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I want to convert this code for sounds (trying to share audio files)

I examined similar subjects, but I couldn't do it. I'm trying to share .mp3 file with LongClick button. I found it for JPEG files. One guy created method for sharing jpeg file. How can I convert it for .mp3 files?
package com.example.tunch.trap;
import...
public class sansar extends AppCompatActivity {
private String yardik;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_sansar);
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
yardik = createImageOnSDCard(R.raw.yardik_denizi);
final MediaPlayer yardikdenizi = MediaPlayer.create(this, R.raw.yardik_denizi);
Button btnYardik = (Button) findViewById(R.id.btnSansar_1);
btnYardik.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(yardikdenizi.isPlaying()){
yardikdenizi.seekTo(0);
}
yardikdenizi.start();
}
});
btnYardik.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
Uri path= FileProvider.getUriForFile(sansar.this, "com.example.tunch.trap", new File(yardik));
Intent shareYardik = new Intent();
shareYardik.setAction(Intent.ACTION_SEND);
shareYardik.putExtra(Intent.EXTRA_TEXT,"Bu ses dosyasını gönderiyorum");
shareYardik.putExtra(Intent.EXTRA_STREAM, path);
shareYardik.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
shareYardik.setType("audio/mp3");
startActivity(Intent.createChooser(shareYardik, "Paylas.."));
return true;
}
});
}
private String createImageOnSDCard(int resID) {
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), resID);
String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES) + "/" + resID +".mp3";
File file = new File(path);
try {
OutputStream out = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
out.flush();
out.close();
}
catch (Exception e){
e.printStackTrace();
}
return file.getPath();
}
}
This is all Java code. createImageOnSDCard method is for images. I want to use it for my audio file (yardik_denizi.mp3). When I run this, it works but program is trying to send jpeg file. So it doesn't work literally :) How should I change that last part?

You need a method that copies a private raw resource content (R.raw.yardik_denizi) to a publicly readable file such that the latter can be shared with other applications:
public void copyPrivateRawResuorceToPubliclyAccessibleFile(#RawRes int resID,
#NonNull String outputFile) {
InputStream inputStream = null;
FileOutputStream outputStream = null;
try {
inputStream = getResources().openRawResource(resID);
outputStream = openFileOutput(outputFile, Context.MODE_WORLD_READABLE
| Context.MODE_APPEND);
byte[] buffer = new byte[1024];
int length = 0;
try {
while ((length = inputStream.read(buffer)) > 0) {
outputStream.write(buffer, 0, length);
}
} catch (IOException ioe) {
/* ignore */
}
} catch (FileNotFoundException fnfe) {
/* ignore */
} finally {
try {
inputStream.close();
} catch (IOException ioe) {
/* ignore */
}
try {
outputStream.close();
} catch (IOException ioe) {
/* ignore */
}
}
}
and then:
copyPrivateRawResuorceToPubliclyAccessibleFile(R.raw.yardik_denizi, "sound.mp3");
final Intent shareIntent = new Intent(Intent.ACTION_SEND);
shareIntent.setType("audio/*");
Uri uri = Uri.fromFile(getFileStreamPath("sound.mp3"));
shareIntent.putExtra(Intent.EXTRA_STREAM, uri);
startActivity(Intent.createChooser(shareIntent, "Share Sound File"));

You should change the path for uri at
Uri path= FileProvider.getUriForFile(sansar.this, "com.example.tunch.trap", new File(change_it_path_to_yardik_denizi.mp3));

Finally i got the answer. I can send mp3 files to other apps with this code.
copyFiletoExternalStorage(R.raw.yardik_denizi, "yardik_denizi.mp3");
Uri path= FileProvider.getUriForFile(sansar.this,
"com.example.tunch.trap", new File(Environment.getExternalStorageDirectory() +
"/Android/data/yardik_denizi.mp3"));
Intent shareYardik = new Intent();
shareYardik.setAction(Intent.ACTION_SEND);
shareYardik.putExtra(Intent.EXTRA_TEXT,"Bu ses dosyasını gönderiyorum");
shareYardik.putExtra(Intent.EXTRA_STREAM, path);
shareYardik.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
shareYardik.setType("audio/mp3");
startActivity(Intent.createChooser(shareYardik, "Paylas.."));
And need to create a method to save data in external store.
private void copyFiletoExternalStorage (int resourceId, String resourceName){
String pathSDCard = Environment.getExternalStorageDirectory() + "/Android/data/"
+ resourceName;
try{
InputStream in = getResources().openRawResource(resourceId);
FileOutputStream out = null;
out = new FileOutputStream(pathSDCard);
byte[] buff = new byte[1024];
int read = 0;
try {
while ((read = in.read(buff)) > 0) {
out.write(buff, 0, read);
}
} finally {
in.close();
out.close();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

