Reading and writing txt files stored in device are very easy and doesn't need too much work.
--------------------------This will go in the file_handling_activity.xml file.-----------------------------
-----------------------------The FileHandlingActivity.java code---------------------------
Please note: You need to provide the Write Permission in the device.
--------------------------This will go in the file_handling_activity.xml file.-----------------------------
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"----------------------------------------------------------------------
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#339949"
android:orientation="vertical"
android:weightSum="10">
<EditText
android:id="@+id/fha_dataET"
android:layout_width="match_parent"
android:layout_height="0dp"
android:singleLine="false"
android:hint="Type here"
android:textColor="#ffffff"
android:textSize="25sp"
android:layout_weight="9"/>
<Button
android:id="@+id/fha_closeBTN"
android:background="#005f00"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_gravity="center"
android:text="Close"
android:textSize="25sp"
android:textColor="#ffffff"
android:layout_weight="1"/>
</LinearLayout>
-----------------------------The FileHandlingActivity.java code---------------------------
package com.app.yourappname;-----------------------------------------------------------------------------
import android.os.Bundle;
import android.os.Environment;
import android.util.Base64;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
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.PrintWriter;
import androidx.appcompat.app.AppCompatActivity;
public class FileHandlingActivity extends AppCompatActivity {
private EditText myData;
private String myFilePath = "MyFilePath";
private File myNewDir = new File(Environment.getExternalStorageDirectory(), "MyNewDir");
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.file_handling_activity);
myData = findViewById(R.id.fha_dataET);
Button btn = findViewById(R.id.fha_closeBTN);
btn.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) { finish(); }
});
}
@Override
protected void onResume() {
if(!myNewDir.exists())
myNewDir.mkdir();
File file = new File(myNewDir, myFilePath);
try {
FileReader inputFile = new FileReader(file);
BufferedReader bufferReader = new BufferedReader(inputFile);
String line, wholeText="";
while ((line = bufferReader.readLine()) != null) {
wholeText = wholeText + line;
}
byte[] decodedBytes = Base64.decode(wholeText, Base64.DEFAULT);
String decodeByteArray = new String(decodedBytes);
myData.setText(decodeByteArray);
bufferReader.close();
}catch(Exception e){
System.out.println("Could not read file line by line:"+ e.getMessage());
}
super.onResume();
}
@Override
protected void onPause() {
byte[] encodedBytes = Base64.encode(myData.getText().toString().getBytes(), Base64.DEFAULT);
String encodeByteArray = new String(encodedBytes);
File file = new File(myNewDir, myFilePath);
if(!file.exists())
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
try {
FileOutputStream f = new FileOutputStream(file);
PrintWriter pw = new PrintWriter(f);
pw.println(encodeByteArray);
pw.flush();
pw.close();
f.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
Log.i("Please check", "WRITE_EXTERNAL_STORAGE permission manifest is missing.");
} catch (IOException e) {
e.printStackTrace();
}
super.onPause();
}
}
------- Add write external storage permission and Declare Activity name in Manifest ---------------
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.app.yourappname">
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<supports-screens
android:smallScreens="true"
android:normalScreens="true"
android:largeScreens="true"
android:xlargeScreens="true"
android:anyDensity="true" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".FileHandlingActivity" android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
-----------------------------------------------------------------------------
