Android实现SD卡和实现内存文件存储的做法基本是一样的。只是取得文件路径的方法不一样，基本上跟java的文件操作是一致的，下面是程序的代码。配置取的位置和实现有所不同，其他是一样的，下面是代码：

main.xml:

<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:orientation="vertical"  android:layout_width="fill_parent"  android:layout_height="fill_parent">  
<EditText android:id="@+id/edit1"  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:lines="4"/>  
<Button android:id="@+id/write"  android:layout_width="wrap_content"  android:layout_height="wrap_content"   android:text="@string/write"/>  
<EditText android:id="@+id/edit2"  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:editable="false"  android:cursorVisible="false"  android:lines="4"/>        
<Button android:id="@+id/read"  android:layout_width="wrap_content"  android:layout_height="wrap_content"   android:text="@string/read"/>  
</LinearLayout>  

在AndroidManifest清单文件中要对SD卡读取进行支持。代码如下：

<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>  
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> 

在String.xml中添加两个内容:

<string name="read">读取</string>  
lt;string name="write">写入</string>   

下面是文件实现的代码：

package cn.jason.io;import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;public class FileTestActivity extends Activity {final String FILE = "jason.bin";@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);Button read = (Button) findViewById(R.id.read);Button write = (Button) findViewById(R.id.write);final EditText edit1 = (EditText) findViewById(R.id.edit1);final EditText edit2 = (EditText) findViewById(R.id.edit2);write.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {write(edit1.getText().toString());edit1.setText("");}});read.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {edit2.setText(read());}});}private String read() {try {FileInputStream fis = openFileInput(FILE);byte[] buffer = new byte[1024];int hasRead = 0;StringBuilder sb = new StringBuilder("");while ((hasRead = fis.read(buffer)) > 0) {sb.append(new String(buffer, 0, hasRead));}return sb.toString();} catch (IOException e) {e.printStackTrace();}return null;}private void write(String content){try{// 以追加模式打开文件输出流FileOutputStream fos = openFileOutput(FILE, MODE_APPEND);// 将FileOutputStream包装成PrintStreamPrintStream ps = new PrintStream(fos);// 输出文件内容ps.println(content);ps.close();}catch (Exception e){e.printStackTrace();}}
}

下面是sd卡存储实现的代码：

package cn.jason.io;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.net.ContentHandler;import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;public class SDCardTestActivity extends Activity {final String FILE = "/jason.bin";@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);Button read = (Button) findViewById(R.id.read);Button write = (Button) findViewById(R.id.write);// 获取两个文本框final EditText edit1 = (EditText) findViewById(R.id.edit1);final EditText edit2 = (EditText) findViewById(R.id.edit2);// 为write按钮绑定事件监听器write.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View source) {// 将edit1中的内容写入文件中write(edit1.getText().toString());edit1.setText("");}});read.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// 读取指定文件中的内容，并显示出来edit2.setText(read());}});}private String read() {// 如果手机插入了SD卡，而且应用程序具有访问SD的权限try {if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {// 获取SD卡的目录File sdDirFile = Environment.getExternalStorageDirectory();//获取指定文件对应的输入流FileInputStream fis = new FileInputStream(sdDirFile.getCanonicalPath()+ FILE);//将指定输入流包装成BufferedReaderBufferedReader br = new BufferedReader(new InputStreamReader(fis));StringBuilder sb = new StringBuilder("");String line = null;while ((line =br.readLine())!=null) {sb.append(line);}return sb.toString();}} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return null;}private void write(String context){try {if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){File sdDir = Environment.getExternalStorageDirectory();File targetFile = new File(sdDir.getCanonicalPath()+ FILE);RandomAccessFile raf = new RandomAccessFile(targetFile, "rw");raf.seek(targetFile.length());raf.write(context.getBytes());raf.close();}} catch (Exception e) {}}
}

转自：http://www.open-open.com/lib/view/open1338474717183.html