<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="wrap_content"
  android:orientation="vertical"
  android:layout_gravity="center_horizontal"
  tools:context=".MainActivity" >
  <TextView
    android:id="@+id/txt1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
  <ImageButton
    android:id="@+id/imageBt1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/home"/>
  <ListView
    android:id="@+id/listFile"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" >
  </ListView>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="horizontal" >
  <ImageView
    android:id="@+id/images"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
  <TextView
    android:id="@+id/txtview"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
</LinearLayout>

package com.android.xiong.sdfilelook;
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
public class MainActivity extends Activity {
  private ListView listfile;
  //當前文件目錄
  private String currentpath;
  private TextView txt1;
  private ImageView images;
  private TextView textview;
  private ImageButton imagebt1;
  private int[] img = { R.drawable.file, R.drawable.folder, R.drawable.home };
  private File[] files;
  private SimpleAdapter simple;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    listfile = (ListView) findViewById(R.id.listFile);
    txt1 = (TextView) findViewById(R.id.txt1);
    imagebt1 = (ImageButton) findViewById(R.id.imageBt1);
    init(Environment.getExternalStorageDirectory());
    listfile.setOnItemClickListener(new OnItemClickListener() {
      @Override
      public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
          long arg3) {
        // TODO Auto-generated method stub
        // 獲取單擊的文件或文件夾的名稱
        String folder = ((TextView) arg1.findViewById(R.id.txtview))
            .getText().toString();
        try {
          File filef = new File(currentpath + '/'
              + folder);
          init(filef);
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
    });
    //回根目錄
    imagebt1.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
        init(Environment.getExternalStorageDirectory());
      }
    });
  }
  // 界面初始化
  public void init(File f) {
    if (Environment.getExternalStorageState().equals(
        Environment.MEDIA_MOUNTED)) {
      // 獲取SDcard目錄下所有文件名
      files = f.listFiles();
      if (!files.equals(null)) {
        currentpath=f.getPath();
        txt1.setText("當前目錄為:"+f.getPath());
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
        for (int i = 0; i < files.length; i++) {
          Map<String, Object> maps = new HashMap<String, Object>();
          if (files[i].isFile())
            maps.put("image", img[0]);
          else
            maps.put("image", img[1]);
          maps.put("filenames", files[i].getName());
          list.add(maps);
        }
        simple = new SimpleAdapter(this, list,
            R.layout.fileimageandtext, new String[] { "image",
                "filenames" }, new int[] { R.id.images,
                R.id.txtview });
        listfile.setAdapter(simple);
      }
    } else {
      System.out.println("該文件為空");
    }
  }
  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
  }
}

<!-- 在SDCard中創建與刪除文件權限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<!-- 往SDCard寫入數據權限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />