@Override
protected void onSaveInstanceState(@NonNull Bundle outState) {
super.onSaveInstanceState(outState);
final View advancedPad = findViewById(R.id.pad_advanced);
final View hexPad = findViewById(R.id.pad_hex);
final View matrixPad = findViewById(R.id.pad_matrix);
Panel panel = null;
if (advancedPad.getVisibility() == View.VISIBLE) {
panel = Panel.Advanced;
} else if (hexPad.getVisibility() == View.VISIBLE) {
panel = Panel.Hex;
} else if (matrixPad.getVisibility() == View.VISIBLE) {
panel = Panel.Matrix;
}
outState.putSerializable(KEY_PANEL, panel);
}
