从Android App打开PDF

Question

我正在使用自定义类从我的Android应用程序打开PDF。 它检查是否已经下载了PDF，然后使用现有的PDF Viewer应用程序打开PDF。 如果没有pdf查看器应用程序，则尝试使用google docs打开pdf。

在将Android Studio 2.2.3从2.2.3升级到Build Tool Version从24升级到25之前，该类运行良好。目标SDK仍是API24。无法找出问题的确切根源。

PDF类别 ：

public class PDFTools {
private static final String GOOGLE_DRIVE_PDF_READER_PREFIX = "http://docs.google.com/viewer?url=";
private static final String PDF_MIME_TYPE = "application/pdf";
private static final String HTML_MIME_TYPE = "text/html";

/**
 * If a PDF reader is installed, download the PDF file and open it in a reader.
 * Otherwise ask the user if he/she wants to view it in the Google Drive online PDF reader.<br />
 * <br />
 * <b>BEWARE:</b> This method
 * @param context
 * @param pdfUrl
 * @return
 */
public static void showPDFUrl( final Context context, final String pdfUrl ) {
    if ( isPDFSupported( context ) ) {
        downloadAndOpenPDF(context, pdfUrl);
    } else {
        askToOpenPDFThroughGoogleDrive( context, pdfUrl );
    }
}

/**
 * Downloads a PDF with the Android DownloadManager and opens it with an installed PDF reader app.
 * @param context
 * @param pdfUrl
 */

public static void downloadAndOpenPDF(final Context context, final String pdfUrl) {
    // Get filename
    final String filename = pdfUrl.substring( pdfUrl.lastIndexOf( "/" ) + 1 );
    // The place where the downloaded PDF file will be put
    final File tempFile = new File( context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS), filename );
    if ( tempFile.exists() ) {
        // If we have downloaded the file before, just go ahead and show it.
        Uri uri = null;
        File docPath = new File(context.getExternalFilesDir(null), "Download");
        File newFile = new File(docPath, filename);

        uri = FileProvider.getUriForFile( context, BuildConfig.APPLICATION_ID + ".provider", newFile );

        openPDF( context, uri);
        return;
    }

    // Show progress dialog while downloading
    final ProgressDialog progress = ProgressDialog.show( context, context.getString( R.string.pdf_show_local_progress_title ),
            context.getString( R.string.message_please_wait ), true );

    // Create the download request
    DownloadManager.Request r = new DownloadManager.Request( Uri.parse( pdfUrl ) );
    r.setDestinationInExternalFilesDir( context, Environment.DIRECTORY_DOWNLOADS, filename );
    final DownloadManager dm = (DownloadManager) context.getSystemService( Context.DOWNLOAD_SERVICE );
    BroadcastReceiver onComplete = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if ( !progress.isShowing() ) {
                return;
            }
            context.unregisterReceiver( this );

            progress.dismiss();
            long downloadId = intent.getLongExtra( DownloadManager.EXTRA_DOWNLOAD_ID, -1 );
            Cursor c = dm.query( new DownloadManager.Query().setFilterById( downloadId ) );

            if ( c.moveToFirst() ) {
                int status = c.getInt( c.getColumnIndex( DownloadManager.COLUMN_STATUS ) );
                if ( status == DownloadManager.STATUS_SUCCESSFUL ) {
                    Uri uri = null;
                    try {
                        uri = FileProvider.getUriForFile(context, BuildConfig.APPLICATION_ID + ".provider", tempFile );

                    }catch (IllegalArgumentException iae) {
                        iae.printStackTrace();
                    }
                    if (uri !=null) {
                        openPDF(context, uri);
                    }
                }
            }
            c.close();
        }
    };
    context.registerReceiver( onComplete, new IntentFilter( DownloadManager.ACTION_DOWNLOAD_COMPLETE ) );

