安卓开发地址选择器获取外部储存u盘地址并创建pdf文件并写入数据到pdf文件里

import android.app.Activity;

import android.content.Intent;

import android.net.Uri;

import android.os.Bundle;

import android.os.Environment;

import android.os.storage.StorageManager;

import android.os.storage.StorageVolume;

import android.provider.DocumentsContract;

import android.widget.Toast;

import androidx.annotation.Nullable;

import androidx.appcompat.app.AppCompatActivity;

import androidx.documentfile.provider.DocumentFile;

import com.itextpdf.kernel.pdf.PdfDocument;

import com.itextpdf.kernel.pdf.PdfWriter;

import com.itextpdf.layout.Document;

import com.itextpdf.layout.element.Paragraph;

import java.io.IOException;

import java.io.OutputStream;

public class PdfWriteToUsbActivity extends AppCompatActivity {

    private static final int REQUEST_CODE_OPEN_DIRECTORY = 1;

    private String selectedDirectory;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_pdf_write_to_usb);

        // 打开文档树选择器

        openDirectoryPicker();

    }

    private void openDirectoryPicker() {

        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE);

        startActivityForResult(intent, REQUEST_CODE_OPEN_DIRECTORY);

    }

    @Override

    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {

        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == REQUEST_CODE_OPEN_DIRECTORY && resultCode == Activity.RESULT_OK && data != null) {

            // 获取用户选择的目录的 URI

            selectedDirectory = data.getData().toString();

            // 创建 PDF 文件并写入数据

            createAndWriteToPdf();

        }

    }

    private void createAndWriteToPdf() {

        if (selectedDirectory != null) {

            DocumentFile pickedDir = DocumentFile.fromTreeUri(this, Uri.parse(selectedDirectory));

            if (pickedDir != null && pickedDir.exists() && pickedDir.isDirectory()) {

                // 在选择的目录下创建一个 PDF 文件

                DocumentFile newFile = pickedDir.createFile(“application/pdf”, “new_file.pdf”);

                if (newFile != null && newFile.exists()) {

                    // 写入数据到 PDF 文件

                    writeDataToPdf(newFile);

                } else {

                    // 文件创建失败

                    Toast.makeText(this, “PDF file creation failed”, Toast.LENGTH_SHORT).show();

                }

            }

        } else {

            Toast.makeText(this, “Please select a directory first”, Toast.LENGTH_SHORT).show();

        }

    }

    private void writeDataToPdf(DocumentFile pdfFile) {

        try {

            // 创建 PdfWriter 和 PdfDocument

            OutputStream outputStream = getContentResolver().openOutputStream(pdfFile.getUri());

            PdfWriter pdfWriter = new PdfWriter(outputStream);

            PdfDocument pdfDocument = new PdfDocument(pdfWriter);

            // 创建 Document

            Document document = new Document(pdfDocument);

            // 写入数据到 PDF

            document.add(new Paragraph(“Hello, this is a sample PDF document.”));

            // 关闭 Document

            document.close();

            // 显示成功消息

            Toast.makeText(this, “PDF file created and data written successfully”, Toast.LENGTH_SHORT).show();

        } catch (IOException e) {

            e.printStackTrace();

            // 处理异常

        }

    }

}