java - 设置 postDelayed Runnable 时 BufferedInputStream 关​​闭

Question

我的 GameActivity 是一个简单的测验。我设置了两个 Runnable:mRunnableQuestion 和 mRunnableQuestionWithPenalty。逻辑是:mRunnableQuestion显示新问题并等待30秒，当用户在这段时间内没有回答时，另一个Runnable被调用，这会给用户积分惩罚:

private Runnable mRunnableQuestion = new Runnable() {
    @Override
    public void run() {
        new AsyncAPIGetQuestion().execute(mCategoryId);
        mHandler.postDelayed(mRunnableQuestionWithPenalty, 30000);
    }
};

当然，当用户及时回答时，我会给用户积分并重新启动 Runnable:

mHandler.removeCallbacksAndMessages(null);
mHandler.post(mRunnableQuestion);

效果非常好。然而，我想根据正确/错误答案给卡片上色，然后等待 5 秒钟。所以我将上面的代码更改为:

mHandler.removeCallbacksAndMessages(null);
colorAnswers();
mHandler.postDelayed(mRunnableQuestion, 5000);

这就是问题开始的地方。当我运行我的应用程序时，在回答 2、3 或 4 个问题后，我收到 EOF/BufferedInputStream 错误:

    03-04 13:38:24.107 16506-16532/com.my.pkg W/System.err: java.io.EOFException
    03-04 13:38:24.107 16506-16532/com.my.pkg W/System.err:     at com.android.okio.RealBufferedSource.readUtf8LineStrict(RealBufferedSource.java:95)
    03-04 13:38:24.107 16506-16532/com.my.pkg W/System.err:     at com.
    android.okhttp.internal.http.HttpConnection.readResponse(HttpConnection.java:175)
    03-04 13:38:24.107 16506-16532/com.my.pkg W/System.err:     at com.android.okhttp.internal.http.HttpTransport.readResponseHeaders(HttpTransport.java:101)
    03-04 13:38:24.107 16506-16532/com.my.pkg W/System.err:     at com.android.okhttp.internal.http.HttpEngine.readResponse(HttpEngine.java:616)
    03-04 13:38:24.107 16506-16532/com.my.pkg W/System.err:     at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:379)
    03-04 13:38:24.107 16506-16532/com.my.pkg W/System.err:     at com.android.okhttp.internal.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:323)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at com.android.okhttp.internal.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:190)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at com.my.pkg.JSONParser.getJSONFromUrl(JSONParser.java:45)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at com.my.pkg.GameActivity$AsyncAPIGetQuestion.doInBackground(GameActivity.java:317)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at com.my.pkg.GameActivity$AsyncAPIGetQuestion.doInBackground(GameActivity.java:299)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at android.os.AsyncTask$2.call(AsyncTask.java:288)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
    03-04 13:38:24.108 16506-16532/com.my.pkg W/System.err:     at java.lang.Thread.run(Thread.java:818)
    03-04 13:38:24.108 16506-16532/com.my.pkg E/JSONParser.java: Error converting result java.io.IOException: BufferedInputStream is closed

只有当我在那里添加额外的 postDelayed() 时才会发生这种情况。之前没问题。

我的 AsyncTask 的 doInBackground 部分由 Runnable 执行，并返回如上所述的错误

    @Override
    protected JSONArray doInBackground(String... params) {
        JSONParser jParser = new JSONParser();
        JSONArray json = jParser.getJSONFromUrl(apiURL);
        return json;
    }

还有 JSONParser.getJSONFromURL:

public JSONArray getJSONFromUrl(String urlSource) {
    try {
        URL url = new URL(urlSource);
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setDoOutput(true);
        urlConnection.setChunkedStreamingMode(0);
        inputStream = new BufferedInputStream(urlConnection.getInputStream());
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
            if(!reader.ready()) {
                break;
            }
        }
        inputStream.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e(TAG, "Error converting result " + e.toString());
    }

    try {
        jArr = new JSONArray(json);
    } catch (JSONException e) {
        Log.e(TAG, "Error parsing data " + e.toString());
    }

    return jArr;
}

我真的很感激任何帮助。祝一切顺利!

Answer 1

看来我解决了这个问题。

问题出在我的 jParser.getJSONFromUrl() 方法中，特别是这些行:

URL url = new URL(urlSource);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setDoOutput(true);

当您使用 POST/PUT 请求时，您似乎仅将 setDoOutput 参数设置为 true。如果您只想执行 GET 请求(例如我的情况)，您应该将其设置为 false:

urlConnection.setDoOutput(false);

否则，您最终可能会遇到如上所述的错误。

向社区致以最诚挚的问候!