<Spinner
        android:id="@+id/spinner1"
        android:layout_width="319dp"
        android:layout_height="52dp"
        android:layout_marginTop="11dp"
        android:entries="@array/state_arrays"/>

if (Spinner1.getSelectedItem().toString().trim().equals("select a city")) {
    Toast.makeText(CallWs.this, "Error", Toast.LENGTH_SHORT).show();
}

public static boolean validateSpinner(AppCompatSpinner[] fields) {
        for (int i = 0; i < fields.length; i++) {
            AppCompatSpinner currentField = fields[i];
            if (currentField.getCount() <= 0 || currentField.getSelectedItem().toString().contains("Your Default Value")) {
                ((TextView) currentField.getSelectedView()).setError(fieldRequired);
                return false;
            }
        }
        return true;
    }

if (!validateSpinner(new AppCompatSpinner[]{citySpinner}))
             Utils.showSnackbar(mainLayout, selectCityTxt);