列举文件夹中所有文件

package com.edison.ex;

import java.io.File;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;

public class ListAllFiles {

	public Context mCon;
	public List<File> fileNameList;
	/***/
	public ArrayList<String> fnList;

	public ListAllFiles(Context mCon) {
		this.mCon = mCon;
	}

	public void initFileList(String mPath) {
		File path = new File(mPath);
		File[] f = path.listFiles();
		fill(f);
	}

	/** Returns an array of files contained in the directory */
	public void initFileList(File mFile) {
		File[] f = mFile.listFiles();
		fill(f);
	}

	public void fill(File[] files) {
		fileNameList = new ArrayList<File>();
		for (File file : files) {
			if (isValidFileOrDir(file)) {
				fileNameList.add(file);
			}
		}
		System.out.println("fileNameList.size===" + fileNameList.size());
		fileToStrArr(fileNameList);
	}

	/** 将文件夹或文件名字的名称保存到字符串数组当中. */
	private String[] fileToStrArr(List<File> fl) {
		fnList = new ArrayList<String>();
		for (int i = 0; i < fl.size(); i++) {
			String nameString = fl.get(i).getName();
			fnList.add(nameString);
		}
		System.out.println("fnList.size===" + fnList.size());
		return fnList.toArray(new String[0]);
	}

	/** 检查是否为合法的文件夹名和文件（文件是否为txt文件） */
	private boolean isValidFileOrDir(File file) {
		if (file.isDirectory()) {
			return true;
		} else {
			String fileName = file.getName().toLowerCase();
			if (fileName.endsWith(".txt")) {
				return true;
			}
		}
		return false;
	}
}

package com.edison.ex;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.TextView;

public class ViewFile extends Activity {

	private String filenameString;
	private static final String gb2312 = "GB2312";
	private static final String utf8 = "UTF-8";
	private static final String defaultCode = gb2312;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.filebrowser);
		try {
			Bundle bunde = this.getIntent().getExtras();
			filenameString = bunde.getString("fileName");
			refreshGUI(defaultCode);
		} catch (Exception e) {
		}
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		MenuInflater inflater = this.getMenuInflater();
		inflater.inflate(R.menu.menu, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		switch (item.getItemId()) {
		case R.id.gb2312:
			refreshGUI(defaultCode);
			break;
		case R.id.utf8:
			refreshGUI(utf8);
			break;
		}
		return super.onOptionsItemSelected(item);
	}

	private void refreshGUI(String code) {
		TextView tv = (TextView) findViewById(R.id.view_contents);
		String fileContent = getStringFromFile(code);
		tv.setText(fileContent);
	}

	public String getStringFromFile(String code) {
		try {
			StringBuffer sBuffer = new StringBuffer();
			FileInputStream fInputStream = new FileInputStream(filenameString);
			InputStreamReader inputStreamReader = new InputStreamReader(
					fInputStream, code);
			BufferedReader in = new BufferedReader(inputStreamReader);
			if (!new File(filenameString).exists()) {
				return null;
			}
			while (in.ready()) {
				sBuffer.append(in.readLine() + "\n");
			}
			in.close();
			return sBuffer.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	// 读取文件内容
	public byte[] readFile(String fileName) throws Exception {
		byte[] result = null;
		FileInputStream fis = null;
		try {
			File file = new File(fileName);
			fis = new FileInputStream(file);
			result = new byte[fis.available()];
			fis.read(result);
		} catch (Exception e) {
		} finally {
			fis.close();
		}
		return result;
	}

}

package com.edison.ex;

import java.io.File;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class ReadTextActivity extends ListActivity {

	ListAllFiles mListAllFiles;
	ArrayAdapter<String> adapter;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		mListAllFiles = new ListAllFiles(this);
		mListAllFiles.initFileList(android.os.Environment
				.getExternalStorageDirectory());
		adapter = new ArrayAdapter<String>(this,
				android.R.layout.simple_list_item_1, mListAllFiles.fnList);
		setListAdapter(adapter);
	}

	@Override
	protected void onListItemClick(ListView l, View v, int position, long id) {
		Intent intent = new Intent(ReadTextActivity.this, ViewFile.class);
		Bundle bundle = new Bundle();
		File file = mListAllFiles.fileNameList.get(position);
		if (file.isDirectory()) {
			File[] f = file.listFiles();
			mListAllFiles.fill(f);
			adapter = new ArrayAdapter<String>(this,
					android.R.layout.simple_list_item_1, mListAllFiles.fnList);
			setListAdapter(adapter);
		} else {
			bundle.putString("fileName", file.getAbsolutePath());
			intent.putExtras(bundle);
			startActivityForResult(intent, 0);
		}
	}
}