android conver video to bytearray

i try to conver video from sd card in byte array.i wrote code ,but i am doing something wrong.what is a wrong in my code ? i have no idea what i am doing wrong
this is a my source
public byte[] readBytes(Uri uri) throws IOException {
InputStream inputStream = getContentResolver().openInputStream(uri);
ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();
int bufferSize = 1024;
byte[] buffer = new byte[bufferSize];
int len = 0;
while ((len = inputStream.read(buffer)) != -1) {
byteBuffer.write(buffer, 0, len);
}
return byteBuffer.toByteArray();
}
upload_btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
String fileName = "video.mp4";
String completePath = Environment.getExternalStorageDirectory()
+ "/" + fileName;
File file = new File(completePath);
Uri imageUri = Uri.fromFile(file);
try {
byte[] bytes = readBytes(imageUri);
Log.e("Byte Array is", String.valueOf(bytes));
Toast.makeText(getApplicationContext(),
String.valueOf(bytes), Toast.LENGTH_LONG).show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
i run my app and result is small streang,not byte array

Problems understanding context and contextwrapper

I'm not able to understand these classes. I've been trying to create a new file in a new directory on my internal storage, put some text in it and then to read it out. This does not seem to work without the ContextWrapper. So I tried this:
public class DownloadActivity extends Activity {
...
class Download extends AsyncTask<String, Void, String>{
....
private void searchAndSave(String s) throws IOException {
....
ContextWrapper cw = new ContextWrapper(getBaseContext());
File folder = cw.getDir("folder", Context.MODE_PRIVATE);
File fileInFolder = new File(folder, "fileInFolder");
String string = "Hello world!";
FileOutputStream outputStream = openFileOutput("fileInFolder",
Context.MODE_PRIVATE);
outputStream.write(string.getBytes());
outputStream.close();
File fl = new File(cw.getDir("folder", Context.MODE_PRIVATE)+"/fileInFolder");
FileInputStream fin = new FileInputStream(fl);
BufferedReader reader = new BufferedReader(
new InputStreamReader(fin));
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line).append("\n");
}
String result = sb.toString();
reader.close();
fin.close();
}
}
Creating the file does not work without the ContextWrapper. I've been reading a lot, but I still have problems to understand, what the Context and the Contextwrapper actually do and why I need them to create a file. Additionally in my code the creating of the FileInputStream does not work. When the program reaches
FileInputStream fin = new FileInputStream(fl);
I always get the error:
05-21 11:18:25.721: W/System.err(7344): java.io.FileNotFoundException:
/data/data/com.example.dice/app_folder/fileInFolder: open failed:
ENOENT (No such file or directory)
I really would appreciate some help with understanding and solving this problem.
UPDATE: I made a more spare Activity, maybe now it's easier to reconstruct the whole thing. (Should I have done this in a new answer, or is it okay to edit my first posting?) Even though I don't get an error message when trying to create a file, is doesn't seem to work. Here I try reading the "Hello world" string, but I get a FileNotFoundException (EISDIR). Just for you to know :)
public class FolderActivity extends Activity {
public final static String TAG = "FolderActivity";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_folder);
Button button = (Button) findViewById(R.id.button_folder);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
try {
folder();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
private void folder() throws IOException{
Log.d(TAG, "folder");
ContextWrapper cw = new ContextWrapper(getBaseContext());
Log.d(TAG, "cw = new ContextWrapper");
File folder = cw.getDir("folder", Context.MODE_PRIVATE);
Log.d(TAG, "folder = cw.getDir");
File fileInFolder = new File(folder, "fileInFolder");
Log.d(TAG, "fileInFolder = new File");
/*Log.d(TAG,
"fileInFolder.getAbsolutePath()"
+ fileInFolder.getAbsolutePath());*/
String string = "Hello world!";
// Aksioms suggestion
if (!fileInFolder.exists() && !fileInFolder.mkdirs()) {
Log.e("file", "Couldn't create file " + fileInFolder);
} else { Log.d(TAG, "file created"); }
FileOutputStream outputStream = openFileOutput("fileInFolder",
Context.MODE_PRIVATE);
outputStream.write(string.getBytes());
outputStream.close();
Log.d(TAG,
"fileInFolder.getAbsolutePath()"
+ fileInFolder.getAbsolutePath());
String s = fileInFolder.getAbsolutePath();
try {
getStringFromFile(s);
} catch (Exception e) {
e.printStackTrace();
}
}
public static String getStringFromFile (String filePath) throws Exception {
File fl = new File(filePath);
FileInputStream fin = new FileInputStream(fl);
String ret = convertStreamToString(fin);
//Make sure you close all streams.
fin.close();
return ret;
}
public static String convertStreamToString(InputStream is) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line).append("\n");
}
reader.close();
return sb.toString();
}
}

