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这是我从谷歌表下载信息到我的应用程序的代码。我的 android 工作室似乎找不到这个类。我能做些什么来解决这个问题？我迷路了。谢谢。我从本教程中获取了这段代码： http ://www.telerik.com/blogs/google-spreadsheet-as-data-source-android

package yrapps.szone;
import android.os.AsyncTask;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class DownloadWebpageTask extends AsyncTask<String, Void, String> {
    AsyncResult callback;

    public DownloadWebpageTask(AsyncResult  callback) {
        this.callback = callback;
    }

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

        // params comes from the execute() call: params[0] is the url.
        try {
            return downloadUrl(urls[0]);
        } catch (IOException e) {
            return "Unable to download the requested page.";
        }
    }

    // onPostExecute displays the results of the AsyncTask.
    @Override
    protected void onPostExecute(String result) {
        // remove the unnecessary parts from the response and construct a JSON
        int start = result.indexOf("{", result.indexOf("{") + 1);
        int end = result.lastIndexOf("}");
        String jsonResponse = result.substring(start, end);
        try {
            JSONObject table = new JSONObject(jsonResponse);
            callback.onResult(table);
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

    private String downloadUrl(String urlString) throws IOException {
        InputStream is = null;

        try {
            URL url = new URL(urlString);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setReadTimeout(10000 /* milliseconds */);
            conn.setConnectTimeout(15000 /* milliseconds */);
            conn.setRequestMethod("GET");
            conn.setDoInput(true);
            // Starts the query
            conn.connect();
            int responseCode = conn.getResponseCode();
            is = conn.getInputStream();

            String contentAsString = convertStreamToString(is);
            return contentAsString;
        } finally {
            if (is != null) {
                is.close();
            }
        }
    }

    private String convertStreamToString(InputStream is) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
}

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1 回答 1

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您无法解析符号，因为您没有在导入中包含 AsyncResult 类。AsyncResult 不是标准的 Android 代码。如果您访问链接中提到的 GitHub 存储库，我发现它是一个自定义类，与 DownloadWebpageTask 属于同一包的一部分。这就是他免费获得它的原因。但是您需要自己创建 AsyncResult。

这是他的来源：https ://github.com/telerik/Android-samples/blob/master/Blogs/Json-Reader/app/src/main/java/com/example/progress/json_reader/AsyncResult.java

于 2016-04-30T01:54:04.210 回答