SD卡文件浏览器案例

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context="com.example.sdcard_browser.MainActivity"
    android:orientation="vertical">

    <TextView
        android:id="@+id/current_path"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"/>
    <ListView
        android:id="@+id/file_browser"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/current_path"/>
    <Button
        android:id="@+id/back"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/back"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"/>
</RelativeLayout>

Activity代码：

public class MainActivity extends AppCompatActivity {
    //  定义父文件
    private File currentParent;
    //  存放当前父文件中的所有子文件
    private File currentFiles[];
    //   用于显示当前父文件的路径
    private TextView textView;
    //   返回上一层按钮
    private Button back;
    //   定义ListView用于加载文件列表
    private ListView fileListView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        fileListView = (ListView) findViewById(R.id.file_browser);
        back = (Button) (Button) findViewById(R.id.back);
        textView = (TextView) findViewById(R.id.current_path);
        //   获取SD卡目录文件
        File root = new File("/mnt/sdcard");
        if(root.exists()){
            currentParent = root;
            //  listFiles()方法可得到当前文件下的所有文件
            currentFiles = currentParent.listFiles();

            filesInflateView(currentFiles);
        }
        fileListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if(currentFiles[position].isFile()) return;
                File temp[] = currentFiles[position].listFiles();
                if(temp == null || temp.length == 0){
                    Toast.makeText(MainActivity.this, "该文件夹为空或不可访问",
                            Toast.LENGTH_SHORT).show();
                }else{
                    currentParent = currentFiles[position];
                    currentFiles = temp;
                    filesInflateView(currentFiles);
                }
            }
        });
        back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    //  若当前的父文件的目录不是SD卡目录
                    if(!currentParent.getCanonicalPath().equals("/storage/emulated/legacy")){
                        currentParent = currentParent.getParentFile();
                        currentFiles = currentParent.listFiles();
                        filesInflateView(currentFiles);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });

    }

    private void filesInflateView(File currenFiles[]){
        List<Map<String,Object>> listItems = new ArrayList<Map<String, Object>>();
        for (int i = 0; i < currenFiles.length;i++){
            HashMap<String,Object> map = new HashMap<String,Object>();
            if(currentFiles[i].isDirectory()){
                map.put("icon",R.drawable.file);
            }else{
                map.put("icon",R.drawable.sun_file);
            }
            map.put("fileName",currenFiles[i].getName());
            listItems.add(map);
        }
        SimpleAdapter adapter = new SimpleAdapter(this,listItems,R.layout.file_item,
                new String[]{"icon","fileName"},new int[]{R.id.fileImage,R.id.fileName});
        fileListView.setAdapter(adapter);
        try {
            textView.setText("当前路径:"+currentParent.getCanonicalPath());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

注：文件夹图片在windows上截的，哈哈~~~