Question

JAVA文件

private void getWeatherData(String cityName) throws JSONException {
    HttpURLConnection conn = null;
    StringBuilder jsonResults = new StringBuilder();

    try {
        StringBuilder sb = new StringBuilder(WEATHER_API_BASE + API_KEY + TYPE + cityName +OUT_JSON);


        Log.e(TAG , sb.toString());

        URL url = new URL(sb.toString());
        conn = (HttpURLConnection) url.openConnection();
        InputStreamReader in = new InputStreamReader(conn.getInputStream());

        // Load the results into a StringBuilder
        int read;
        char[] buff = new char[1024];
        while ((read = in.read(buff)) != -1) {
            jsonResults.append(buff, 0, read);
        }
    } catch (MalformedURLException e) {
        Log.e(TAG, "Error processing Weather API URL", e);

    } catch (IOException e) {
        Log.e(TAG, "Error connecting to Weather API", e);
    } finally {
        if (conn != null) {
            conn.disconnect();
        }
    }

    try {
         Log.e(TAG, "in try2");

        // Create a JSON object hierarchy from the results
        JSONObject jsonObj = new JSONObject(jsonResults.toString());
        JSONArray forecastJsonArray = jsonObj.getJSONArray("hourly_forecast");
        Log.e(TAG , "Length:" + String.valueOf( forecastJsonArray.length() ));


    } catch (Exception e) {
        Log.e(TAG, "Cannot process JSON results", e);
    }

}

上面的代码适用于其他api，我从中检索JSON，但无法弄清楚为什么它不能用于此。

JSON http://api.wunderground.com/api/73d7d46dcd6153a7/hourly/q/Chandigarh.json

Answer 1

你如何消费api？你在使用AsyncTask吗？你不能简单地通过调用方法来进行api调用。网络操作需要异步运行。我试过在AsyncTask中运行你的代码，它确实有效。

private class WeatherDataTask extends AsyncTask<String, String, String> {

    public WeatherDataTask() {

    }

    @Override
    protected String doInBackground(String... params) {
        HttpURLConnection conn = null;
        StringBuilder jsonResults = new StringBuilder();

        try {
            StringBuilder sb = new StringBuilder(params[0]);
            URL url = new URL(sb.toString());
            conn = (HttpURLConnection) url.openConnection();
            InputStreamReader in = new InputStreamReader(conn.getInputStream());

            // Load the results into a StringBuilder
            int read;
            char[] buff = new char[1024];
            while ((read = in.read(buff)) != -1) {
                jsonResults.append(buff, 0, read);
            }
        } catch (MalformedURLException e) {
            Log.e("WeatherTask", "Error processing Weather API URL", e);

        } catch (IOException e) {
            Log.e("WeatherTask", "Error connecting to Weather API", e);
        } finally {
            if (conn != null) {
                conn.disconnect();
            }
        }

        return jsonResults.toString();
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);

        if(null != s){
            try {
                JSONObject jsonObj = new JSONObject(s);
                JSONArray forecastJsonArray = jsonObj.getJSONArray("hourly_forecast");

                Log.i("ForeCastJason", forecastJsonArray.toString());
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }
}

调用此方法类

new WeatherDataTask().execute("http://api.wunderground.com/api/73d7d46dcd6153a7/hourly/q/Chandigarh.json");

Answer 2

我使用Async Http Client

解决了这个问题

我无法从应用程序中的json检索数据

2 个答案: