SnackBarの文字色を自由に設定する方法 ref: http://qiita.com/wakwak3125/items/79e0097767be5b2ea798

ChangeSnackBarTextColorSample

public class MainActivity extends AppCompatActivity {

    @Bind(R.id.root)
    LinearLayout root;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
    }

    private void showSnackBar(String msg, int color) {
        Snackbar snackbar = Snackbar.make(root, msg, Snackbar.LENGTH_SHORT);
        TextView textView = (TextView) snackbar.getView().findViewById(android.support.design.R.id.snackbar_text);
        textView.setTextColor(color);
        snackbar.show();
    }

    @OnClick(R.id.red)
    public void showRedTextSnackBar() {
        showSnackBar("赤です", Color.RED);
    }

    @OnClick(R.id.blue)
    public void showBlueTextSnackBar() {
        showSnackBar("青です", Color.BLUE);
    }

    @OnClick(R.id.white)
    public void showWhiteTextSnackBar() {
        showSnackBar("白です", Color.WHITE);
    }
}