要在iOS和Android应用程序中使用Amazon Textract，您需要使用AWS Mobile SDK来集成Amazon Textract API。以下是一些基本步骤和示例代码，用于在iOS和Android应用程序中使用Amazon Textract。

iOS应用程序：

1. 创建一个新的iOS应用程序项目。
2. 在Podfile中添加AWS Mobile SDK的依赖项。确保Podfile中包含以下内容：

platform :ios, '10.0'
target 'YourApp' do
  use_frameworks!
  pod 'AWSMobileClient'
  pod 'AWSTextract'
end

3. 运行pod install命令以安装所需的依赖项。
4. 在AppDelegate.swift文件中导入必要的AWSMobileClient和AWSTextract库：

import AWSMobileClient
import AWSTextract

5. 在didFinishLaunchingWithOptions方法中，添加以下代码以初始化AWSMobileClient：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
  // Initialize AWSMobileClient
  AWSMobileClient.default().initialize { (userState, error) in
    guard error == nil else {
      print("Error initializing AWSMobileClient. \(error!.localizedDescription)")
      return
    }
    print("AWSMobileClient initialized successfully.")
  }

  return true
}

6. 在需要使用Amazon Textract的地方，添加以下代码以调用Amazon Textract API：

import AWSTextract

func callTextractAPI() {
  let textract = AWSTextract.default()

  let request = AWSTextractDetectDocumentTextRequest()
  request?.document = AWSTextractDocument()
  request?.document?.s3Object = AWSTextractS3Object()
  request?.document?.s3Object?.bucket = "your-bucket-name"
  request?.document?.s3Object?.name = "your-document-name"

  textract.detectDocumentText(request!) { (response, error) in
    if let error = error {
      print("Error calling Amazon Textract API. \(error.localizedDescription)")
      return
    }

    if let text = response?.blocks?.filter({ $0.blockType == .word }).map({ $0.text }) {
      print("Extracted text: \(text.joined(separator: " "))")
    }
  }
}

Android应用程序：

1. 创建一个新的Android应用程序项目。
2. 在app/build.gradle文件的dependencies块中添加AWS Mobile SDK库的依赖项。确保dependencies块中包含以下内容：

implementation 'com.amazonaws:aws-android-sdk-mobile-client:2.16.4'
implementation 'com.amazonaws:aws-android-sdk-textract:2.16.4'

3. 在MainActivity.java文件中导入必要的AWSMobileClient和AWSTextract库：

import com.amazonaws.mobile.client.AWSMobileClient;
import com.amazonaws.services.textract.AmazonTextractClient;
import com.amazonaws.services.textract.model.*;

import java.util.List;

4. 在onCreate方法中，添加以下代码以初始化AWSMobileClient：

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  // Initialize AWSMobileClient
  AWSMobileClient.getInstance().initialize(getApplicationContext(), new AWSStartupHandler() {
    @Override
    public void onComplete(AWSStartupResult awsStartupResult) {
      Log.d("MainActivity", "AWSMobileClient initialized successfully.");
    }
  }).execute();
}

5. 在需要使用Amazon Textract的地方，添加以下代码以调用Amazon Textract API：

import com.amazonaws.services.textract.AmazonTextractClient;
import com.amazonaws.services.textract.model.*;

public class MainActivity extends AppCompatActivity {
  private AmazonTextractClient textractClient;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Initialize AmazonTextractClient
    textractClient = new AmazonTextractClient(AWSMobileClient.getInstance().getCredentialsProvider());

    // Call Amazon Textract API
    DetectDocumentTextRequest request = new DetectDocumentTextRequest()
      .withDocument(new Document()
        .withS3Object(new S3Object()
          .withBucket("your-bucket-name")
          .withName("your-document-name")
        )
      );

    DetectDocumentTextResult result = textractClient.detectDocumentText(request);

    List blocks = result.getBlocks();
    List extractedText = blocks.stream()
      .filter