参考 http://www.it165.net/pro/html/201404/12375.html
@Optional @InjectView
@Optional @onClick
1.@Optional @InjectView(R.id.might_not_be_there) TextView mightNotBeThere;
2. 3.@Optional @OnClick(R.id.maybe_missing) void onMaybeMissingClicked() {4.// TODO ...5.}
无需强转
TextView firstName = ButterKnife.findById(view, R.id.first_name);
原文：http://www.cnblogs.com/wjw334/p/4375650.html