Android File Handling

Lets learn File handling in Android.

First, create a layout to enter and save the data and to display the saved data.

<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"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >

    <EditText 

        android:id="@+id/et"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:hint="Enter Here"

        />

    

    <TextView

        android:id="@+id/tv"

        android:layout_below="@+id/et"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        />

    <Button

        android:id="@+id/read"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/save"

        android:layout_alignBottom="@+id/save"

        android:layout_toRightOf="@+id/save"

        android:text="READ" />

    <Button

        android:id="@+id/save"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/tv"

        android:layout_centerVertical="true"

        android:text="SAVE" />

</RelativeLayout>

And then make changes in the MainActivity.java.

package com.codingredefined.androidfilehandling;

import java.io.FileInputStream;
import java.io.FileOutputStream;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity
{
Button b1,b2;
EditText et;
TextView tv;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1=(Button)findViewById(R.id.save);
b2=(Button)findViewById(R.id.read);
et=(EditText)findViewById(R.id.et);
tv=(TextView)findViewById(R.id.tv);
b1.setOnClickListener(new View.OnClickListener()
{

@Override
public void onClick(View v)
{
// TODO Auto-generated method stub
String str=et.getText().toString();
FileOutputStream fos;
try
{
fos=openFileOutput("abc",Context.MODE_PRIVATE);
fos.write(str.getBytes());
fos.close();
Toast.makeText(MainActivity.this,"Data Saved",Toast.LENGTH_SHORT).show();
}
catch(Exception e)
{
Toast.makeText(MainActivity.this,"Data NOT Saved",Toast.LENGTH_SHORT).show();
}
}
});
b2.setOnClickListener(new View.OnClickListener()
{

@Override
public void onClick(View v)
{
// TODO Auto-generated method stub
FileInputStream fis;
try
{
fis=openFileInput("abc");
int i=0;
String str="";
while((i=fis.read())!=-1)
{
str=str+((char)+i);
}
tv.setText(str);
fis.close();
}
catch(Exception e)
{
Toast.makeText(MainActivity.this,"Data NOT Read",Toast.LENGTH_SHORT).show();
}
}
});
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}

The following output is obtained.