HTTP Get请求-不兼容的类型

Question

public void refreshWeather（最终字符串位置）{

    new AsyncTask<String, Void, String>()

    {
        @Override
        protected String doInBackground(String... strings) {

            String YQL = String.format("select * from weather.forecast where woeid in (select woeid from geo.places(1) where text=\"%s\")",location);
            String endpoint = String.format("https://query.yahooapis.com/v1/public/yql?q=%s&format=json", Uri.encode(YQL));

            try {
                URL url = new URL(endpoint);
                URLConnection connection = url.openConnection();
                InputStream inputStream = connection.getInputStream();
                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                StringBuilder result = new StringBuilder();
                boolean line;

                while ((line = reader.readLine()!= null)){
                    result.append(line);
                }

                return result.toString();

            } catch (Exception e) {
                error = e;
                }
            return null;
        }

        /**

         onPostExecute checks first if there is a service failure, then if city is valid, then it
         populates the data from the city and goes to method serviceSuccess and populates the fields with the retrieved data

         */

        @Override
        protected void onPostExecute(String s) {

            if (s == null && error != null){
                callback.serviceFailure(error);
                return;
            }

            try {
                JSONObject data = new JSONObject(s);
                JSONObject queryResults = data.optJSONObject("query");

                int count = queryResults.optInt("count");
                if (count == 0){

                    callback.serviceFailure(new LocationWeatherException("No Weather Info Found for" + location));
                    return;
                }


                Channel channel = new Channel();
                channel.populate(queryResults.optJSONObject("results").optJSONObject("channel"));

                callback.serviceSuccess(channel);

                } catch (JSONException e) {

                callback.serviceFailure(e);
            }
        }
    }.execute(location);
}

Answer 1

在java中进行比较时，使用==进行检查。进行比较时也不要设置变量，例如:line=reader.readline()！=null

这将导致一个错误，因为当您试图设置变量名时，您检查它等于什么。

在调用变量之前尝试设置该变量，然后使用line！=nullex:

line = reader.readLine();
if(line != null) {
    //do something
}