主活动的布局文件activity_main.xml

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

android:id="@+id/filedire_button1"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="选择文件" />

android:id="@+id/filedire_textView1"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:text=" " />

显示图片如下

创建适配器所需的布局文件 adapter.xml

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical" >

android:id="@+id/adapter_listView1"

android:layout_width="match_parent"

android:layout_height="wrap_content" >

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal" >

android:id="@+id/adapter_image"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="0.48"

android:src="@drawable/ic_launcher" />

android:id="@+id/adapter_filename"

android:layout_width="242dp"

android:layout_height="match_parent"

android:text="TextView" />

主活动程序 MainActivity.java

package com.example.filedirec;

import java.io.File;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import android.os.Bundle;

import android.app.Activity;

import android.app.AlertDialog;

import android.app.AlertDialog.Builder;

import android.content.DialogInterface;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.SimpleAdapter;

import android.widget.TextView;

public class MainActivity extends Activity {

private Button chooseFile;

private TextView fileDire;

private String curPath = new String("/");

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

chooseFile = (Button)findViewById(R.id.filedire_button1);

fileDire = (TextView)findViewById(R.id.filedire_textView1);

chooseFile.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View arg0) {

// TODO Auto-generated method stub

openCurDir(curPath);

}

});

}

private void openCurDir(String curPath){

File f = new File(curPath);

File[] file = f.listFiles();

final List> listItem = new ArrayList>();

if(!curPath.equals("/")){//如果不是根目录的话就在要显示的列表中加入此项

Map map1=new HashMap();

map1.put("name", "返回上一级目录");

map1.put("image", R.drawable.back02);

map1.put("path",f.getParent());

map1.put("isDire", true);

listItem.add(map1);

}

if(file != null){//必须判断 否则目录为空的时候会报错

for(int i = 0; i < file.length; i++){

Map map=new HashMap();

map.put("name", file[i].getName());

map.put("image", (file[i].isDirectory()) ? R.drawable.folder : R.drawable.doc);

map.put("path",file[i].getPath());

map.put("isDire", file[i].isDirectory());

listItem.add(map);

}

}

SimpleAdapter adapter = new SimpleAdapter(MainActivity.this,listItem,R.layout.adapter,

new String[]{"name","image"},new int[]{R.id.adapter_filename,R.id.adapter_image});

final AlertDialog.Builder b =new Builder(MainActivity.this);

b.setAdapter(adapter, new DialogInterface.OnClickListener() {

@Override

public void onClick(DialogInterface arg0, int arg1) {

// TODO Auto-generated method stub

if((Boolean) listItem.get(arg1).get("isDire")){

openCurDir((String)listItem.get(arg1).get("path"));

}else{

fileDire.setText((String)listItem.get(arg1).get("path"));

}

}

});

b.show();

}

}

对话框显示如下