一、主要思路

主要是通过ListView实现。

考虑到以后会添加长按修改功能，所以好几个地方都是用的FramLayout，而且CheckBox初始状态是被隐藏的。给ListView添加OnItemClickedListener，在识别点击的Item是文件夹时做出响应，把ListView的资源来源改成该文件夹。同时顶部的TextView也要修改成对应文件夹目录。

目前我没有对返回键设置监听器，所以返回上一级菜单是通过顶部的按钮实现的。在根目录下该按钮隐藏，等到进入下一级目录的时候按钮就会显示出来。

二、FileBean

FileBean是文件/文件夹的抽象类，包含文件所需的一些必要属性。

package com.example.vcloud_3_25.bean;

import java.util.Date;

/*
* 包含文件的通用属性和方法
*/
public class FileBean {
public static final int ROOT = 0x7fffffff;
private int id;
private int pId;
private String name;
private String type;
private String info;
private Date date;

public int getId() {  
    return id;  
}

public void setId(int id) {  
    this.id = id;  
}

public int getpId() {  
    return pId;  
}

public void setpId(int pId) {  
    this.pId = pId;  
}

public String getName() {  
    return name;  
}

public void setName(String name) {  
    this.name = name;  
}

public String getType() {  
    return type;  
}

public void setType(String type) {  
    this.type = type;  
}

public String getInfo() {  
    return info;  
}

public void setInfo(String info) {  
    this.info = info;  
}

public Date getDate() {  
    return date;  
}

public void setDate(Date date) {  
    this.date = date;  
}

public FileBean(int id, int pId, String name, String type, Date date) {  
    super();  
    this.id = id;  
    this.pId = pId;  
    this.name = name;  
    this.type = type;  
    this.date = date;  
}

}

三、FileHelper

我是这样考虑的，要把一个目录下的所有文件加载出来，就需要设置pId-->FileBeanList的对应关系，所以最方便的就是通过Map实现。在编写过程中程序提示我可以使用SparseArray来代替HashMap，可以提升效率，所以我就使用SparseArray来实现了。至于初始数据如何得到我还没有考虑，所以就在构造函数里自定义了一些数据，这些FileBean是没有预先排好序列，也不具备我预想的pId-->FileBeanList结构，所以我在FileHelper这个类中编写了基础的排序以及结构化的函数。

package com.example.vcloud_3_25.utils;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
import android.util.SparseArray;

import com.example.vcloud_3_25.bean.FileBean;

public class FileHelper {
private List mList;

public FileHelper(){  
    FileBean f1 = new FileBean(1, FileBean.ROOT, "folder1", "folder",  
            new Date());  
    FileBean f2 = new FileBean(2, FileBean.ROOT, "avi1", "avi", new Date());  
    FileBean f3 = new FileBean(3, FileBean.ROOT, "folder2", "folder",  
            new Date());  
    FileBean f4 = new FileBean(4, 1, "txt1", "txt", new Date());  
    FileBean f5 = new FileBean(5, 1, "txt2", "txt", new Date());  
    FileBean f6 = new FileBean(6, 1, "txt3", "txt", new Date());  
    FileBean f7 = new FileBean(7, 1, "txt4", "txt", new Date());  
    FileBean f8 = new FileBean(8, FileBean.ROOT, "txt5", "txt", new Date());  
    FileBean f9 = new FileBean(9, FileBean.ROOT, "txt6", "txt", new Date());

    mList = new ArrayList<FileBean>();  
    mList.add(f1);  
    mList.add(f2);  
    mList.add(f3);  
    mList.add(f4);  
    mList.add(f5);  
    mList.add(f6);  
    mList.add(f7);  
    mList.add(f8);  
    mList.add(f9);  
}  
public SparseArray<List<FileBean>> getResMap() {

