android - java.net.UnknownHostException 无法使用 RxJava 转换为 retrofit2.adapter.rxjava.HttpException

Question

我在日志中收到此错误:

Caused by java.lang.ClassCastException: java.net.UnknownHostException cannot be cast to retrofit2.adapter.rxjava.HttpException

这就是我的 onError 方法。该错误可能是在设备未连接时导致的。

  @Override
        public void onError(Throwable e) {
            assert e != null;
            Timber.d(e);
            HttpException exception = (HttpException) e;
            assert view != null;
            view.hideRefreshSpinner();
            if (exception.code() == HttpURLConnection.HTTP_BAD_REQUEST) {
                view.showSnackbarInvalidError();
            } else {
                view.showUnauthorizedError();
            }

        }

Answer 1

发生这种情况是因为您收到的是 java.net.UnknownHostException 而不是 retrofit2.adapter.rxjava.HttpException 的实例。如果您查看 doc ，它说:

• Direct body (e.g., Observable) calls onNext with the deserialized body for 2XX responses and calls onError with HttpException for non-2XX responses and IOException for network errors.
• Response wrapped body (e.g., Observable>) calls onNext with a Response object for all HTTP responses and calls onError with IOException for network errors
• Result wrapped body (e.g., Observable>) calls onNext with a Result object for all HTTP responses and errors.

所以你收到了一个网络错误。

另见 this

您可以像这样包装您的代码:

@Override
public void onError(Throwable e) {
    assert e != null;
    Timber.d(e);
    if (e instanceof HttpException) {
        assert view != null;
        view.hideRefreshSpinner();
        if (((HttpException) e).code() == HttpURLConnection.HTTP_BAD_REQUEST) {
            view.showSnackbarInvalidError();
        } else {
            view.showUnauthorizedError();
        }
    }
}