使用 Intent 从 FTP 服务器下载文本文件。

Question

我正在使用 ftp 连接从服务器下载文本文件。 但不幸的是我得到了例外：

android.content.ActivityNotFoundException: No Activity found to handle Intent { act=android.intent.action.PICK dat=64.78.178.19 typ=vnd.android.cursor.dir/lysesoft.andftp.uri (has extras) }

我也在 manifest.xml 中定义了活动。

下面是我的清单文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.saltriver.hourdoc"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.INTERNET"/>


<application android:icon="@drawable/ic_launcher" android:label="@string/app_name">
    <activity android:name=".HourdocActivity"
              android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

</application>

下载文本文件的代码。

public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

   Button downloadFilesButton = (Button) findViewById(R.id.button_download_files_id);
    downloadFilesButton.setOnClickListener(new View.OnClickListener()
    {
  public void onClick(View v) 
  {
    Intent intent = new Intent();
    intent.setAction(Intent.ACTION_PICK);
    // FTP URL (Starts with ftp://, sftp://, ftps:// or scp:// followed by hostname and port).
    Uri ftpUri = Uri.parse(ConstantCodes.ftphost);
    intent.setDataAndType(ftpUri, ConstantCodes.ftpuri);
    // Download
    intent.putExtra("command_type", "download");
    // FTP credentials (optional)
    intent.putExtra("ftp_username", ConstantCodes.userid);
    intent.putExtra("ftp_password", ConstantCodes.pwd);
    //intent.putExtra("ftp_keyfile", "/sdcard/dsakey.txt");
    //intent.putExtra("ftp_keypass", "optionalkeypassword");
    // FTP settings (optional)
    intent.putExtra("ftp_pasv", "true");
    //intent.putExtra("ftp_resume", "true");
    //intent.putExtra("ftp_encoding", "UTF-8");
    //intent.putExtra("ftps_mode", "implicit");
    // Activity title
    intent.putExtra("progress_title", "Downloading files ...");
    // Remote files to download.
    intent.putExtra("remote_file1",  ConstantCodes.ftp_remotefile1);
    //intent.putExtra("remote_file2", "/remotefolder/subfolder/file2.zip");
    // Target local folder where files will be downloaded.
    intent.putExtra("local_folder",  ConstantCodes.localfolder_path);  
    intent.putExtra("close_ui", "true");  
    startActivityForResult(intent,ConstantCodes.DOWNLOAD_FILES_REQUEST);
  }
    });
}

protected void onActivityResult(int requestCode, int resultCode, Intent intent) 
 {
Log.i(TAG, "Result: "+resultCode+ " from request: "+requestCode);
if (intent != null)
{
  String transferredBytesStr = intent.getStringExtra("TRANSFERSIZE");
  String transferTimeStr = intent.getStringExtra("TRANSFERTIME");
  Log.i(TAG, "Transfer status: " + intent.getStringExtra("TRANSFERSTATUS"));
  Log.i(TAG, "Transfer amount: " + intent.getStringExtra("TRANSFERAMOUNT") + " file(s)");
  Log.i(TAG, "Transfer size: " + transferredBytesStr + " bytes");
  Log.i(TAG, "Transfer time: " + transferTimeStr + " milliseconds");
  // Compute transfer rate.
  if ((transferredBytesStr != null) && (transferTimeStr != null))
  {
    try
    {
      long transferredBytes = Long.parseLong(transferredBytesStr);
      long transferTime = Long.parseLong(transferTimeStr);
      double transferRate = 0.0;
      if (transferTime > 0) transferRate = ((transferredBytes) * 1000.0) / (transferTime * 1024.0);
      Log.i(TAG, "Transfer rate: " + transferRate + " KB/s");
    } 
    catch (NumberFormatException e)
    {
       // Cannot parse string.
     }
   }
 }
}

建议我哪里做错了。

Answer 1

我给你找到了一些东西。检查这个GoogleCode 示例项目。它非常适合我。他们正在使用以下类实现下载功能

DownloaderThread.java

public class DownloaderThread extends Thread
{
    // constants
    private static final int DOWNLOAD_BUFFER_SIZE = 4096;

    // instance variables
    private AndroidFileDownloader parentActivity;
    private String downloadUrl;

