final RelativeLayout layout = (RelativeLayout) findViewById(R.id.ataque);

mas.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        EditText extra = new EditText(getApplicationContext());
        int ntext = mispreferencias.getInt("contadortext", 0);
        RelativeLayout.LayoutParams p = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
        extra.setId(ntext);
        final int id_ = extra.getId();
        extra.setLayoutParams(p);
        editor.putInt("extra" + ntext, id_);
        editor.putInt("contadortext", ntext + 1);
        editor.commit();
        layout.addView(extra);
   }
});

int ntext = mispreferencias.getInt("contadortext", 0);

for (int i = 0; i < ntext; i++) {
    int ide = mispreferencias.getInt("extra" + i, 0);
    EditText edi = (EditText) findViewById(ide);
    editor.putString("text" + i, edi.getText().toString());
}

java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference