使用loopj Android异步Http客户端进行同步调用

Question

我试图在loopj上使用setUseSynchronousMode来等待http调用的结果，然后在一种情况下继续。我试着:

    AsyncHttpResponseHandler responseHandler = new AsyncHttpResponseHandler() {
        @Override
        public void onSuccess(int statusCode, Header[] headers, byte[] response) {
            Log.d("TEST", "Got results");
        }
    };
    AsyncHttpClient client = new AsyncHttpClient();
    responseHandler.setUseSynchronousMode(true);
    client.get("http://www.google.com", responseHandler);
    Log.d("TEST", "Don't want to get here until after getting results");

但是结果是:

07-11 19:48:05.631 D/TEST﹕ Don't want to get here until after getting results
07-11 19:48:05.814 D/TEST﹕ Got results

我是否误解了setUseSynchronousMode应该做什么?

Answer 1

您应该使用SyncHttpClient而不是AsyncHttpClient。setUseSynchronousMode对AsyncHttpClient没有预期的效果

Answer 2

为了使AsyncHttpClient的同步版本具有取消它的能力，我在主线程上做所有事情。以前我在AsyncTask中运行它，一旦AsyncHttpClient.post()被调用，AsyncTask就会完成，我无法跟踪AsyncHttpClient实例。

SyncHttpClient不允许我取消上传，所以我知道我必须使用AsyncHttpClient并进行适当的更改。

下面是我上传一个使用AsyncHttpClient并允许取消的文件的类:

public class AsyncUploader {
    private String mTitle;
    private String mPath;
    private Callback mCallback;
    public void AsyncUploader(String title, String filePath, MyCallback callback) {
        mTitle = title;
        mPath = filePath;
        mCallback = callback;
    }
    public void startTransfer() {
        mClient = new AsyncHttpClient();
        RequestParams params = new RequestParams();
        File file = new File(mPath);
        try {
            params.put("title", mTitle);
            params.put("video", file);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        mClient.setTimeout(50000);
        mClient.post(mContext, mUrl, params, new ResponseHandlerInterface() {
            @Override
            public void sendResponseMessage(HttpResponse response) throws IOException {
                HttpEntity entity = response.getEntity();
                if (entity != null) {
                    InputStream instream = entity.getContent();
                    // TODO convert instream to JSONObject and do whatever you need to
                    mCallback.uploadComplete();
                }
            }
            @Override
            public void sendProgressMessage(int bytesWritten, int bytesTotal) {
                mCallback.progressUpdate(bytesWritten, bytesTotal);
            }
            @Override
            public void sendFailureMessage(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {
                mCallback.failedWithError(error.getMessage());
            }
        });
    }
    /**
    * Cancel upload by calling this method
    */
    public void cancel() {
        mClient.cancelAllRequests(true);
    }
}

你可以这样运行它:

AsyncUploader uploader = new AsyncUploader(myTitle, myFilePath, myCallback);
uploader.startTransfer();
/* Transfer started */
/* Upon completion, myCallback.uploadComplete() will be called */

取消上传，只需调用cancel():

uploader.cancel();