要在Android应用中使用AWS Lambda，您需要添加AWS SDK for Android和AWS Lambda的相关依赖。

首先，您需要在您的项目的build.gradle文件中添加AWS SDK for Android的依赖：

dependencies {
    implementation 'com.amazonaws:aws-android-sdk-core:2.18.0'
    implementation 'com.amazonaws:aws-android-sdk-lambda:2.18.0'
}

接下来，您需要在您的代码中创建一个AWSLambdaClient对象，以便与AWS Lambda服务进行交互。以下是一个简单的示例：

import com.amazonaws.auth.CognitoCachingCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.lambda.AWSLambda;
import com.amazonaws.services.lambda.AWSLambdaClient;
import com.amazonaws.services.lambda.model.InvokeRequest;
import com.amazonaws.services.lambda.model.InvokeResult;

public class LambdaExample {
    private static final String AWS_REGION = "your_aws_region";
    private static final String IDENTITY_POOL_ID = "your_identity_pool_id";
    private static final String LAMBDA_FUNCTION_NAME = "your_lambda_function_name";

    public void invokeLambdaFunction() {
        // 创建Cognito身份提供者
        CognitoCachingCredentialsProvider credentialsProvider = new CognitoCachingCredentialsProvider(
                getApplicationContext(),
                IDENTITY_POOL_ID,
                Regions.fromName(AWS_REGION)
        );

        // 创建AWSLambdaClient对象
        AWSLambda lambdaClient = AWSLambdaClient.builder()
                .withRegion(AWS_REGION)
                .withCredentials(new AWSStaticCredentialsProvider(credentialsProvider.getCredentials()))
                .build();

        // 创建InvokeRequest
        InvokeRequest invokeRequest = new InvokeRequest()
                .withFunctionName(LAMBDA_FUNCTION_NAME)
                .withPayload("your_payload");

        // 调用Lambda函数
        InvokeResult invokeResult = lambdaClient.invoke(invokeRequest);
        
        // 处理Lambda函数的响应
        String response = new String(invokeResult.getPayload().array());
        System.out.println("Lambda Function Response: " + response);
    }
}

请注意，上述示例中的your_aws_region，your_identity_pool_id和your_lambda_function_name需要替换为您的实际值。另外，your_payload是您要传递给Lambda函数的有效负载数据。

这样，您就可以在Android应用中使用AWS Lambda了。