    Collections.sort(mList, new MyComparator());  
    SparseArray<List<FileBean>> map = new SparseArray<List<FileBean>>();

    for (FileBean f : mList) {  
        if (getChildren(f.getId()) != null)  
            map.put(f.getId(), getChildren(f.getId()));

        else  
            map.put(f.getId(), new ArrayList());  
    }

    return map;  
}

public List<FileBean> getChildren(int id) {  
    List<FileBean> list = new ArrayList<FileBean>();  
    for (FileBean f : mList) {  
        if (f.getpId() == id)  
            list.add(f);  
    }  
    Collections.sort(list, new MyComparator());  
    return list;  
}

class MyComparator implements Comparator<FileBean> {

    @Override  
    public int compare(FileBean f1, FileBean f2) {  
        if (f1.getType() == f2.getType()) {  
            return f1.getName().compareTo(f2.getName());  
        } else if (f1.getType().equals("folder")) {  
            return -1;  
        } else if (f2.getType().equals("folder")) {  
            return 1;  
        }  
        return f1.getType().compareTo(f2.getType());  
    }

}  

}

四、HomeFragment

这个就稍微臃肿了一点，我在考虑后期重构这段代码。

有一个需要注意的点，就是如何刷新ListView的问题。这在网络上能很容易的找到答案，就是先clear一下List，然后用addAll函数添加数据，最后使用Adapter的notifyDataSetChanged()方法更新数据。因为常用所以我把它抽取为了一个函数。

package com.example.vcloud_3_25;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.Fragment;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v4.widget.SwipeRefreshLayout.OnRefreshListener;
import android.util.Log;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

import com.example.vcloud_3_25.bean.FileBean;
import com.example.vcloud_3_25.utils.FileHelper;

public class HomeFragment extends Fragment {

private ListView mListView = null;  
private FileHelper mFileHelper = null;

// Map，每一个int型id对应一个FileBean列表。用于展现文件夹包含关系。  
private SparseArray<List<FileBean>> mResMap = null;  
private List<Map<String, Object>> mResList;  
private int recentPid;  
private View view;  
private SwipeRefreshLayout refresh;  
private List<Integer> mDirList;  
private List<String> mDirStrList;  
private SimpleAdapter adapter;  
private String mDirString;  
private TextView mDirTextView;  
private ImageButton mBackButton;  
private ImageButton mAddButton;

@Override  
public View onCreateView(LayoutInflater inflater, ViewGroup container,  
        Bundle savedInstanceState) {

    initView(inflater, container);  
    initData();  
    return view;  
}

private void initData() {  
    mFileHelper = new FileHelper();  
    mResMap = mFileHelper.getResMap();  
    recentPid = FileBean.ROOT;  
    mResList = getResList(recentPid);  
    mDirList = new ArrayList<Integer>();  
    mDirStrList = new ArrayList<String>();  
    mDirList.add(FileBean.ROOT);  
    mDirStrList.add("root");  
    mDirString = "root/";

    mBackButton.setVisibility(view.INVISIBLE);

    adapter = new SimpleAdapter(this.getActivity(), mResList,  
            R.layout.file\_item, new String\[\] { "fileName", "fileDate",  
                    "fileImag", "fileCheckBox" }, new int\[\] {  
                    R.id.item\_name, R.id.item\_date, R.id.file\_imag,  
                    R.id.file\_checkbox });  
    mListView.setAdapter(adapter);

    mListView.setOnItemClickListener(new OnItemClickListener() {

        @Override  
        public void onItemClick(AdapterView<?> parent, View item,  
                int position, long id) {

            ListView lv = (ListView) parent;  
            @SuppressWarnings("unchecked")  
            HashMap<String, Object> mMap = (HashMap<String, Object>) lv  
                    .getItemAtPosition(position);  
            String type = (String) mMap.get("fileType");

