如何取消改造请求

Question

我滚动浏览Retrofit 的官方文档,并决定在我的项目中实现类似的东西,这样用户总是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?");
                }
            }

但是红色的下划线是失败的方法.我不明白是什么问题,因为这个方法我们最初提出类Call(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

error.isCanceled()据我所记,在改造中似乎并不存在.如果您希望能够取消请求,您可以切换到他们有call.cancel()方法的Retrofit 2,或者在当前版本的Retrofit中,您可以Callback扩展类以创建您自己的类,CancellableCallback如下所示:

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);
        }
    }
}

编辑

然后你可以像这样使用它:

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);

然后像这样取消它:

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

Answer 2

你可以取消请求,如:

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

并得到取消的回调像:

@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?");
       }
}

您可以在这里查看更多信息.