Question

我滚动浏览Retrofit的官方documentation并决定在我的项目中实现类似的功能，以便用户始终可以选择取消下载文件，一切都能正常工作。实施适当的方法，如果未能规定以下内容：

service.upload1(file1, str, stringMap, new Callback<ImageUpload>() {
            @Override
            public void success(final ImageUpload imageUpload, Response response) {
                mRecyclerView.post(new Runnable() {
                    @Override
                    public void run() {
                        ...
                });
            }

            @Override
            public void failure(RetrofitError error) {
                if (error.isCanceled()) {
                    Log.e(TAG, "request is cancelled");
                } else {
                    Log.e(TAG, "other larger issue, i.e. no network connection?");
                }
            }

但是在失败方法中强调红色 isCanceled 。我不明白是什么问题，因为这个方法我们最初提出了类调用（也许是因为发誓我而不是类Call是RetrofitError？）请告诉我如何修复。我使用改装1.9，我不需要继续改造2.

Answer 1

据我记得，

error.isCanceled()似乎并没有出现在Retrofit中。如果您希望能够取消请求，您可以切换到具有call.cancel()方法的Retrofit 2，或者在当前版本的Retrofit中，您可以扩展Callback类以创建您自己的类CancellableCallback这样：

public class CancellableCallback<T> implements Callback<T> {

    private Callback<T> callback;

    private boolean canceled;

    private CancellableCallback() {}

    public CancellableCallback(Callback<T> callback) {
        this.callback = callback;
        canceled = false;
    }

    public void cancel() {
        canceled = true;
        callback = null;
    }

    @Override
    public void success(T o, Response response) {
        if (!canceled) {
            callback.success(o, response);
        }
    }

    @Override
    public void failure(RetrofitError error) {
        if (!canceled) {
            callback.failure(error);
        }
    }
}

修改

然后您可以像这样使用它：

CancellableCallback callback = new Callback<ImageUpload>() { @Override public void success(final ImageUpload imageUpload, Response response) { mRecyclerView.post(new Runnable() { @Override public void run() { ... }); } @Override public void failure(RetrofitError error) { } }; service.upload1(file1, str, stringMap, callback);

然后取消它：

if (some condition && callback != null) { callback.cancel(); }

Answer 2

您可以取消请求，如：

// something happened, for example: user clicked cancel button
service.cancel();

并获得取消回调，如：

@Override
public void onFailure(Call<ResponseBody> call, Throwable t) {
       if (call.isCanceled()) {
           Log.e(TAG, "request was cancelled");
       }
       else {
           Log.e(TAG, "other larger issue, i.e. no network connection?");
       }
}

您可以查看here了解更多信息。

Answer 3

您应该使用Retrofit 2并更改接口方法签名以返回Call对象。要执行请求，请调用enqueue方法。之后，您可以调用cancel方法取消请求。

Answer 4

你应该切换到retrofit2，然后写这样的东西 -

service.upload1(file1, str, stringMap, new Callback<ImageUpload>() {
        @Override
        public void onResponse(Call<ImageUpload> call, Response<Topics> response) {

            //retrieve your resbonse body here like this -
            //   ImageUpload imageUpload = response.body();
            mRecyclerView.post(new Runnable() {
                @Override
                public void run() {
                    ...
            });
        }

        @Override
        public void onFailure(Call<ImageUpload> call, Throwable t) {
            if (call.isCanceled()) {
                Log.e(TAG, "request is cancelled");
            } else {
                Log.e(TAG, "other larger issue, i.e. no network connection?");
            }
        }

如何取消改造请求

4 个答案: