关于Android文件的读写有两种方式
一种是将txt文件当成资源文件放在res/raw或则res/asset文件夹下，raw的文件可以通过R.raw.fileName获得，asset下的文件可以通过AssetManager am = getAssets();am.open(“FileName”);来打开文件。但是如果把文件当成资源文件存放的话，只能读不能写。如果要想写入数据的话，就使用第二种方法
第二种方法从sd卡中读写文件，这样首先要向AndroidManifest.xml中加入两条权限消息
然后将文件操作封装在一个类中，在这里我把它命名为FileOption，先将代码粘贴如下：
package com.example.littleapplication;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.util.Vector;
import android.os.Environment;
import android.util.Log;
public class FileOption {
private String fileName;
private File targetFile;
private File sdCardDir;
public FileOption(String fileName) throws IOException {
// TODO Auto-generated constructor stub
boolean mark = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);
if(mark)
{
this.fileName = fileName;
this.sdCardDir = Environment.getExternalStorageDirectory();
this.targetFile = new File(this.sdCardDir.getCanonicalPath()+this.fileName);
if(this.targetFile.exists()==false)
{
this.targetFile.createNewFile();
}
}
else{
Log.e("SDK", "无内存卡");
}
}
public Vector read() throws FileNotFoundException, IOException {
FileInputStream fis = new FileInputStream(this.sdCardDir.getCanonicalPath()+this.fileName);
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
Vector res = new Vector();
String line = null;
while((line = br.readLine())!=null)
{
res.add(line);
}
br.close();
return res;
// TODO Auto-generated method stub
}
public boolean write(String add) throws IOException
{
RandomAccessFile raf = new RandomAccessFile(this.targetFile,"rw");
raf.seek(targetFile.length());
//换行
raf.write(add.getBytes());
raf.writeChar('\n');
raf.close();
return true;
}
/**返回一共有多少条记录
* @throws IOException
* @throws FileNotFoundException */
public int size() throws FileNotFoundException, IOException
{
FileInputStream fis = new FileInputStream(this.sdCardDir.getCanonicalPath()+this.fileName);
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
String line = null;
int count = 0;
while((line = br.readLine())!=null)
{
count++;
}
//每三行代表一个数据项
//分别是 id title content data level
return count/5;
}
}