How to list files in an android directory?

Question

Here's my code so far:

String path = Environment.getExternalStorageDirectory().toString()+"/Pictures";

        AssetManager mgr = getAssets();

        try {

            String list[] = mgr.list(path);
            Log.e("FILES", String.valueOf(list.length));

            if (list != null)
                for (int i=0; i<list.length; ++i)
                    {
                        Log.e("FILE:", path +"/"+ list[i]);
                    }

        } catch (IOException e) {
            Log.v("List error:", "can't list" + path);
        }

Yet while I do have files in that dir, it returns me list.length = 0... any ideas?

score 391 · Accepted Answer · edited Nov 22 '19 at 13:27

391

In order to access the files, the permissions must be given in the manifest file.

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

Try this:

String path = Environment.getExternalStorageDirectory().toString()+"/Pictures";
Log.d("Files", "Path: " + path);
File directory = new File(path);
File[] files = directory.listFiles();
Log.d("Files", "Size: "+ files.length);
for (int i = 0; i < files.length; i++)
{
    Log.d("Files", "FileName:" + files[i].getName());
}

edited Nov 22 '19 at 13:27

Noman

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answered Dec 27 '11 at 17:24

Yury

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7

Thanks Yury, strangely file.length gives a NullPointerException... any ideas? Spasibo! – Roger Travis Dec 27 '11 at 17:36
9

I think that you do not have files in the specified folder. Try to check file[] for null. If it is null then you do not have any results and file.length causes the exception. – Yury Dec 27 '11 at 17:41
4

Appears it was just missing a "/" :) Thanks! – Roger Travis Dec 27 '11 at 17:45
2

Worked like Charm! My mobile is Moto G4, **Android N**. If anyone are facing `can't play video error`. You need to go to your mobile `settings --> apps --> your app --> permissions --> enable storage.` Should do this manually if you are facing this error. Make sure that you have `` in your manifest. For the people who are facing `NullPointerException` - you are trying to access the files in the app's internal storage which are private sorry you can't do that. – coderpc Jun 23 '17 at 16:00
is there something like fileList().clear();? , so i can reuse this method – user55924 Mar 12 '18 at 02:48
if file.length gives NullPointerException even after adding permission in manifest file, go to your app settings and allow storage permission manually – Sumit Jun 11 '21 at 13:20

score 49 · Answer 2 · answered Aug 20 '14 at 13:32

49

I just discovered that:

new File("/sdcard/").listFiles() returns null if you do not have:

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

set in your AndroidManifest.xml file.

answered Aug 20 '14 at 13:32

Dan Brough

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I know this is truth, but... Is this an answer? Or should be a comment? – Joaquin Iurchuk Dec 09 '15 at 17:10
7

In addition, on Android 6.0+ the permission needs to be granted in Settings->Apps->Your app->Permissions. – vt. Jan 31 '16 at 23:57
1

It also return null if Directory is empty – Hitesh Sahu May 26 '16 at 04:33

score 17 · Answer 3 · answered Dec 27 '11 at 17:29

17

Well, the AssetManager lists files within the assets folder that is inside of your APK file. So what you're trying to list in your example above is [apk]/assets/sdcard/Pictures.

If you put some pictures within the assets folder inside of your application, and they were in the Pictures directory, you would do mgr.list("/Pictures/").

On the other hand, if you have files on the sdcard that are outside of your APK file, in the Pictures folder, then you would use File as so:

File file = new File(Environment.getExternalStorageDirectory(), "Pictures");
File[] pictures = file.listFiles();
...
for (...)
{
log.e("FILE:", pictures[i].getAbsolutePath());
}

And relevant links from the docs:
File
Asset Manager

answered Dec 27 '11 at 17:29

Reed

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Tried that "File[] pictures = file.listFiles();", but it also gives a NullPointException... hmm... – Roger Travis Dec 27 '11 at 17:42
1

Appears it was just missing a "/" :) Thanks! – Roger Travis Dec 27 '11 at 17:45
1

Thanks for saving my day :) – Syed Nazar Muhammad Mar 01 '16 at 15:12
@SyedNazarMuhammad Ha. And thank you for saving mine, my friend. Always enjoy a positive remark :D – Reed Mar 02 '16 at 18:21

score 13 · Answer 4 · answered Mar 05 '16 at 11:38

In addition to all the answers above:

If you are on Android 6.0+ (API Level 23+) you have to explicitly ask for permission to access external storage. Simply having

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

in your manifest won't be enough. You also have actively request the permission in your activity:

//check for permission
if(ContextCompat.checkSelfPermission(this,
            Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED){
    //ask for permission
    requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, READ_EXTERNAL_STORAGE_PERMISSION_CODE);
}

I recommend reading this: http://developer.android.com/training/permissions/requesting.html#perm-request

score 3 · Answer 5 · answered Oct 20 '20 at 07:57

Updated working method

My minSdkversion is 21, so I'm using ContextCompat.checkSelfPermission() method to grant permissions apart from also adding the <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/> in manifest. Thus, to get rid of the NullPointerException in spite of having files in your targeted directory, grant permissions as follows:-

MainActivity.java

public class MainActivity extends AppCompatActivity {
    /*Other variables & constants here*/  
    private final int READ_EXTERNAL_STORAGE=100;

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

        // ignore the button code

        Button btn = (Button) findViewById(R.id.button);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                openWebView();
            }
        });
    

         /*---------------------------- GRANT PERMISSIONS START-------------------------*/
        // Main part to grant permission. Handle other cases of permission denied
       //   yourself.
        if(ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)
            ActivityCompat.requestPermissions(this,new String[] {Manifest.permission.READ_EXTERNAL_STORAGE},READ_EXTERNAL_STORAGE);

         /*---------------------------- GRANT PERMISSIONS OVER-------------------------*/
   }

And the function that list all the files (in MainActivity.java), thanks to @Yury:-

public void getDownloadedFile() {
        String path = Environment.getExternalStorageDirectory().toString()+"/Download/";
        Log.d("Files", "Path: " + path);
        File directory = new File(path);
        File[] files = directory.listFiles();
        if(directory.canRead() && files!=null) {
            Log.d("Files", "Size: " + files.length);
            for(File file: files)
                Log.d("FILE",file.getName());
        }
        else
            Log.d("Null?", "it is null");
    }

raghav-wd · Answer 6 · 2021-07-17T07:11:36.773

2

Yury's answer needs some elaboration for newer versions of Android.