    /**
     * Instantiates a new DownloaderThread object.
     * @param parentActivity Reference to AndroidFileDownloader activity.
     * @param inUrl String representing the URL of the file to be downloaded.
     */
    public DownloaderThread(AndroidFileDownloader inParentActivity, String inUrl)
    {
        downloadUrl = "";
        if(inUrl != null)
        {
            downloadUrl = inUrl;
        }
        parentActivity = inParentActivity;
    }

    /**
     * Connects to the URL of the file, begins the download, and notifies the
     * AndroidFileDownloader activity of changes in state. Writes the file to
     * the root of the SD card.
     */
    @Override
    public void run()
    {
        URL url;
        URLConnection conn;
        int fileSize, lastSlash;
        String fileName;
        BufferedInputStream inStream;
        BufferedOutputStream outStream;
        File outFile;
        FileOutputStream fileStream;
        Message msg;

        // we're going to connect now
        msg = Message.obtain(parentActivity.activityHandler,
                AndroidFileDownloader.MESSAGE_CONNECTING_STARTED,
                0, 0, downloadUrl);
        parentActivity.activityHandler.sendMessage(msg);

        try
        {
            url = new URL(downloadUrl);
            conn = url.openConnection();
            conn.setUseCaches(false);
            fileSize = conn.getContentLength();

            // get the filename
            lastSlash = url.toString().lastIndexOf('/');
            fileName = "file.bin";
            if(lastSlash >=0)
            {
                fileName = url.toString().substring(lastSlash + 1);
            }
            if(fileName.equals(""))
            {
                fileName = "file.bin";
            }

            // notify download start
            int fileSizeInKB = fileSize / 1024;
            msg = Message.obtain(parentActivity.activityHandler,
                    AndroidFileDownloader.MESSAGE_DOWNLOAD_STARTED,
                    fileSizeInKB, 0, fileName);
            parentActivity.activityHandler.sendMessage(msg);

            // start download
            inStream = new BufferedInputStream(conn.getInputStream());
            outFile = new File(Environment.getExternalStorageDirectory() + "/" + fileName);
            fileStream = new FileOutputStream(outFile);
            outStream = new BufferedOutputStream(fileStream, DOWNLOAD_BUFFER_SIZE);
            byte[] data = new byte[DOWNLOAD_BUFFER_SIZE];
            int bytesRead = 0, totalRead = 0;
            while(!isInterrupted() && (bytesRead = inStream.read(data, 0, data.length)) >= 0)
            {
                outStream.write(data, 0, bytesRead);

                // update progress bar
                totalRead += bytesRead;
                int totalReadInKB = totalRead / 1024;
                msg = Message.obtain(parentActivity.activityHandler,
                        AndroidFileDownloader.MESSAGE_UPDATE_PROGRESS_BAR,
                        totalReadInKB, 0);
                parentActivity.activityHandler.sendMessage(msg);
            }

            outStream.close();
            fileStream.close();
            inStream.close();

            if(isInterrupted())
            {
                // the download was canceled, so let's delete the partially downloaded file
                outFile.delete();
            }
            else
            {
                // notify completion
                msg = Message.obtain(parentActivity.activityHandler,
                        AndroidFileDownloader.MESSAGE_DOWNLOAD_COMPLETE);
                parentActivity.activityHandler.sendMessage(msg);
            }
        }
        catch(MalformedURLException e)
        {
            String errMsg = parentActivity.getString(R.string.error_message_bad_url);
            msg = Message.obtain(parentActivity.activityHandler,
                    AndroidFileDownloader.MESSAGE_ENCOUNTERED_ERROR,
                    0, 0, errMsg);
            parentActivity.activityHandler.sendMessage(msg);
        }
        catch(FileNotFoundException e)
        {
            String errMsg = parentActivity.getString(R.string.error_message_file_not_found);
            msg = Message.obtain(parentActivity.activityHandler,
                    AndroidFileDownloader.MESSAGE_ENCOUNTERED_ERROR,
                    0, 0, errMsg);
            parentActivity.activityHandler.sendMessage(msg); 
        }
        catch(Exception e)
        {
            String errMsg = parentActivity.getString(R.string.error_message_general);
            msg = Message.obtain(parentActivity.activityHandler,
                    AndroidFileDownloader.MESSAGE_ENCOUNTERED_ERROR,
                    0, 0, errMsg);
            parentActivity.activityHandler.sendMessage(msg); 
        }
    }