    // Enqueue the request
    dm.enqueue( r );
}

/**
 * Show a dialog asking the user if he wants to open the PDF through Google Drive
 * @param context
 * @param pdfUrl
 */
public static void askToOpenPDFThroughGoogleDrive( final Context context, final String pdfUrl ) {
    new AlertDialog.Builder( context )
            .setTitle( R.string.pdf_show_online_dialog_title )
            .setMessage( R.string.pdf_show_online_dialog_question )
            .setNegativeButton( R.string.pdf_show_online_dialog_button_no, null )
            .setPositiveButton( R.string.pdf_show_online_dialog_button_yes, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    openPDFThroughGoogleDrive(context, pdfUrl);
                }
            })
            .show();
}

/**
 * Launches a browser to view the PDF through Google Drive
 * @param context
 * @param pdfUrl
 */
public static void openPDFThroughGoogleDrive(final Context context, final String pdfUrl) {
    Intent i = new Intent( Intent.ACTION_VIEW );
    i.setDataAndType(Uri.parse(GOOGLE_DRIVE_PDF_READER_PREFIX + pdfUrl ), HTML_MIME_TYPE );
    context.startActivity( i );
}
/**
 * Open a local PDF file with an installed reader
 * @param context
 * @param localUri
 */
public static final void openPDF(Context context, Uri localUri ) {
    Intent i = new Intent( Intent.ACTION_VIEW );
    i.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    i.setDataAndType( localUri, PDF_MIME_TYPE );
    context.startActivity( i );
}
/**
 * Checks if any apps are installed that supports reading of PDF files.
 * @param context
 * @return
 */
public static boolean isPDFSupported( Context context ) {
    Intent i = new Intent( Intent.ACTION_VIEW );
    final File tempFile = new File( context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS), "test.pdf" );
    i.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    i.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
    try {
        i.setDataAndType( FileProvider.getUriForFile( context, BuildConfig.APPLICATION_ID + ".provider" ,tempFile ), PDF_MIME_TYPE );
    }catch (IllegalArgumentException iae ) {
    }
    return context.getPackageManager().queryIntentActivities( i, PackageManager.MATCH_DEFAULT_ONLY ).size() > 0;
}

}

它抛出一个错误

java.lang.IllegalArgumentException: Failed to find configured root that contains /storage/emulated/0/Android/data/<PACKAGE>/files/Download/javascript_pdf_version.pdf

我已经从堆栈溢出本身中获取了此样本。 感谢您的帮助。

Answer 1

试试这样的东西下载：

使用RestTemplate的WebService：

public PdfByteArrayObject getPrintjob(String empId) {
    PdfByteArrayObject pdfByteArrayObject = null;
    try {
        getUrl();
        RestTemplate restTemplate = new RestTemplate();            
        restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());

        pdfByteArrayObject = restTemplate.getForObject("pdfURL" + empId, PdfByteArrayObject.class);


    } catch (Exception e) {
      e.printStackTrace();            
      Log.e("webser======", e.toString());
    }
    return pdfByteArrayObject;
}

getUrl方法（用于文件转换和存储）：

public void getUrl() {
    StringBuffer stringBuffer = new StringBuffer();
    String aDataRow = "";
    String aBuffer = "";
    try {
        File serverPath = new File(Environment.getExternalStorageDirectory(), "ServerUrl");

        if (serverPath.exists()) {
            FileInputStream fIn = new FileInputStream(serverPath);
            BufferedReader myReader = new BufferedReader(
                    new InputStreamReader(fIn));

            while ((aDataRow = myReader.readLine()) != null) {
                aBuffer += aDataRow;
            }
            RestUrl = aBuffer;
            Log.e("RestUrl", RestUrl + "--");
            myReader.close();
        } else {
            Log.e("RestUrl", "File not found");
        }

    } catch (IOException e) {
        e.printStackTrace();
    }
    // Toast.makeText(getApplicationContext(),aBuffer,Toast.LENGTH_LONG).show();
}

和对象：

public class PdfByteArrayObject {

private byte[] pdffile;

public byte[] getPdffile() {
    return pdffile;
}

public void setPdffile(byte[] pdffile) {
    this.pdffile = pdffile;
}
}

希望这可以帮助！