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();
}
}
}