Writing a file to Android SD card

Question

Right now I am trying to make an application that basically creates 100 files on SD card using a for loop.

I have looked into a lot of related questions and posts and I can't happen to solve it myself. I am using Android Studio's built-in emulator as my testing device since I prefer not to run it on my actual phone...

Anyway I created a button which if you click, it produces 100 files on external storage (well that's my intention though -_-).

So far I have this,

for (int i=1; i <= 100; i++) {
 sdPath = Environment.getExternalStorageDirectory() + "/Android/";
 File file = new Files(sdPath + "hacked" + i);
  try{
    FileOutputStream fos = new FileOutputStream(file);
     fos.close();
     }catch (Exception e){Log.i("Failed to save", e.getMessage());
    }

This is the main implementation of file creation so far. I have edited my Manifest to include permission to write external storage but every time when I run the application I get /sotrage/0B01-3415/Android/hacked 1-100: open failed: EACCESS (Permission denied) message.

Does anyone happen to know what is causing the trouble???

Also what I don't understand is, when we use Environment.getExternalStorageDirectory, what does it really mean? In my actual phone, directories are like /sdcard/Android/data .... like this form.

score 1 · Answer 1 · edited May 23 '17 at 11:50

This is your need

public void createFiles(View view)
{

    String path = new String(Environment.getExternalStorageDirectory().getAbsolutePath() + "/AndroidSample/");

    boolean res;

    for(int i = 1; i <= 100; i++) {
        path += String.valueOf(i);
        File file = new File(path);
        if (!file.exists()) {
            res = file.mkdirs();
        } else {
            res = false;
        }
        if(res == true)
        Log.d("File Created", String.valueOf(i));
    }
}

Add These Two Permissions on Manifest xml file android.permission.WRITE_EXTERNAL_STORAGE and android.permission.READ_EXTERNAL_STORAGE

To add permission in manifest refer this

Remember file names are going like 1, 12, 123,....

score 0 · Answer 2 · answered Mar 02 '16 at 06:03

Have you declared permission at right place in manifest file as

<manifest>
    <application>
        ...

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

Hope it helps you.

zeeali · Answer 3 · 2016-03-02T06:42:03.420

Try with following code:

String path = Environment.getExternalStorageDirectory().getAbsolutePath().toString();

for (int i=1; i <= 100; i++) {
    File file = new File(path, "/Android/" + "hacked" + System.currentTimeMillis() + "");

    try {
        if (!file.exists()) {
            file.createNewFile();
        }
    } catch (Exception e) {
        String errorMessage = "Your device doesn't support this action!";
        Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT);
        toast.show();
    }
}

Declare following permissions in Manifest file:

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

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

Writing a file to Android SD card

3 Answers3