Android从ftp服务器获取文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.getpkgfromftp.MainActivity" >

    <!-- ip地址 -->

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/ip"
        android:textSize="30sp" />

    <!-- 端口号 -->

    <TextView
        android:id="@+id/pkgRoute"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/port"
        android:textSize="30sp" />

    <!-- 用户名 -->

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:focusable="true"
        android:focusableInTouchMode="true" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/username"
            android:textSize="20sp" />

        <EditText
            android:id="@+id/etUserName"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@android:drawable/edit_text"
            android:hint="@string/username"
            android:text="@string/user"
            android:textSize="20sp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/_suffix"
            android:textSize="20sp" />
    </LinearLayout>

    <!-- 密码 -->

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:focusable="true"
        android:focusableInTouchMode="true" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/pwd"
            android:textSize="20sp" />

        <EditText
            android:id="@+id/etPwd"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@android:drawable/edit_text"
            android:hint="@string/default_pwd"
            android:text="@string/default_pwd"
            android:textSize="20sp" />
    </LinearLayout>

    <Button
        android:id="@+id/btnGet"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/get" />

    <!-- 用来显示ftp服务器里面的文件列表 -->

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </ListView>

</LinearLayout>

package com.example.getpkgfromftp;

import it.sauronsoftware.ftp4j.FTPClient;
import it.sauronsoftware.ftp4j.FTPDataTransferListener;

import java.io.File;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends Activity {
    /** 只需要ip地址，不需要前面的ftp:// */
    private static final String HOST = "";
    private static final int PORT = 21;
    private String USERNAME = "";
    private String PASSWORD = "";

    private ListView listView;
    private ArrayAdapter<String> adapter;

    private FTPClient client;

    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            if (msg.what == 0x001) {
                adapter.add((String) msg.obj);
            } else if (msg.what == 0x002) {
                Toast.makeText(MainActivity.this,
                        "connect fail", Toast.LENGTH_SHORT)
                        .show();
            }
        }
    };

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

        USERNAME = ((EditText) findViewById(R.id.etUserName)).getText()
                .toString();
        USERNAME += "@***.com";//这里是你的域名。一般公司给员工分配的用户名都有@的后缀
        PASSWORD = ((EditText) findViewById(R.id.etPwd)).getText().toString();
        Log.i("USERNAME", USERNAME);
        Log.i("PASSWORD", PASSWORD);

        listView = (ListView) findViewById(R.id.listView1);
        adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1);
        listView.setAdapter(adapter);
        ((Button) findViewById(R.id.btnGet))
                .setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        adapter.clear();
                        new Thread(new Runnable() {
                            @Override
                            public void run() {
                                client = new FTPClient();
                                try {
                                    client.connect(HOST, PORT);
                                    client.login(USERNAME, PASSWORD);
                                    String[] file = client.listNames();
                                    for (int i = 0; i < file.length; i++) {
                                        Log.i("file", file[i]);
                                        Message message = handler
                                                .obtainMessage(0x001, file[i]);
                                        handler.sendMessage(message);
                                    }
                                } catch (Exception e) {
                                    handler.sendEmptyMessage(0x002);
                                    return;
                                }
                            }
                        }).start();
                    }
                });
        /**
         * commons-net-3.0.1.jar 
         * listNames返回NULL,list返回Int,listFiles返回NULL
         * 因为传进去的参数是(String)null
         * 自己可以去了解，我这里就不演示了
         */

        listView.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    final int position, long id) {
                String dir = Environment.getExternalStorageDirectory()
                        + "/test/";
                File fileDir = new File(dir);
                if (!fileDir.exists()) {
                    fileDir.mkdirs();
                }
                String path = dir + adapter.getItem(position);
                final File file = new File(path);
                if (file.exists()) {
                    file.delete();
                    Log.i("delete", "original file deleted");
                }
                try {
                    new Thread(new Runnable() {
                        @Override
                        public void run() {
                            try {
                                // 参考/doc/manual.en.html，最后面的参数是监听器
                                client.download(adapter.getItem(position),
                                        file, new MyTransferListener());
                            } catch (Exception e) {
                                e.printStackTrace();
                            }
                        }
                    }).start();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public class MyTransferListener implements FTPDataTransferListener {
        public void started() {
            Log.i("download", "download start");
        }

        public void transferred(int length) {
            Log.i("download", "have download " + length + " bytes");
        }

        public void completed() {
            Log.i("download", "download completed");
        }

        public void aborted() {
            Log.i("download", "download aborted");
        }

        public void failed() {
            Log.i("download", "download failed");
        }
    }
}

<uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />