Can't delete files from internal storage folder

Question

I want to delete all files from Download folder

I am trying this approach -

File mydir = new File(String.valueOf(Environment.getExternalStoragePublicDirectory("Download")));
File lister = mydir.getAbsoluteFile();

System.out.println("Total files: " + lister.list().length);

for (String list : lister.list()) {
    File f = new File(lister, list);
    if (f.delete())
        System.out.println(list + " is Deleted!");
    else
        System.out.println(list + " not deleted!");
}

It doesn't work, f.delete is returning false.

I have already looked at many such questions on SO, most of them suggest the use of delete() or getCanonicalFile().delete(). This is just not working.

manifest-

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

Answer 1

Fixed it.

My app was requesting the user for READ permission only, not WRITE.

Deleting any file requires WRITE permission. So i changed READ to WRITE, it worked!

 if (ContextCompat.checkSelfPermission(MainActivity.this
            , Manifest.permission.**WRITE**_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) 
     {   
       // ...
     }