}

更新

或者您可以简单地将以下代码用于Upload 和Download 进程。

package com.resource.util;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * This class is used to upload a file to a FTP server.
 *
 * @author Muthu
 */
public class FileUpload
{

   /**
    * Upload a file to a FTP server. A FTP URL is generated with the
    * following syntax:
    * ftp://user:password@host:port/filePath;type=i.
    *
    * @param ftpServer , FTP server address (optional port ':portNumber').
    * @param user , Optional user name to login.
    * @param password , Optional password for user.
    * @param fileName , Destination file name on FTP server (with optional
    *            preceding relative path, e.g. "myDir/myFile.txt").
    * @param source , Source file to upload.
    * @throws MalformedURLException, IOException on error.
    */
   public void upload( String ftpServer, String user, String password,
         String fileName, File source ) throws MalformedURLException,
         IOException
   {
      if (ftpServer != null && fileName != null && source != null)
      {
         StringBuffer sb = new StringBuffer( "ftp://" );
         // check for authentication else assume its anonymous access.
         if (user != null && password != null)
         {
            sb.append( user );
            sb.append( ':' );
            sb.append( password );
            sb.append( '@' );
         }
         sb.append( ftpServer );
         sb.append( '/' );
         sb.append( fileName );
         /*
          * type ==> a=ASCII mode, i=image (binary) mode, d= file directory
          * listing
          */
         sb.append( ";type=i" );

         BufferedInputStream bis = null;
         BufferedOutputStream bos = null;
         try
         {
            URL url = new URL( sb.toString() );
            URLConnection urlc = url.openConnection();

            bos = new BufferedOutputStream( urlc.getOutputStream() );
            bis = new BufferedInputStream( new FileInputStream( source ) );

            int i;
            // read byte by byte until end of stream
            while ((i = bis.read()) != -1)
            {
               bos.write( i );
            }
         }
         finally
         {
            if (bis != null)
               try
               {
                  bis.close();
               }
               catch (IOException ioe)
               {
                  ioe.printStackTrace();
               }
            if (bos != null)
               try
               {
                  bos.close();
               }
               catch (IOException ioe)
               {
                  ioe.printStackTrace();
               }
         }
      }
      else
      {
         System.out.println( "Input not available." );
      }
   }

   /**
    * Download a file from a FTP server. A FTP URL is generated with the
    * following syntax:
    * ftp://user:password@host:port/filePath;type=i.
    *
    * @param ftpServer , FTP server address (optional port ':portNumber').
    * @param user , Optional user name to login.
    * @param password , Optional password for user.
    * @param fileName , Name of file to download (with optional preceeding
    *            relative path, e.g. one/two/three.txt).
    * @param destination , Destination file to save.
    * @throws MalformedURLException, IOException on error.
    */
   public void download( String ftpServer, String user, String password,
         String fileName, File destination ) throws MalformedURLException,
         IOException
   {
      if (ftpServer != null && fileName != null && destination != null)
      {
         StringBuffer sb = new StringBuffer( "ftp://" );
         // check for authentication else assume its anonymous access.
         if (user != null && password != null)
         {
            sb.append( user );
            sb.append( ':' );
            sb.append( password );
            sb.append( '@' );
         }
         sb.append( ftpServer );
         sb.append( '/' );
         sb.append( fileName );
         /*
          * type ==> a=ASCII mode, i=image (binary) mode, d= file directory
          * listing
          */
         sb.append( ";type=i" );
         BufferedInputStream bis = null;
         BufferedOutputStream bos = null;
         try
         {
            URL url = new URL( sb.toString() );
            URLConnection urlc = url.openConnection();

            bis = new BufferedInputStream( urlc.getInputStream() );
            bos = new BufferedOutputStream( new FileOutputStream(
                  destination.getName() ) );

            int i;
            while ((i = bis.read()) != -1)
            {
               bos.write( i );
            }
         }
         finally
         {
            if (bis != null)
               try
               {
                  bis.close();
               }
               catch (IOException ioe)
               {
                  ioe.printStackTrace();
               }
            if (bos != null)
               try
               {
                  bos.close();
               }
               catch (IOException ioe)
               {
                  ioe.printStackTrace();
               }
         }
      }
      else
      {
         System.out.println( "Input not available" );
      }
   }
}

从上面的代码download() 方法可以为您提供所需的任何内容。

Answer 2

我使用库 Download Commons Net 是最好的库之一，它非常适合上传或下载