You are trying to open a file which does not exists.
Make sure that you check and create the file if it does not exsist:
if (!fl.exists() && !fl.mkdirs()) {
Log.e("file", "Couldn't create file " + fl);
}
EDIT:
Yes the getDir creats the folder if it is not created.
File folder = cw.getDir("folder", Context.MODE_PRIVATE);
But the problem is here
File fileInFolder = new File(folder, "fileInFolder");
String string = "Hello world!";
FileOutputStream outputStream = openFileOutput("fileInFolder",
Context.MODE_PRIVATE);
In here you try to open a file that does not exsist, you just constructed a new file named fileInFolder, but you actually do not have that folder yet.
Try to use the code that I wrote at the first place, before the openFileOutput("fileInFolder", Context.MODE_PRIVATE); :
if (!fileInFolder.exists() && !fileInFolder.mkdirs()) {
Log.e("file", "Couldn't create file " + fileInFolder);
}
Try this and tell me how it goes.
EDIT 2:
OK I found the problem it was so obvious. The mistake was that we created the fileInFolder as a directory, and you can not write anything there :D
What we should have done is this:
Remove my code for creating the fileInFolder.
if (!fileInFolder .exists() && !fileInFolder .mkdirs()) {
Log.e("file", "Couldn't create file " + fileInFolder );
} else {
Log.d(TAG, "file created");
}
we do not need to create it because we will use it as a file. So the change I have made in your code is this:
FileOutputStream outputStream = new FileOutputStream(fileInFolder);
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(outputStream));
out.write(string);
out.close();
Add this between the line String string = "Hello world!"; and the first Log.d... This is the correct way to write in a file.
The whole code:
public class MainActivity extends Activity {
public final static String TAG = "FolderActivity";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button) findViewById(R.id.button_folder);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
try {
folder();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
private void folder() throws IOException {
Log.d(TAG, "folder");
ContextWrapper cw = new ContextWrapper(getBaseContext());
Log.d(TAG, "cw = new ContextWrapper");
File folder = cw.getDir("folder", Context.MODE_PRIVATE);
Log.d(TAG, "folder = cw.getDir");
File fileInFolder = new File(folder, "fileInFolder");
Log.d(TAG, "fileInFolder = new File");
/*
* Log.d(TAG, "fileInFolder.getAbsolutePath()" +
* fileInFolder.getAbsolutePath());
*/
String string = "Hello world!";
FileOutputStream outputStream = new FileOutputStream(fileInFolder);
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(outputStream));
out.write(string);
out.close();
Log.d(TAG,
"fileInFolder.getAbsolutePath()"
+ fileInFolder.getAbsolutePath());
String s = fileInFolder.getAbsolutePath();
try {
getStringFromFile(s);
} catch (Exception e) {
e.printStackTrace();
}
}
public static String getStringFromFile(String filePath) throws Exception {
File fl = new File(filePath);
FileInputStream fin = new FileInputStream(fl);
String ret = convertStreamToString(fin);
// Make sure you close all streams.
fin.close();
return ret;
}
public static String convertStreamToString(InputStream is) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line).append("\n");
}
reader.close();
return sb.toString();
}}
Check if you have this permission in your manifest:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
I hope everything is clear now.

