使用android异步任务下载并查看内存中的Pdf

<uses-permission android:name="android.permission.INTERNET" />

private class DownloadAndViewPdfTask extends AsyncTask<String, Void, File> {

    @Override
    protected File doInBackground(String... urls) {
        String pdfUrl = urls[0];
        File pdfFile = null;

        try {
            // 下载PDF文件
            URL url = new URL(pdfUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.connect();

            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                InputStream inputStream = connection.getInputStream();
                pdfFile = new File(getCacheDir(), "sample.pdf");
                FileOutputStream outputStream = new FileOutputStream(pdfFile);

                byte[] buffer = new byte[1024];
                int bytesRead;
                while ((bytesRead = inputStream.read(buffer)) != -1) {
                    outputStream.write(buffer, 0, bytesRead);
                }

                outputStream.close();
                inputStream.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

        return pdfFile;
    }

    @Override
    protected void onPostExecute(File pdfFile) {
        if (pdfFile != null) {
            // 在内存中查看PDF文件
            Intent intent = new Intent(Intent.ACTION_VIEW);
            intent.setDataAndType(Uri.fromFile(pdfFile), "application/pdf");
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

            try {
                startActivity(intent);
            } catch (ActivityNotFoundException e) {
                Toast.makeText(getApplicationContext(), "没有找到可用的PDF查看器", Toast.LENGTH_SHORT).show();
            }
        } else {
            Toast.makeText(getApplicationContext(), "下载PDF文件失败", Toast.LENGTH_SHORT).show();
        }
    }
}

String pdfUrl = "https://example.com/sample.pdf";
new DownloadAndViewPdfTask().execute(pdfUrl);