//If User was asked permission before and denied
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);

alertDialogBuilder.setTitle("Permission needed");
alertDialogBuilder.setMessage("Storage permission needed for accessing photos");
alertDialogBuilder.setPositiveButton("Open Setting", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialogInterface, int i) {
        Intent intent = new Intent();
        intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
        Uri uri = Uri.fromParts("package", MainActivity.this.getPackageName(),
                null);
        intent.setData(uri);
        MainActivity.this.startActivity(intent);
    }
});
alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialogInterface, int i) {
        Log.d(TAG, "onClick: Cancelling");
    }
});

AlertDialog dialog = alertDialogBuilder.create();
dialog.show();