Read a image string from external file in android

i am making android application ..in which i have encoded my image string to external file in external card..But when i read that file to show image....application crashed..
here is a code:
storedpic.setOnClickListener(new View.OnClickListener() {
ImageView storedimageView = (ImageView) findViewById(R.id.imageView3);
public void onClick(View v) {
File sdcard = Environment.getExternalStorageDirectory();
File readfile = new File(sdcard, "myfile.txt");
try {
BufferedReader br = new BufferedReader(new FileReader(readfile));
String test;
while (true) {
test = br.readLine();
// readLine() returns null if no more lines in the file
byte[] bytarray = Base64.decode(test, Base64.DEFAULT);
Bitmap bmimage = BitmapFactory
.decodeByteArray(bytarray, 0, bytarray.length);
storedimageView.setImageBitmap(bmimage);
if (test == null)
break;
}
}
catch (IOException e) {
Toast.makeText(getBaseContext(), "Can't read a file", Toast.LENGTH_LONG).show();
}
}
});

More than likely Base64#decode is throwing an NPE as the input String is null. Try replacing
while (true) {
test = br.readLine();
...
}
with
while ((test = br.readLine()) != null) {
...
}
Of course remove the break statement

Read/Write String from/to a File in Android

I want to save a file to the internal storage by getting the text inputted from EditText. Then I want the same file to return the inputted text in String form and save it to another String which is to be used later.
Here's the code:
package com.omm.easybalancerecharge;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText num = (EditText) findViewById(R.id.sNum);
Button ch = (Button) findViewById(R.id.rButton);
TelephonyManager operator = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
String opname = operator.getNetworkOperatorName();
TextView status = (TextView) findViewById(R.id.setStatus);
final EditText ID = (EditText) findViewById(R.id.IQID);
Button save = (Button) findViewById(R.id.sButton);
final String myID = ""; //When Reading The File Back, I Need To Store It In This String For Later Use
save.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
//Get Text From EditText "ID" And Save It To Internal Memory
}
});
if (opname.contentEquals("zain SA")) {
status.setText("Your Network Is: " + opname);
} else {
status.setText("No Network");
}
ch.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
//Read From The Saved File Here And Append It To String "myID"
String hash = Uri.encode("#");
Intent intent = new Intent(Intent.ACTION_CALL);
intent.setData(Uri.parse("tel:*141*" + /*Use The String With Data Retrieved Here*/ num.getText()
+ hash));
startActivity(intent);
}
});
}
I have included comments to help you further analyze my points as to where I want the operations to be done/variables to be used.

Hope this might be useful to you.
Write File:
private void writeToFile(String data,Context context) {
try {
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(context.openFileOutput("config.txt", Context.MODE_PRIVATE));
outputStreamWriter.write(data);
outputStreamWriter.close();
}
catch (IOException e) {
Log.e("Exception", "File write failed: " + e.toString());
}
}
Read File:
private String readFromFile(Context context) {
String ret = "";
try {
InputStream inputStream = context.openFileInput("config.txt");
if ( inputStream != null ) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String receiveString = "";
StringBuilder stringBuilder = new StringBuilder();
while ( (receiveString = bufferedReader.readLine()) != null ) {
stringBuilder.append("\n").append(receiveString);
}
inputStream.close();
ret = stringBuilder.toString();
}
}
catch (FileNotFoundException e) {
Log.e("login activity", "File not found: " + e.toString());
} catch (IOException e) {
Log.e("login activity", "Can not read file: " + e.toString());
}
return ret;
}

