Write a string to a file

Question

I want to write something to a file. I found this code:

private void writeToFile(String data) { 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()); } }

The code seems very logical, but I can't find the config.txt file in my phone.
How can I retrieve that file which includes the string?

Do you really need to write something into a txt file? If not consider using SharedPreferences. developer.android.com/guide/topics/data/data-storage.html#pref — Sebastian
– Sebastian, Commented Feb 18, 2016 at 13:07

Phantômaxx · Accepted Answer · 2017-12-02 16:42:07Z

Not having specified a path, your file will be saved in your app space (/data/data/your.app.name/).

Therefore, you better save your file onto an external storage (which is not necessarily the SD card, it can be the default storage).

You might want to dig into the subject, by reading the official docs

In synthesis:

Add this permission to your Manifest:

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

It includes the READ permission, so no need to specify it too.

Save the file in a location you specify (this is taken from my live cod, so I'm sure it works):

public void writeToFile(String data) { // Get the directory for the user's public pictures directory. final File path = Environment.getExternalStoragePublicDirectory ( //Environment.DIRECTORY_PICTURES Environment.DIRECTORY_DCIM + "/YourFolder/" ); // Make sure the path directory exists. if(!path.exists()) { // Make it, if it doesn't exit path.mkdirs(); } final File file = new File(path, "config.txt"); // Save your stream, don't forget to flush() it before closing it. try { file.createNewFile(); FileOutputStream fOut = new FileOutputStream(file); OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut); myOutWriter.append(data); myOutWriter.close(); fOut.flush(); fOut.close(); } catch (IOException e) { Log.e("Exception", "File write failed: " + e.toString()); } }

[EDIT] OK Try like this (different path - a folder on the external storage):

 String path = Environment.getExternalStorageDirectory() + File.separator + "yourFolder"; // Create the folder. File folder = new File(path); folder.mkdirs(); // Create the file. File file = new File(folder, "config.txt");

it's /data/data/... not data/data/... and it can't be seen with a file explorer, if you don't have root access.
I'm searching whole phone for config.txt, it can't find anything.
Do you have root access? If not, you can't find it. But you can re-read my updated answer, follow the provided link and save the file where you decide to save it.
Good answer but It really surprises me that every answer skips using a Buffer. For efficiency consider wrapping your OutputStreamWriter with a BufferedWriter.

murugan mani · Accepted Answer · 2018-11-30 04:59:25Z

Write one text file simplified:

private void writeToFile(String content) { try { File file = new File(Environment.getExternalStorageDirectory() + "/test.txt"); if (!file.exists()) { file.createNewFile(); } FileWriter writer = new FileWriter(file); writer.append(content); writer.flush(); writer.close(); } catch (IOException e) { } }

Hitesh Sahu · Accepted Answer · 2017-09-17 14:57:17Z

This Method takes File name & data String as Input and dumps them in a folder on SD card. You can change Name of the folder if you want.

The return type is Boolean depending upon Success or failure of the FileOperation.

Important Note: Try to do it in Async Task as FIle IO make cause ANR on Main Thread.

 public boolean writeToFile(String dataToWrite, String fileName) { String directoryPath = Environment.getExternalStorageDirectory() + File.separator + "LOGS" + File.separator; Log.d(TAG, "Dumping " + fileName +" At : "+directoryPath); // Create the fileDirectory. File fileDirectory = new File(directoryPath); // Make sure the directoryPath directory exists. if (!fileDirectory.exists()) { // Make it, if it doesn't exist if (fileDirectory.mkdirs()) { // Created DIR Log.i(TAG, "Log Directory Created Trying to Dump Logs"); } else { // FAILED Log.e(TAG, "Error: Failed to Create Log Directory"); return false; } } else { Log.i(TAG, "Log Directory Exist Trying to Dump Logs"); } try { // Create FIle Objec which I need to write File fileToWrite = new File(directoryPath, fileName + ".txt"); // ry to create FIle on card if (fileToWrite.createNewFile()) { //Create a stream to file path FileOutputStream outPutStream = new FileOutputStream(fileToWrite); //Create Writer to write STream to file Path OutputStreamWriter outPutStreamWriter = new OutputStreamWriter(outPutStream); // Stream Byte Data to the file outPutStreamWriter.append(dataToWrite); //Close Writer outPutStreamWriter.close(); //Clear Stream outPutStream.flush(); //Terminate STream outPutStream.close(); return true; } else { Log.e(TAG, "Error: Failed to Create Log File"); return false; } } catch (IOException e) { Log.e("Exception", "Error: File write failed: " + e.toString()); e.fillInStackTrace(); return false; } }

Community · Accepted Answer · 2020-06-20 09:12:55Z

You can write complete data in logData in File

The File will be create in Downlaods Directory

This is only for Api 28 and lower .

This will not work on Api 29 and higer

@TargetApi(Build.VERSION_CODES.P) public static File createPrivateFile(String logData) { String fileName = "/Abc.txt"; File directory = new File(Environment.getExternalStorageDirectory() + "/" + Environment.DIRECTORY_DOWNLOADS + "/"); directory.mkdir(); File file = new File(directory + fileName); FileOutputStream fos = null; try { if (file.exists()) { file.delete(); } file = new File(getAppDir() + fileName); file.createNewFile(); fos = new FileOutputStream(file); fos.write(logData.getBytes()); fos.flush(); fos.close(); return file; } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return null; }

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