
- 如需详细了解 Firebase AI Logic,请参阅 Firebase 文档。