For those looking for a general strategy for reading and writing a string to file:
First, get a file object
You'll need the storage path. For the internal storage, use:
File path = context.getFilesDir();
For the external storage (SD card), use:
File path = context.getExternalFilesDir(null);
Then create your file object:
File file = new File(path, "my-file-name.txt");
Write a string to the file
FileOutputStream stream = new FileOutputStream(file);
try {
stream.write("text-to-write".getBytes());
} finally {
stream.close();
}
Or with Google Guava
String contents = Files.toString(file, StandardCharsets.UTF_8);
Read the file to a string
int length = (int) file.length();
byte[] bytes = new byte[length];
FileInputStream in = new FileInputStream(file);
try {
in.read(bytes);
} finally {
in.close();
}
String contents = new String(bytes);
Or if you are using Google Guava
String contents = Files.toString(file,"UTF-8");
For completeness I'll mention
String contents = new Scanner(file).useDelimiter("\\A").next();
which requires no libraries, but benchmarks 50% - 400% slower than the other options (in various tests on my Nexus 5).
Notes
For each of these strategies, you'll be asked to catch an IOException.
The default character encoding on Android is UTF-8.
If you are using external storage, you'll need to add to your manifest either:
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
or
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
Write permission implies read permission, so you don't need both.

public static void writeStringAsFile(final String fileContents, String fileName) {
Context context = App.instance.getApplicationContext();
try {
FileWriter out = new FileWriter(new File(context.getFilesDir(), fileName));
out.write(fileContents);
out.close();
} catch (IOException e) {
Logger.logError(TAG, e);
}
}
public static String readFileAsString(String fileName) {
Context context = App.instance.getApplicationContext();
StringBuilder stringBuilder = new StringBuilder();
String line;
BufferedReader in = null;
try {
in = new BufferedReader(new FileReader(new File(context.getFilesDir(), fileName)));
while ((line = in.readLine()) != null) stringBuilder.append(line);
} catch (FileNotFoundException e) {
Logger.logError(TAG, e);
} catch (IOException e) {
Logger.logError(TAG, e);
}
return stringBuilder.toString();
}

Just a a bit modifications on reading string from a file method for more performance
private String readFromFile(Context context, String fileName) {
if (context == null) {
return null;
}
String ret = "";
try {
InputStream inputStream = context.openFileInput(fileName);
if ( inputStream != null ) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
int size = inputStream.available();
char[] buffer = new char[size];
inputStreamReader.read(buffer);
inputStream.close();
ret = new String(buffer);
}
}catch (Exception e) {
e.printStackTrace();
}
return ret;
}

The Kotlin way by using builtin Extension function on File
Write: yourFile.writeText(textFromEditText)
Read: yourFile.readText()

check the below code.
Reading from a file in the filesystem.
FileInputStream fis = null;
try {
fis = context.openFileInput(fileName);
InputStreamReader isr = new InputStreamReader(fis);
// READ STRING OF UNKNOWN LENGTH
StringBuilder sb = new StringBuilder();
char[] inputBuffer = new char[2048];
int l;
// FILL BUFFER WITH DATA
while ((l = isr.read(inputBuffer)) != -1) {
sb.append(inputBuffer, 0, l);
}
// CONVERT BYTES TO STRING
String readString = sb.toString();
fis.close();
catch (Exception e) {
} finally {
if (fis != null) {
fis = null;
}
}
below code is to write the file in to internal filesystem.
FileOutputStream fos = null;
try {
fos = context.openFileOutput(fileName, Context.MODE_PRIVATE);
fos.write(stringdatatobestoredinfile.getBytes());
fos.flush();
fos.close();
} catch (Exception e) {
} finally {
if (fos != null) {
fos = null;
}
}
I think this will help you.

I'm a bit of a beginner and struggled getting this to work today.
Below is the class that I ended up with. It works but I was wondering how imperfect my solution is. Anyway, I was hoping some of you more experienced folk might be willing to have a look at my IO class and give me some tips. Cheers!
public class HighScore {
File data = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator);
File file = new File(data, "highscore.txt");
private int highScore = 0;
public int readHighScore() {
try {
BufferedReader br = new BufferedReader(new FileReader(file));
try {
highScore = Integer.parseInt(br.readLine());
br.close();
} catch (NumberFormatException | IOException e) {
e.printStackTrace();
}
} catch (FileNotFoundException e) {
try {
file.createNewFile();
} catch (IOException ioe) {
ioe.printStackTrace();
}
e.printStackTrace();
}
return highScore;
}
public void writeHighScore(int highestScore) {
try {
BufferedWriter bw = new BufferedWriter(new FileWriter(file));
bw.write(String.valueOf(highestScore));
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

