Question

主要问题是我无法返回两个值帮助。我已经尝试了很多时间但没有成功。而且我是新手，所以请提前感谢我的代码。

这是我的代码

    public class calculate extends AsyncTask<String, String, String> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

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

            try {
                uss = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22INRUSD%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");
                JSONObject usjObj;
                usjObj = new JSONObject(uss);
                usResult = usjObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate");


                eurr = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22INREUR%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");
                JSONObject eurjObj;
                eurjObj = new JSONObject(eurr);
                eurResult = eurjObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate");
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (ClientProtocolException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return eurResult + usResult;
            ////PROBLEM IS HERE ACTUALLY I DON'T KNOW HOW TO RETURN TWO OR MORE VALUE/////"
        }

        @Override
        protected void onPostExecute(String usResult) {
            valueus = Double.parseDouble(usResult);
            inputus = lengthvalue * valueus;
            us.setText("" + inputus);

            valueeur = Double.parseDouble(eurResult);
            inputeur = lengthvalue * valueeur;
            eur.setText("" + inputeur);
        }

    }


    public String getJson(String url) throws ClientProtocolException, IOException {

        StringBuilder build = new StringBuilder();
        HttpClient client = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(url);
        HttpResponse response = client.execute(httpGet);
        HttpEntity entity = response.getEntity();
        InputStream content = entity.getContent();
        BufferedReader reader = new BufferedReader(new InputStreamReader(content));
        String con;
        while ((con = reader.readLine()) != null) {
            build.append(con);
        }
        return build.toString();
    }
}

Answer 1

你不应该试图把所有东西塞进String。有更好的数据结构来保存多个值：array，Vector，List等。将AsyntTask声明为：

public class calculate extends AsyncTask<String, String, String[]>

然后你的doInBackgorund方法会是这样的：

@Override
protected String doInBackground(String... params) {
    String[] result = new String[numResults];

    ...
    result[0] = usjObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate");

    ...
    result[1] = usjObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate");

    ...

    return result;
}

最后你的onPostExecute将是

@Override
protected void onPostExecute(String[] usResult) {
    ...
}

如何使用asyncTask解析来自多个URL的数据

1 个答案: