我无法从AsyncTask子类中的doInBackground方法获取数据

Question

我正在尝试在我的应用程序中获取地震数据，结果我的应用停止工作。我的代码中没有错误。甚至我也添加了互联网权限。但当获取数据时，我认为会发生这种错误。我已调试过，但找不到问题。

日志猫：

2021-03-27 15:23:32.118 9533-9560/com . example . quakereportapp E/eglCodecCommon:glUtilsParamSize:unknow param 0x 000082 da 2021-03-27 15:23:32.118 9533-9560/com . example . quakereportapp E/eglCodecCommon:glUtilsParamSize:unknow param 0x 000082 da ioctl _ ping

我的AsyncTask子类

private void updateUi(List<Earthquake> earthquakes) {
    listView = findViewById(R.id.list_view);
    ArrayList<Earthquake> earthquake = QueryUtils.fetchEarthquakeData(url);
    EarthquakeAdapter earthquakeAdapterArrayAdapter = new EarthquakeAdapter(this, earthquake);
    listView.setAdapter(earthquakeAdapterArrayAdapter);
}
private class EarthQuakeAsyncTask extends AsyncTask<String, Void, List<Earthquake>> {
 
    @Override
    protected  ArrayList<Earthquake> doInBackground(String... urls) {
        ArrayList<Earthquake> result = QueryUtils.fetchEarthquakeData(urls[0]);
        return result;
    }


    @Override
    protected void onPostExecute(List<Earthquake> result) {
        updateUi(result);
    }

我的来自QueryUtils Class的JSON Extractor方法

private static ArrayList<Earthquake> extractFeatureFromJson(String earthquakeJSON) {
    // If the JSON string is empty or null, then return early.
    if (TextUtils.isEmpty(earthquakeJSON)) {
        return null;
    }

    ArrayList<Earthquake> earthquakes = new ArrayList<>();


    try {
        JSONObject baseJsonResponse = new JSONObject(earthquakeJSON);
        JSONArray earthquakeArray = baseJsonResponse.getJSONArray("features");

        for (int i = 0; i < earthquakeArray.length(); i++) {
            //creates object from the given array
            JSONObject currentEarthquake = earthquakeArray.getJSONObject(i);
            //stores all the data from properties to properties object
            JSONObject properties = currentEarthquake.getJSONObject("properties");
            //here we assign the value of the specified keys from the properties
            String magnitude = properties.getString("mag");
            String location = properties.getString("place");
            long time = properties.getLong("time");
            //and now we create a new earthquake in every loop
            Earthquake earthquake = new Earthquake(magnitude, location, time);
            //finally we add it to the earthquakes list
            earthquakes.add(earthquake);
        }
    } catch (JSONException e) {
        Log.e(LOG_TAG, "Problem parsing the earthquake JSON results", e);
    }
    return earthquakes;
}

Answer 1

引发异常是因为您是从主线程调用 API。代码中的问题是您调用 API 两次。一次在 do InBackground 中，然后再次在更新Ui 中。从更新中删除对查询工具的调用地球地震数据（网址），它应该看起来像这样。

private void updateUi(List<Earthquake> earthquakes) {
    listView = findViewById(R.id.list_view);
    EarthquakeAdapter earthquakeAdapterArrayAdapter = new EarthquakeAdapter(this, earthquakes);
    listView.setAdapter(earthquakeAdapterArrayAdapter);
}