How to Read and Write from a File in Android Studio

 How to Read and Write from a File in Android Studio

In this Tutorial How to Read and Write from a File in Android studio follow this tutorial How to Read and Write from a File in Android studio

1.MainActivity.java:

import java.io.BufferedReader;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.FileReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

 

import android.app.Activity;

import android.content.Context;

import android.os.Bundle;

import android.os.Environment;

import android.util.Log;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import android.widget.Toast;

 

public class MainActivity extends Activity {

 

    private static final String TAG = MainActivity.class.getName();

    private static final String FILENAME = "myFile.txt";

 

    TextView text;

 

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

 

        text = (TextView) findViewById(R.id.textView1);

 

        Button Read = (Button) findViewById(R.id.read);

        Button write = (Button) findViewById(R.id.writefile);

 

        Read.setOnClickListener(new View.OnClickListener() {

 

            @Override

            public void onClick(View v) {

                // TODO Auto-generated method stub

                readFromFile();

                Toast.makeText(getApplicationContext(),

                        "Successfully read From file", Toast.LENGTH_SHORT)

                        .show();

            }

        });

        final String textToSaveString = "Hello Android";

 

        write.setOnClickListener(new View.OnClickListener() {

 

            @Override

            public void onClick(View v) {

                // TODO Auto-generated method stub

                writeToFile(textToSaveString);

                Toast.makeText(getApplicationContext(), "Write made to file",

                        Toast.LENGTH_SHORT).show();

 

            }

        });

 

    }

 

    private void writeToFile(String data) {

        try {

 

            FileOutputStream fos = openFileOutput(FILENAME,

                    Context.MODE_PRIVATE);

            fos.write(data.getBytes());

            fos.close();

 

        } catch (IOException e) {

            Log.e(TAG, "File write failed: " + e.toString());

        }

 

    }

 

    private void readFromFile() {

        File file = new File(this.getFilesDir() + "/", FILENAME);

        if (!file.exists()) {

            throw new RuntimeException("File not found");

        }

        Log.e("Testing", "Starting to read");

        BufferedReader reader = null;

        StringBuilder builder = null;

        try {

            reader = new BufferedReader(new FileReader(file));

            builder = new StringBuilder();

            String line;

            while ((line = reader.readLine()) != null) {

                builder.append(line);

            }

        } catch (Exception e) {

            e.printStackTrace();

        } finally {

            if (reader != null) {

                try {

                    reader.close();

                } catch (IOException e) {

                    e.printStackTrace();

                }

            }

        }

        text.setText(builder.toString());

    }

 

}

2.Activity_main.xml:

<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" >

 

    <Button

        android:id="@+id/writefile"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_alignParentRight="true"

        android:layout_alignParentTop="true"

        android:layout_marginTop="35dp"

        android:text="Write" />

 

    <Button

        android:id="@+id/read"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/writefile"

        android:layout_alignParentRight="true"

        android:layout_centerVertical="true"

        android:text="Read" />

 

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/read"

        android:layout_alignParentBottom="true"

        android:layout_alignParentRight="true"

        android:layout_below="@+id/read"

        android:layout_marginTop="58dp"

        android:text="Output Text"

        android:textAppearance="?android:attr/textAppearanceLarge" />

 

</RelativeLayout>