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 lt 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

User · Answer

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

User · Answer

I just discovered that   new File   sdcard    listFiles    returns null if you do not have    lt uses-permission android name  android permission READ EXTERNAL STORAGE    gt    set in your AndroidManifest xml file

User · Answer

In order to access the files  the permissions must be given in the manifest file    lt uses-permission android name  android permission READ EXTERNAL STORAGE    gt    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  lt  files length  i          Log d  Files    FileName     files i  getName

User · Answer

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 lt File gt  files    List lt File gt   FileUtils listFiles dir  TrueFileFilter INSTANCE  TrueFileFilter INSTANCE       for  File file   files            System out println  file      file getCanonicalPath

User · Answer

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   lt uses-permission android name  android permission READ EXTERNAL STORAGE    gt    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

User · Answer

String   listOfFiles   getActivity   getFilesDir   list      or  String   listOfFiles   Environment getExternalStoragePublicDirectory  Environment DIRECTORY DOWNLOADS  list

User · Answer

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  lt  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

User · Answer

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

User · Answer

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

User · Answer

Updated working method My minSdkversion is 21  so I m using ContextCompat checkSelfPermission   method to grant permissions apart from also adding the  lt uses-permission android name  quot android permission READ EXTERNAL STORAGE quot   gt  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  amp  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    quot  Download  quot           Log d  quot Files quot    quot Path   quot    path           File directory   new File path           File   files   directory listFiles            if directory canRead    amp  amp  files  null                Log d  quot Files quot    quot Size   quot    files length               for File file  files                  Log d  quot FILE quot  file getName                       else             Log d  quot Null  quot    quot it is null quot

User · Answer

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

[android] How to list files in an android directory?

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