How to make a txt file in external storage with runtime permission in android?

This example demonstrates How to make a txt file in external storage with runtime permission in android.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version = "1.0" encoding = "utf-8"?>
<LinearLayout 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"
   android:orientation = "vertical">
   <EditText
      android:id = "@+id/enterText"
      android:hint = "Please enter text here"
      android:layout_width = "match_parent"
      android:layout_height = "wrap_content" />
   <Button
      android:id = "@+id/save"
      android:text = "Save"
      android:layout_width = "wrap_content"
      android:layout_height = "wrap_content" />
</LinearLayout>

In the above code, we have taken edit text and button. When user click on button, it will take data from edit text and store in external storage.

Step 3 − Add the following code to src/MainActivity.java

package com.example.andy.myapplication;

import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {
   private static final int PERMISSION_REQUEST_CODE = 100;
   Button save;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);

      final EditText enterText = findViewById(R.id.enterText);
      save = findViewById(R.id.save);
      save.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            if (!enterText.getText().toString().isEmpty()) {
               String state = Environment.getExternalStorageState();
               if (Environment.MEDIA_MOUNTED.equals(state)) {
                  if (Build.VERSION.SDK_INT > = 23) {
                     if (checkPermission()) {
                        File sdcard = Environment.getExternalStorageDirectory();
                        File dir = new File(sdcard.getAbsolutePath() + "/text/");
                        dir.mkdir();
                        File file = new File(dir, "sample.txt");
                        FileOutputStream os = null;
                        try {
                           os = new FileOutputStream(file);
                           os.write(enterText.getText().toString().getBytes());
                           os.close();
                        } catch (IOException e) {
                           e.printStackTrace();
                        }
                     } else {
                        requestPermission(); // Code for permission
                     }
                  } else {
                     File sdcard = Environment.getExternalStorageDirectory();
                     File dir = new File(sdcard.getAbsolutePath() + "/text/");
                     dir.mkdir();
                     File file = new File(dir, "sample.txt");
                     FileOutputStream os = null;
                     try {
                        os = new FileOutputStream(file);
                        os.write(enterText.getText().toString().getBytes());
                        os.close();
                     } catch (IOException e) {
                        e.printStackTrace();
                     }
                  }
               }
            }
         }
      });
   }
   private boolean checkPermission() {
      int result = ContextCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
      if (result = = PackageManager.PERMISSION_GRANTED) {
         return true;
      } else {
         return false;
      }
   }

   private void requestPermission() {
      if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
      Toast.makeText(MainActivity.this, "Write External Storage permission allows us to create files. Please allow this permission in App Settings.", Toast.LENGTH_LONG).show();
      } else {
         ActivityCompat.requestPermissions(MainActivity.this, new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_REQUEST_CODE);
      }
   }

   @Override
   public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
      switch (requestCode) {
         case PERMISSION_REQUEST_CODE:
         if (grantResults.length > 0 && grantResults[0] = = PackageManager.PERMISSION_GRANTED) {
            Log.e("value", "Permission Granted, Now you can use local drive .");
         } else {
            Log.e("value", "Permission Denied, You cannot use local drive .");
         }
         break;
      }
   }
}

Step 4 − Add the following code to manifest.xml

<?xml version = "1.0" encoding = "utf-8"?>
<manifest xmlns:android = "http://schemas.android.com/apk/res/android"
   package = "com.example.andy.myapplication">
   <uses-permission android:name = "android.permission.WRITE_EXTERNAL_STORAGE"/>
   <uses-permission android:name = "android.permission.READ_EXTERNAL_STORAGE"/>
   <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 = ".MainActivity">
         <intent-filter>
            <action android:name = "android.intent.action.MAIN" />
            <category android:name = "android.intent.category.LAUNCHER" />
         </intent-filter>
     </activity>
  </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −

In the above result, we have added some text and clicked on save button as shown below –

At first time, it will ask runtime permission to access external storage. To verify the above result, open your external storage and check for text folder as shown below -

Click here to download the project code