Kotlin
class FileReadWriteService {
private var context:Context? = ContextHolder.instance.appContext
fun writeFileOnInternalStorage(fileKey: String, sBody: String) {
val file = File(context?.filesDir, "files")
try {
if (!file.exists()) {
file.mkdir()
}
val fileToWrite = File(file, fileKey)
val writer = FileWriter(fileToWrite)
writer.append(sBody)
writer.flush()
writer.close()
} catch (e: Exception) {
Logger.e(classTag, e)
}
}
fun readFileOnInternalStorage(fileKey: String): String {
val file = File(context?.filesDir, "files")
var ret = ""
try {
if (!file.exists()) {
return ret
}
val fileToRead = File(file, fileKey)
val reader = FileReader(fileToRead)
ret = reader.readText()
reader.close()
} catch (e: Exception) {
Logger.e(classTag, e)
}
return ret
}
}

the first thing we need is the permissions in AndroidManifest.xml
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
so in an asyncTask Kotlin class, we treat the creation of the file
import android.os.AsyncTask
import android.os.Environment
import android.util.Log
import java.io.*
class WriteFile: AsyncTask<String, Int, String>() {
private val mFolder = "/MainFolder"
lateinit var folder: File
internal var writeThis = "string to cacheApp.txt"
internal var cacheApptxt = "cacheApp.txt"
override fun doInBackground(vararg writethis: String): String? {
val received = writethis[0]
if(received.isNotEmpty()){
writeThis = received
}
folder = File(Environment.getExternalStorageDirectory(),"$mFolder/")
if(!folder.exists()){
folder.mkdir()
val readME = File(folder, cacheApptxt)
val file = File(readME.path)
val out: BufferedWriter
try {
out = BufferedWriter(FileWriter(file, true), 1024)
out.write(writeThis)
out.newLine()
out.close()
Log.d("Output_Success", folder.path)
} catch (e: Exception) {
Log.d("Output_Exception", "$e")
}
}
return folder.path
}
override fun onPostExecute(result: String) {
super.onPostExecute(result)
if(result.isNotEmpty()){
//implement an interface or do something
Log.d("onPostExecuteSuccess", result)
}else{
Log.d("onPostExecuteFailure", result)
}
}
}
Of course if you are using Android above Api 23, you must handle the request to allow writing to device memory. Something like this
import android.Manifest
import android.content.Context
import android.content.pm.PackageManager
import android.os.Build
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
class ReadandWrite {
private val mREAD = 9
private val mWRITE = 10
private var readAndWrite: Boolean = false
fun readAndwriteStorage(ctx: Context, atividade: AppCompatActivity): Boolean {
if (Build.VERSION.SDK_INT < 23) {
readAndWrite = true
} else {
val mRead = ContextCompat.checkSelfPermission(ctx, Manifest.permission.READ_EXTERNAL_STORAGE)
val mWrite = ContextCompat.checkSelfPermission(ctx, Manifest.permission.WRITE_EXTERNAL_STORAGE)
if (mRead != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(atividade, arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE), mREAD)
} else {
readAndWrite = true
}
if (mWrite != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(atividade, arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE), mWRITE)
} else {
readAndWrite = true
}
}
return readAndWrite
}
}
then in an activity, execute the call.
var pathToFileCreated = ""
val anRW = ReadandWrite().readAndwriteStorage(this,this)
if(anRW){
pathToFileCreated = WriteFile().execute("onTaskComplete").get()
Log.d("pathToFileCreated",pathToFileCreated)
}

We can use this code to write String to a file
public static void writeTextToFile(final String filename, final String data) {
File file = new File(filename);
try {
FileOutputStream stream = new FileOutputStream(file);
stream.write(data.getBytes());
stream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
Then in the Main code, we use this, for example
writeTextToFile(getExternalFilesDir("/").getAbsolutePath() + "/output.txt", "my-example-text");
After that, check the file at Android/data/<package-name>/files.

The easiest way to append to a text file in kotlin:
val directory = File(context.filesDir, "LogsToSendToNextMunich").apply {
mkdirs()
}
val file = File(directory,"Logs.txt")
file.appendText("You new text")
If you want to just write to the file:
yourFile.writeText("You new text")
writing anything to the files, using bytes:
FileOutputStream(file).use {
it.write("Some text for example".encodeToByteArray())
}