How can I delete an external folder with Android?

I have been searching for it but theres no any answer to my problem. I am programming an app and I want to delete an external folder. For example /storage/emulated/0/MyFolder, there is a lot of ways to create and read files from a internal app folder and an external app folder, but I dont know how to acces to files in "/storage/emulated/0/...".

Thanks.

  public static void deleteDir(Context ctx) {

        try {
            File myFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath()
                                + File.separator
                                + "MyFolder");
            }
            if (myFile.exists()) {
                deleteRecursive(myFile);
            }
        }catch (Exception ignored){
            Log.e("Delete error File: %s",ignored.getMessage());
        }
    }

    private static void deleteRecursive(File myFile) {
        if (myFile.isDirectory())
            for (File child : myFile.listFiles())
                deleteRecursive(child);
        Log.e("MyFolder Files Deleted!!! : %s", myFile.delete());
    }

• Add this lines to app manifest.xml

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

Update - As mentioned by CommonsWare runtime permission request needed for Android 6+

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN
            && ActivityCompat.checkSelfPermission(context, Manifest.permission.WRITE_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(context, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 101);
    } else {
        deleteDir(context);
    }

Your Activity

  @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 101:
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    deleteDir(context);
                }
        }
    }