package org.lxh.demo;import java.io.File; import java.io.FileOutputStream;import java.io.PrintStream;  import android.app.Activity;import android.os.Bundle;public class FileOperate extends Activity {    // 设置文件名称    private static final String FILENAME =                   "/mnt/sdcard/mldndata/mymldn.txt" ;        @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        super.setContentView(R.layout.main);        // 定义要操作的文件        File file = new File(FILENAME) ;             // 文件不存在        if(!file.getParentFile().exists()) {            // 创建文件夹路径            file.getParentFile().mkdirs() ;            }        // 打印流对象用于输出        PrintStream out = null;        try {            out = new PrintStream(new FileOutputStream(file));            out.println("噜啦啦啦啦啦啦啦");        } catch (Exception e) {            e.printStackTrace() ;        } finally {    // 一定要关闭流            if(out != null) {                out.close() ;            }        }    }}
     
     

从sdcard读取文件

File file2 = new File(FILENAME);        if (!file2.getParentFile().exists()) {            file2.getParentFile().mkdirs();        }        Scanner scann = null;        try {            scann = new Scanner(new FileInputStream(file2));            while (scann.hasNext()) {                this.tv_msg.append(scann.next() + "\n");                            }        } catch (Exception e) {            // TODO: handle exception        } finally {            if (scann != null) {                scann.close();            }        }