First, make sure to defined READ_EXTERNAL_STORAGE permission in manifest file.

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

Include the below, for SDK greater than or equals to Android 10(Q).

<application android:requestLegacyExternalStorage="true"...</application>

Now you can list files in a directory.

String path = Environment.getExternalStorageDirectory().toString()+"/Pictures";
Log.d("Files", "Path: " + path);
File directory = new File(path);
File[] files = directory.listFiles();
Log.d("Files", "Size: "+ files.length);
for (int i = 0; i < files.length; i++)
{
    Log.d("Files", "FileName:" + files[i].getName());
}

edited Jul 17 '21 at 07:11

answered Jul 15 '21 at 11:14

raghav-wd

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You should probably reference @Yury's original, accepted answer, as you have copied 90% of it and simply added the update for Android 10. – c.fogelklou Jul 15 '21 at 12:51
I'm new to stack overflow as a contributor, I had this problem and thought his answer was not complete so posted this. I'll wait for more views on it if people don't find it helpful I'll remove it, thanx mate for your view appreciate it! – raghav-wd Jul 15 '21 at 20:35
I think your answer would be OK if you stated that Yuri's answer needs some elaboration for newer versions of Android. – c.fogelklou Jul 16 '21 at 06:08

score 2 · Answer 7 · answered Dec 27 '11 at 17:25

2

Your path is not within the assets folder. Either you enumerate files within the assets folder by means of AssetManager.list() or you enumerate files on your SD card by means of File.list()

answered Dec 27 '11 at 17:25

Alexander Kulyakhtin

47,782
38
107
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score 1 · Answer 8 · answered Aug 11 '15 at 11:26

1

String[] listOfFiles = getActivity().getFilesDir().list();

or

String[] listOfFiles = Environment.getExternalStoragePublicDirectory (Environment.DIRECTORY_DOWNLOADS).list();

answered Aug 11 '15 at 11:26

rdkit

246
3
16

score 1 · Answer 9 · edited Jan 20 '16 at 03:52

Try this:

public class GetAllFilesInDirectory {

public static void main(String[] args) throws IOException {

    File dir = new File("dir");

    System.out.println("Getting all files in " + dir.getCanonicalPath() + " including those in subdirectories");
    List<File> files = (List<File>) FileUtils.listFiles(dir, TrueFileFilter.INSTANCE, TrueFileFilter.INSTANCE);
    for (File file : files) {
        System.out.println("file: " + file.getCanonicalPath());
    }

}

}

score 1 · Answer 10 · answered Feb 22 '16 at 11:44

There are two things that could be happening:

You are not adding READ_EXTERNAL_STORAGE permission to your AndroidManifest.xml
You are targeting Android 23 and you're not asking for that permission to the user. Go down to Android 22 or ask the user for that permission.

score 0 · Answer 11 · answered Nov 27 '18 at 07:05

Try these

 String appDirectoryName = getResources().getString(R.string.app_name);
    File directory = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/" + getResources().getString(R.string.app_name));
    directory.mkdirs();
    File[] fList = directory.listFiles();
    int a = 1;
    for (int x = 0; x < fList.length; x++) {

        //txt.setText("You Have Capture " + String.valueOf(a) + " Photos");
        a++;
    }
    //get all the files from a directory
    for (File file : fList) {
        if (file.isFile()) {
            list.add(new ModelClass(file.getName(), file.getAbsolutePath()));
        }
    }

score 0 · Answer 12 · answered Mar 11 '20 at 13:30

If you are on Android 10/Q and you did all of the correct things to request access permissions to read external storage and it still doesn't work, it's worth reading this answer:

Android Q (10) ask permission to get access all storage. Scoped storage

I had working code, but me device took it upon itself to update when it was on a network connection (it was usually without a connection.) Once in Android 10, the file access no longer worked. The only easy way to fix it without rewriting the code was to add that extra attribute to the manifest as described. The file access now works as in Android 9 again. YMMV, it probably won't continue to work in future versions.

score 0 · Answer 13 · edited Mar 06 '22 at 16:26

0

For the people are still getting NullPointerException when they try to get file list, if you using Android API 29+ then you need to add

<application android:requestLegacyExternalStorage="true"...

in your AndroidManifest.xml file.

Then request for storage permission again.

edited Mar 06 '22 at 16:26

Abhishek Dutt

1,308
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answered Mar 02 '22 at 09:50

Lasith M

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score 0 · Answer 14 · answered May 01 '22 at 11:02

0

Simple way to list files in android device in a specific folder

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

IN Kotlin

val fileRoot = Environment.getExternalStorageDirectory()
val yourDir = File(fileRoot, "FOLDER_NAME")
    for (f in yourDir.listFiles()!!) {
       if (f.isFile){
           print(f.name)
       }
    }

All the file name will be printed with the file extension

answered May 01 '22 at 11:02

Rohit S

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If you use `!!`, you can have NPE. In this case check that `yourDir.listFiles()` is not null. – CoolMind Oct 21 '22 at 07:17

How to list files in an android directory?

14 Answers14

Updated working method

MainActivity.java

Linked