从sdcard读取文件

 

 

 

在main.xml中：

 

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout

    xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical" >

 

    <TextView

        android:id="@+id/msg"

        android:layout_margin="8dp"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"/>

 

</LinearLayout>

 

 

 

 

 

在MyFileOperateDemo.java程序中

 

package com.li.fileoperate;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.PrintStream;

import java.util.Scanner;

 

import android.app.Activity;

import android.os.Bundle;

import android.os.Environment;

import android.widget.TextView;

import android.widget.Toast;

 

public class MyFileOperateDemo extends Activity {

  private static final String FILENAME = "/mnt/sdcard/liyewen.txt";  // 设置文件名称

  private static final String DIR = "File"; //操作文件夹的名称

  private TextView msg = null;

  @Override

  public void onCreate(Bundle savedInstanceState) {

     super.onCreate(savedInstanceState);

     super.setContentView(R.layout.main);

     this.msg = (TextView)super.findViewById(R.id.msg);

    

    if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){

       File file = new File(Environment.getExternalStorageDirectory()

            + File.separator + DIR + File.separator + FILENAME) ;   // 定义要操作的文件

       if(!file.getParentFile().exists()) {

         file.getParentFile().mkdirs() ;  // 创建父文件夹路径

       }

       Scanner scan = null;

       try {

         scan = new Scanner(new FileInputStream(file));

         while(scan.hasNext()){

            this.msg.append(scan.next() + "\n");

         }

       } catch (Exception e) {

         e.printStackTrace() ;

       } finally { // 一定要关闭流

         if(scan != null) {

            scan.close() ;

         }

       }

     }else{

       Toast.makeText(this, "SD卡不存在，保存失败！", Toast.LENGTH_LONG).show();

     }

  }

}