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I want to save a simple .txt file in Android and later I want to copy this file from the device to a PC where the device is mounted as a MTP-Device.

I own two Android Devices:

  • Nexus 4, Stock Android 5.0.1
  • Nexus 7 2012, CyanogenMod 12, Android 5.0.2

To make sure that it's not a Nexus device bug I tried a Wiko phone from a friend.

I use this code to save the file to the Downloads folder on the external storage. This is recommended on the developer page. 

private void saveData()
    {    
        String fileName = "test.txt";
        String writeString = "Hello World";
        File filePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
        File saveFile = new File(filePath, fileName);
        saveFile.setReadable(true);

        try
        {
            boolean result = saveFile.createNewFile();
            if(result == true)
            {
                Log.i(TAG, "File successfully created");
            }
            else
            {
                Log.i(TAG, "Error. File not created");
            }
            BufferedWriter writer = new BufferedWriter(new FileWriter(saveFile));
            writer.write(writeString);
            writer.close();
        }
        catch(Exception e)
        {
            Log.e(TAG,e.toString());
        }
    }

I use the following permissions: 

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

When I use MTP to connect to the device I get an empty download folder but when I access the folder through a File Browser in Android (in my case it's ES File Browser) I can see the file and the content. So I think creating the file and writing to it works.

When creating the file I receive the right Log: "File successfully created."

richsage
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DarkRettich
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  • The MTP relies on the MediaStore knowing the file. You should invoke the MediaScanner on your newly created file. http://stackoverflow.com/questions/14449509/how-to-invoke-android-media-scanner-for-vendor-provided-external-sd-card-not-th Switching off/on your device will do the trick too. Please put MTP in the subject of your post. – greenapps Apr 29 '15 at 13:54
  • thanks greenapps, that worked for me. – DarkRettich May 01 '15 at 07:26

1 Answers1

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You need to add the file to the MediaStore: (quite a lot of code...)

try {
    new MediaScannerConnectionClient() {
        private MediaScannerConnection mMs;

        public void init() {
            mMs = new MediaScannerConnection(myContext, this);
            mMs.connect();
        }

        @Override
        public void onMediaScannerConnected() {

            File pathFile = Environment
                   .getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
            File scanFile = new File(pathFile, "test.txt");

            mMs.scanFile(scanFile.getAbsolutePath(), null); // <-- repeat for all files

            mMs.disconnect();
        }

        @Override
        public void onScanCompleted(String path, Uri uri) {
        }

    }.init();
} catch(Exception e) {
    // Device does not support adding files manually. 
    // Sending Broadcast to start MediaScanner (slower than adding manually)
    try {   
        sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, 
                Uri.parse("file://" + Environment.getExternalStorageDirectory())));
    } catch(Exception ee) {
        // Something went terribly wrong. 
        // Can't add file to MediaStore and can't send Broadcast to start MediaScanner.
    }
}
ByteHamster
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    If you did found a solution, it would be very appreciated and useful for others, if you posted an answer by yourself and you marked it as accepted. :) – ocramot May 07 '15 at 09:48