MainActivity.DownloadWebpageTask 不是抽象的，不会覆盖 AsyncTask 中的抽象方法 doInBackground(String...)

Question

public class MainActivity extends Activity {

    TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tv = (TextView) findViewById(R.id.data);

        String serviceUrl = "-"; // I can not show it
        String serviceKey = "-"; // I can not show it
        serviceKey = URLEncoder.encode(serviceKey);
        String strSrch = "406";
        String strUrl = serviceUrl + "?ServiceKey=" + serviceKey + "&strSrch=" + strSrch;

        new DownloadWebpageTask().execute(strUrl);
    }

    private class DownloadWebpageTask extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackgroud(String... urls) {
            try {
                return (String)downloadUrl((String)urls[0]);
            } catch (IOException e) {
                return "Download Fail";
            }
        }

        protected void onPostExecute(String result) {
            tv.append(result + "\n");
            tv.append("=======parsing result=========\n");

            try {
                XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
                factory.setNamespaceAware(true);
                XmlPullParser xpp = factory.newPullParser();

                xpp.setInput(new StringReader(result));
                int eventType = xpp.getEventType();
                boolean bSet = false;
                while (eventType != XmlPullParser.END_DOCUMENT) {
                    if (eventType == XmlPullParser.START_DOCUMENT) {
                        ;
                    } else if (eventType == XmlPullParser.START_TAG) {
                        String tag_name = xpp.getName();
                        if (tag_name.equals("busRouteNm") || tag_name.equals("busRouteId"))
                            bSet = true;
                    } else if (eventType == XmlPullParser.TEXT) {
                        if (bSet) {
                            String content = xpp.getText();
                            tv.append(content + "\n");
                            bSet = false;
                        }
                    } else if (eventType == XmlPullParser.END_TAG) {
                        ;
                    }
                    eventType = xpp.next();
                }
            } catch (Exception e) {
                tv.setText(e.getMessage());
            }
        }

        private String downloadUrl(String myurl) throws IOException {

            HttpURLConnection conn = null;
            try {
                URL url = new URL(myurl);
                conn = (HttpURLConnection) url.openConnection();
                BufferedInputStream buf = new BufferedInputStream(conn.getInputStream());
                BufferedReader bufreader = new BufferedReader(new InputStreamReader(buf, "utf-8"));
                String line = null;
                String page = "";
                while ((line = bufreader.readLine()) != null) {
                    page += line;
                }
                return page;
            } finally {
                conn.disconnect();
            }
        }
    }

}

"private class DownloadWebpageTask extends AsyncTask " 此行有错误：

Error:(44, 13) error: MainActivity.DownloadWebpageTask is not abstract and does not override abstract method doInBackground(String...) in AsyncTask

Answer 1

方法名称中有错别字。变化

protected String doInBackgroud

至

protected String doInBackground

Answer 2

更改此行：

private class DownloadWebpageTask extends AsyncTask<String, Void, String> {

至

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

MainActivity.DownloadWebpageTask 不是抽象的，不会覆盖 AsyncTask 中的抽象方法 doInBackground(String...)

MainActivity.DownloadWebpageTask is not abstract and does not override abstract method doInBackground(String...) in AsyncTask

java

android

android-asynctask