            // 如果点击的是文件夹，则打开该文件夹，并且修改当前目录，修改目录列表；否则不作反应。

            if (type.equals("folder")) {  
                recentPid = (Integer) mMap.get("fileId");  
                mDirList.add(recentPid);  
                mDirStrList.add((String) mMap.get("fileName"));  
                setDirString();  
                refreshListView();  
            }

            mBackButton.setVisibility(view.VISIBLE);

        }  
    });

    refresh.setOnRefreshListener(new OnRefreshListener() {  
        @Override  
        public void onRefresh() {  
            new Handler().postDelayed(new Runnable() {  
                @Override  
                public void run() {  
                    refreshListView();  
                    refresh.setRefreshing(false);  
                }  
            }, 1000);  
        }  
    });

    mBackButton.setOnClickListener(new OnClickListener() {

        @Override  
        public void onClick(View view) {  
            mDirStrList.remove(mDirStrList.size()-1);  
            mDirList.remove(mDirList.size()-1);  
            recentPid = mDirList.get(mDirList.size()-1);  
            setDirString();  
            refreshListView();

            if(mDirList.size()==1)  
                mBackButton.setVisibility(view.INVISIBLE);  
        }  
    });  
}

private void initView(LayoutInflater inflater, ViewGroup container) {  
    view = inflater.inflate(R.layout.main\_tab\_1, container, false);  
    mListView = (ListView) view.findViewById(R.id.folder\_content\_list);  
    refresh = (SwipeRefreshLayout) view  
            .findViewById(R.id.id\_refresh\_layout);  
    mDirTextView = (TextView) view.findViewById(R.id.folder\_name);  
    mBackButton = (ImageButton) view.findViewById(R.id.id\_back\_button);  
    mAddButton = (ImageButton) view.findViewById(R.id.upload\_imag);  
}

// 该List用于和ListView绑定  
@SuppressLint("SimpleDateFormat")  
private List<Map<String, Object>> getResList(int id) {  
    List<Map<String, Object>> mMaps = new ArrayList<Map<String, Object>>();  
    Map<String, Object> map;  
    for (FileBean f : mFileHelper.getChildren(id)) {

        SimpleDateFormat formatter = new SimpleDateFormat(  
                "yyyy-MM-dd HH:mm:ss");

        map = new HashMap<String, Object>();  
        map.put("fileName", f.getName());  
        map.put("fileDate", formatter.format(new Date()));  
        map.put("fileImag", getFileImag(f.getType()));  
        map.put("fileId", f.getId());  
        map.put("fileCheckBox", R.id.file\_checkbox);  
        map.put("fileType", f.getType());

        mMaps.add(map);  
        Log.d("map.put", f.getName());  
    }  
    return mMaps;  
}

// 根据String类型的文件类型找出对应的图片ID  
private int getFileImag(String type) {  
    if (type.equals("avi"))  
        return R.drawable.avi;  
    else if (type.equals("doc"))  
        return R.drawable.doc;  
    else if (type.equals("exe"))  
        return R.drawable.exe;  
    else if (type.equals("fla"))  
        return R.drawable.fla;  
    else if (type.equals("folder"))  
        return R.drawable.folder;  
    else if (type.equals("html"))  
        return R.drawable.html;  
    else if (type.equals("mp3"))  
        return R.drawable.mp3;  
    else if (type.equals("mp4"))  
        return R.drawable.mp4;  
    else if (type.equals("pdf"))  
        return R.drawable.pdf;  
    else if (type.equals("png"))  
        return R.drawable.png;  
    else if (type.equals("ppt"))  
        return R.drawable.ppt;  
    else if (type.equals("xml"))  
        return R.drawable.xml;  
    else if (type.equals("zip"))  
        return R.drawable.zip;  
    return R.drawable.other;  
}

private void setDirString(){  
    String str = "";  
    for(String s:mDirStrList){  
        str = str+s+"/";  
    }  
    mDirTextView.setText(str);  
}  
private void refreshListView(){  
    mResList.clear();  
    mResList.addAll(getResList(recentPid));  
    adapter.notifyDataSetChanged();  
}  

}