How to write to files in android studio? Where are the files stored?

Question

How would I be able to create a new file which will have a different file name each time? Would it also be possible to add line breaks when writing to these files? Also, how would I be able to access this file?

package com.example.create_recipe;

import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Spinner;

import androidx.appcompat.app.AppCompatActivity;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStreamWriter;


public class MainActivity extends AppCompatActivity  {
    EditText editTxtRecipeName, editTxtEquipment, editTxtIngredients, editTxtMethod, editPersonalStory;
    Spinner spnCountries, spnHours, spnMinutes;

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

    public void createRecipe(Context context) throws FileNotFoundException {

        //TODO Create new file - should it be named after the recipe name or a unique int id?
        String recipeName = editTxtRecipeName.getText().toString();
        String country = spnCountries.getSelectedItem().toString();
        String hours = spnHours.getSelectedItem().toString(); 
        String minutes = spnMinutes.getSelectedItem().toString();
        String  equipment = editTxtEquipment.getText().toString();
        String ingredients = editTxtIngredients.getText().toString();
        String method = editTxtMethod.getText().toString();
        String personalStory = editPersonalStory.getText().toString();
        
        //TODO Write to file, adding new line breaks between recipeName, equipment and so on. 
        
    }



}

1. You can use random file name generation, or set some constant name and change only the number of this file. For instance: File1, File2, File3. To do this, you need to check for the existence of the file. 2. In order to get a file you can implement a list that will contain all the files. It is best to create a separate folder for saving files and read only it. — ACTPOHOM, Mar 29 '22 at 15:50

score 0 · Accepted Answer · answered Mar 30 '22 at 20:02

0

WHat you need is an UUID and use it like so

val uuid = UUID.randomUUID().toString()
val path = Environment.getExternalStorageDirectory().path + "/" + FILE_NAME
val file = File(path)
BufferedOutputStream(FileOutputStream(file.path)).use { stream ->
    stream.write(uuid.toByteArray())
}

Please noteEnvironment.getExternalStorageDirectory() will not work post API 29. This example is just meant to show the use of UUID to generate unique values to store

answered Mar 30 '22 at 20:02

Narendra_Nath

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This does work for generating random file names, but I don't think the file never needs to be accessed again. – Cactusroot Mar 30 '22 at 20:45
No when you get it . You'll want to get it as a list of URi's and then access it.. – Narendra_Nath Mar 31 '22 at 03:06

score 0 · Answer 2 · answered Mar 30 '22 at 20:38

Getting your app directory (ContextWrapper is an Application/Activity/Service):

String dir = ContextWrapper#getFilesDir().getAbsolutePath();

Obtaining the complete file path:

String path = dir + "/" + fileName + ".anything";

Obtaining a file-object:

File file = new File(path);

Saving a byte array:

Files.write(dir, content);

Or a file:

FileWriter writer = new FileWriter(file);

In java, linebreaks use the character '\n', you can use that.

Load a byte array using String name:

Files.readAllBytes(path);

Or a file:

FileReader reader = new FileReader(file);

You'll have to come up for a system to name your files. To check if a file exists, just create the file object and call

file.exists() && !file.isDirectory()

For naming your files, you'll need to come up with a system. If recipeName is unique, you can use that. You'll find something that uniquely identifies your Recipe.

How to write to files in android studio? Where are the files stored?

2 Answers2