gistfile1.java

package com.example.andfileapp2;


import java.io.BufferedWriter;
import java.io.FileWriter;

import java.io.BufferedReader;
import java.io.FileReader;


import android.os.Environment;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;



public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        String arg2 ="";
        
        // Write
        {
            try {  
                String sdPath = Environment.getExternalStorageDirectory().getPath();  
                
                
                arg2=arg2+"\n"+sdPath;
                
                String fileName = "/Hello.txt";  
                BufferedWriter bw = null;  
                try {  
                    FileWriter fw = new FileWriter(sdPath + fileName);  
                    bw = new BufferedWriter(fw);  
                    bw.write("hello");  
                } finally {  
                    bw.close();  
                }  
            } catch (Exception e) {  
                e.printStackTrace();  
           
              arg2=arg2+e.toString();	
            }  
        }
        
        String readString="";
        // Read
        {
            try {  
                String sdPath = Environment.getExternalStorageDirectory().getPath();  
                String fileName = "/Hello.txt";  
                BufferedReader br = null;  
                try {  
                    FileReader fr = new FileReader(sdPath + fileName);  
                    br = new BufferedReader(fr);  
                    StringBuilder sb = new StringBuilder();     
                    String str;     
                    while((str = br.readLine()) != null){     
                        sb.append(str +"\r\n");     
                    }  
             //       Toast.makeText(this, sb.toString(), Toast.LENGTH_LONG).show();  
                    readString = sb.toString();
                
                
                } finally {  
                    br.close();  
                }  
            }catch (Exception e){  
                e.printStackTrace();  
            	arg2=arg2+e.toString();	
            }  
        }
        
        TextView tv = new TextView(this);
        tv.setText("Hello, Android"+arg2+"\n"+readString);
        setContentView(tv);
        
    }
}

gistfile2.txt

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="@string/hello_world" />

</RelativeLayout>

gistfile3.txt

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.andfileapp2"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.andfileapp2.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
        <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
    

</manifest>